Why nothing since 1.8.0?

Why nothing since 1.8.0?

[Stephen Hemminger]

Ok, so 1.8.0 came out almost a month ago and none of the patches
that were deferred waiting for the release got merged since then.
Last commit in git is the 1.8.0 release.

Where is the post-merge window bundle, where are the later commits?
Lots of patches are sitting rotting in patchwork...

Re: Why nothing since 1.8.0?

[Neil Horman]

On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger wrote:
> Ok, so 1.8.0 came out almost a month ago and none of the patches
> that were deferred waiting for the release got merged since then.
> Last commit in git is the 1.8.0 release.
> 
> Where is the post-merge window bundle, where are the later commits?
> Lots of patches are sitting rotting in patchwork...
> 
> 

+1, I've had the same questions.
Neil

Re: Why nothing since 1.8.0?

[Zhang, Helin]

+1, Some patch set might be ready for being merged.

> -----Original Message-----
> From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> Sent: Thursday, January 15, 2015 5:02 AM
> To: Stephen Hemminger
> Cc: dev-VfR2kkLFssw@public.gmane.org
> Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> 
> On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger wrote:
> > Ok, so 1.8.0 came out almost a month ago and none of the patches that
> > were deferred waiting for the release got merged since then.
> > Last commit in git is the 1.8.0 release.
> >
> > Where is the post-merge window bundle, where are the later commits?
> > Lots of patches are sitting rotting in patchwork...
> >
> >
> 
> +1, I've had the same questions.
> Neil

Re: Why nothing since 1.8.0?

[Ouyang, Changchun]

> -----Original Message-----
> From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang, Helin
> Sent: Thursday, January 15, 2015 12:15 PM
> To: Neil Horman; Stephen Hemminger
> Cc: dev-VfR2kkLFssw@public.gmane.org
> Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> 
> +1, Some patch set might be ready for being merged.
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> > Sent: Thursday, January 15, 2015 5:02 AM
> > To: Stephen Hemminger
> > Cc: dev-VfR2kkLFssw@public.gmane.org
> > Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> >
> > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger wrote:
> > > Ok, so 1.8.0 came out almost a month ago and none of the patches
> > > that were deferred waiting for the release got merged since then.
> > > Last commit in git is the 1.8.0 release.
> > >
> > > Where is the post-merge window bundle, where are the later commits?
> > > Lots of patches are sitting rotting in patchwork...
> > >
> > >
> >
> > +1, I've had the same questions.
> > Neil

+1,  the earlier some patches are merged into mainline, and the easier those sequent patch sets can resolve their conflicts.
Thanks
Changchun

Re: Why nothing since 1.8.0?

[Thomas Monjalon]

2015-01-15 04:27, Ouyang, Changchun:
> From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang, Helin
> > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> > > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger wrote:
> > > > Ok, so 1.8.0 came out almost a month ago and none of the patches
> > > > that were deferred waiting for the release got merged since then.
> > > > Last commit in git is the 1.8.0 release.
> > > >
> > > > Where is the post-merge window bundle, where are the later commits?
> > > > Lots of patches are sitting rotting in patchwork...
> > >
> > > +1, I've had the same questions.
> > > Neil
> > 
> > +1, Some patch set might be ready for being merged.
> 
> +1,  the earlier some patches are merged into mainline, and the easier those
> sequent patch sets can resolve their conflicts.

+1, there are some patches which are properly reviewed

Reminder: sub-tree to manage specific part of DPDK can be open on request

-- 
Thomas, back on track

Re: Why nothing since 1.8.0?

[Neil Horman]

On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon wrote:
> 2015-01-15 04:27, Ouyang, Changchun:
> > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang, Helin
> > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> > > > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger wrote:
> > > > > Ok, so 1.8.0 came out almost a month ago and none of the patches
> > > > > that were deferred waiting for the release got merged since then.
> > > > > Last commit in git is the 1.8.0 release.
> > > > >
> > > > > Where is the post-merge window bundle, where are the later commits?
> > > > > Lots of patches are sitting rotting in patchwork...
> > > >
> > > > +1, I've had the same questions.
> > > > Neil
> > > 
> > > +1, Some patch set might be ready for being merged.
> > 
> > +1,  the earlier some patches are merged into mainline, and the easier those
> > sequent patch sets can resolve their conflicts.
> 
> +1, there are some patches which are properly reviewed
> 
> Reminder: sub-tree to manage specific part of DPDK can be open on request
> 
Ok, I think what you're saying here is you're too busy to handle all the patches
comming in at the moment.  As such I'd like to propose a sub-tree encompassing
all the pmds in DPDK.  I would envision that including all the acutal pmd's in
the tree, as well as the infrastructure that is used to interface them to the
core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
and send you pull requests.

If you could set me up with a login to dpdk.org, I'd appreciate it.

Thanks!
Neil

> -- 
> Thomas, back on track
> 

Re: Why nothing since 1.8.0?

[Thomas Monjalon]

2015-01-15 08:06, Neil Horman:
> On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon wrote:
> > 2015-01-15 04:27, Ouyang, Changchun:
> > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang, Helin
> > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> > > > > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger wrote:
> > > > > > Ok, so 1.8.0 came out almost a month ago and none of the patches
> > > > > > that were deferred waiting for the release got merged since then.
> > > > > > Last commit in git is the 1.8.0 release.
> > > > > >
> > > > > > Where is the post-merge window bundle, where are the later commits?
> > > > > > Lots of patches are sitting rotting in patchwork...
> > > > >
> > > > > +1, I've had the same questions.
> > > > > Neil
> > > > 
> > > > +1, Some patch set might be ready for being merged.
> > > 
> > > +1,  the earlier some patches are merged into mainline, and the easier those
> > > sequent patch sets can resolve their conflicts.
> > 
> > +1, there are some patches which are properly reviewed
> > 
> > Reminder: sub-tree to manage specific part of DPDK can be open on request
> 
> Ok, I think what you're saying here is you're too busy to handle all the patches
> comming in at the moment.  As such I'd like to propose a sub-tree encompassing
> all the pmds in DPDK.  I would envision that including all the acutal pmd's in
> the tree, as well as the infrastructure that is used to interface them to the
> core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
> and send you pull requests.

The list of PMDs is increasing:
	librte_pmd_af_packet
	librte_pmd_bond
	librte_pmd_e1000
	librte_pmd_enic
	librte_pmd_i40e
	librte_pmd_ixgbe
	librte_pmd_pcap
	librte_pmd_ring
	librte_pmd_virtio
	librte_pmd_vmxnet3
	librte_pmd_xenvirt
There is already some sub-trees for bnx2x, fm10k and i40e:
	http://dpdk.org/browse/

> If you could set me up with a login to dpdk.org, I'd appreciate it.

It is preferred to have 1 sub-tree per module.
What do you think of managing contributions for af_packet and/or virtio?
It would make sense as virtio is a RedHat technology.
Maybe it could include vhost lib and example.

Thanks for proposing
-- 
Thomas

Re: Why nothing since 1.8.0?

[Neil Horman]

On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> 2015-01-15 08:06, Neil Horman:
> > On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon wrote:
> > > 2015-01-15 04:27, Ouyang, Changchun:
> > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang, Helin
> > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> > > > > > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger wrote:
> > > > > > > Ok, so 1.8.0 came out almost a month ago and none of the patches
> > > > > > > that were deferred waiting for the release got merged since then.
> > > > > > > Last commit in git is the 1.8.0 release.
> > > > > > >
> > > > > > > Where is the post-merge window bundle, where are the later commits?
> > > > > > > Lots of patches are sitting rotting in patchwork...
> > > > > >
> > > > > > +1, I've had the same questions.
> > > > > > Neil
> > > > > 
> > > > > +1, Some patch set might be ready for being merged.
> > > > 
> > > > +1,  the earlier some patches are merged into mainline, and the easier those
> > > > sequent patch sets can resolve their conflicts.
> > > 
> > > +1, there are some patches which are properly reviewed
> > > 
> > > Reminder: sub-tree to manage specific part of DPDK can be open on request
> > 
> > Ok, I think what you're saying here is you're too busy to handle all the patches
> > comming in at the moment.  As such I'd like to propose a sub-tree encompassing
> > all the pmds in DPDK.  I would envision that including all the acutal pmd's in
> > the tree, as well as the infrastructure that is used to interface them to the
> > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
> > and send you pull requests.
> 
> The list of PMDs is increasing:
> 	librte_pmd_af_packet
> 	librte_pmd_bond
> 	librte_pmd_e1000
> 	librte_pmd_enic
> 	librte_pmd_i40e
> 	librte_pmd_ixgbe
> 	librte_pmd_pcap
> 	librte_pmd_ring
> 	librte_pmd_virtio
> 	librte_pmd_vmxnet3
> 	librte_pmd_xenvirt
> There is already some sub-trees for bnx2x, fm10k and i40e:
> 	http://dpdk.org/browse/
> 
Yes, and I've mentioned before that that is an absolutely silly way to break out
subtrees.  You have to find a balance of workload distribution and developer
convienience.

I also note that these are problematic because you're not merging anything
from them. Is it your intention to keep bnx2 and fm10k separate in perpituity?
If so, thats a real problem, because then we effectively just have several out
of tree drivers, and thats just unacceptible.

> > If you could set me up with a login to dpdk.org, I'd appreciate it.
> 
> It is preferred to have 1 sub-tree per module.
> What do you think of managing contributions for af_packet and/or virtio?
> It would make sense as virtio is a RedHat technology.
> Maybe it could include vhost lib and example.
> 
No, for reasons I've mentioned before.  If you take each pmd/library and create
a subtree for it, you've created the most fine grained control of subtrees you
could ask for, but you've created a nighmare of a burden on developers who want
to update any code, especially if they have patches that hit multiple trees.

Look at some of the stats in the dpdk tree:

Library		Commits between 1.7.0 and 1.8.0
librte_acl		5
librte_cfgfile		0
librte_cmdline		4
librte_compat		0
librte_distributor 	5
librte_eal 		125
librte_ether 		31
librte_hash 		1
librte_ip_frag 		5
librte_ivshmem 		0
librte_kni 		2
librte_kvargs 		0
librte_lpm 		1
librte_malloc 		1
librte_mbuf 		39
librte_mempool 		4
librte_meter 		0
librte_net 		4
librte_pipeline 	0
librte_pmd_af_packet 	4
librte_pmd_bond 	20
librte_pmd_e1000 	21
librte_pmd_enic 	12
librte_pmd_i40e 	90
librte_pmd_ixgbe 	83
librte_pmd_pcap 	4
librte_pmd_ring 	0
librte_pmd_virtio 	21
librte_pmd_vmxnet3 	21
librte_pmd_xenvirt 	6
librte_port 		6
librte_power 		3
librte_ring 		2
librte_sched 		1
librte_table 		7
librte_timer 		0
librte_vhost 		30

If you look at all of the pmds in the dpdk tree, we're talking about ~300
patches per release.  If you look at the net-next tree for the linux kernel,
Dave Miller merged 569 patches on his own (based on the following command:
git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/ net/core/ | wc
-l)

And that doesn't account for the ~500 patches that come in via pull request from
the wireless subtree.  Nor does it account for the merge window for net-next
being 2 months instead of dpdk's 6 months.  Theres no need in any way for 12
maintainers to be twiddling their thumbs waiting on ~20 patches each, and for
that split, you've forced developers to potentially develop patches against 12
trees (12 being the current number of PMD's that are in the dpdk).

The right answer here is balance.  Let me split out the pmd's and ethernet
infrastructure libraries to a subtree.  I'll pull in patches posted regarding
pmd's and librte_ether/ip_frag etc, and send you a pull requests after each
release so you get all the latest bits, and then pulls for stabilization on each
-rc. I can manage 300 patches without issue, and that takes a load off your
shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a single
alternate tree for developers to go to for pmd and pmd infrastructure updates.
Its a win-win.

Regards
Neil

Re: Why nothing since 1.8.0?

[O'driscoll, Tim]

> -----Original Message-----
> From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> Sent: Thursday, January 15, 2015 6:51 PM
> To: Thomas Monjalon
> Cc: dev-VfR2kkLFssw@public.gmane.org
> Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> 
> On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> > 2015-01-15 08:06, Neil Horman:
> > > On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon wrote:
> > > > 2015-01-15 04:27, Ouyang, Changchun:
> > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang, Helin
> > > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil
> Horman
> > > > > > > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger
> wrote:
> > > > > > > > Ok, so 1.8.0 came out almost a month ago and none of the
> patches
> > > > > > > > that were deferred waiting for the release got merged since
> then.
> > > > > > > > Last commit in git is the 1.8.0 release.
> > > > > > > >
> > > > > > > > Where is the post-merge window bundle, where are the later
> commits?
> > > > > > > > Lots of patches are sitting rotting in patchwork...
> > > > > > >
> > > > > > > +1, I've had the same questions.
> > > > > > > Neil
> > > > > >
> > > > > > +1, Some patch set might be ready for being merged.
> > > > >
> > > > > +1,  the earlier some patches are merged into mainline, and the easier
> those
> > > > > sequent patch sets can resolve their conflicts.
> > > >
> > > > +1, there are some patches which are properly reviewed
> > > >
> > > > Reminder: sub-tree to manage specific part of DPDK can be open on
> request
> > >
> > > Ok, I think what you're saying here is you're too busy to handle all the
> patches
> > > comming in at the moment.  As such I'd like to propose a sub-tree
> encompassing
> > > all the pmds in DPDK.  I would envision that including all the acutal pmd's
> in
> > > the tree, as well as the infrastructure that is used to interface them to the
> > > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
> > > and send you pull requests.
> >
> > The list of PMDs is increasing:
> > 	librte_pmd_af_packet
> > 	librte_pmd_bond
> > 	librte_pmd_e1000
> > 	librte_pmd_enic
> > 	librte_pmd_i40e
> > 	librte_pmd_ixgbe
> > 	librte_pmd_pcap
> > 	librte_pmd_ring
> > 	librte_pmd_virtio
> > 	librte_pmd_vmxnet3
> > 	librte_pmd_xenvirt
> > There is already some sub-trees for bnx2x, fm10k and i40e:
> > 	http://dpdk.org/browse/
> >
> Yes, and I've mentioned before that that is an absolutely silly way to break
> out
> subtrees.  You have to find a balance of workload distribution and developer
> convienience.
> 
> I also note that these are problematic because you're not merging anything
> from them. Is it your intention to keep bnx2 and fm10k separate in
> perpituity?
> If so, thats a real problem, because then we effectively just have several out
> of tree drivers, and thats just unacceptible.
> 
> > > If you could set me up with a login to dpdk.org, I'd appreciate it.
> >
> > It is preferred to have 1 sub-tree per module.
> > What do you think of managing contributions for af_packet and/or virtio?
> > It would make sense as virtio is a RedHat technology.
> > Maybe it could include vhost lib and example.
> >
> No, for reasons I've mentioned before.  If you take each pmd/library and
> create
> a subtree for it, you've created the most fine grained control of subtrees you
> could ask for, but you've created a nighmare of a burden on developers who
> want
> to update any code, especially if they have patches that hit multiple trees.
> 
> Look at some of the stats in the dpdk tree:
> 
> Library		Commits between 1.7.0 and 1.8.0
> librte_acl		5
> librte_cfgfile		0
> librte_cmdline		4
> librte_compat		0
> librte_distributor 	5
> librte_eal 		125
> librte_ether 		31
> librte_hash 		1
> librte_ip_frag 		5
> librte_ivshmem 		0
> librte_kni 		2
> librte_kvargs 		0
> librte_lpm 		1
> librte_malloc 		1
> librte_mbuf 		39
> librte_mempool 		4
> librte_meter 		0
> librte_net 		4
> librte_pipeline 	0
> librte_pmd_af_packet 	4
> librte_pmd_bond 	20
> librte_pmd_e1000 	21
> librte_pmd_enic 	12
> librte_pmd_i40e 	90
> librte_pmd_ixgbe 	83
> librte_pmd_pcap 	4
> librte_pmd_ring 	0
> librte_pmd_virtio 	21
> librte_pmd_vmxnet3 	21
> librte_pmd_xenvirt 	6
> librte_port 		6
> librte_power 		3
> librte_ring 		2
> librte_sched 		1
> librte_table 		7
> librte_timer 		0
> librte_vhost 		30
> 
> If you look at all of the pmds in the dpdk tree, we're talking about ~300
> patches per release.  If you look at the net-next tree for the linux kernel,
> Dave Miller merged 569 patches on his own (based on the following
> command:
> git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/ net/core/ |
> wc
> -l)
> 
> And that doesn't account for the ~500 patches that come in via pull request
> from
> the wireless subtree.  Nor does it account for the merge window for net-
> next
> being 2 months instead of dpdk's 6 months.  Theres no need in any way for
> 12
> maintainers to be twiddling their thumbs waiting on ~20 patches each, and
> for
> that split, you've forced developers to potentially develop patches against 12
> trees (12 being the current number of PMD's that are in the dpdk).
> 
> The right answer here is balance.  Let me split out the pmd's and ethernet
> infrastructure libraries to a subtree.  I'll pull in patches posted regarding
> pmd's and librte_ether/ip_frag etc, and send you a pull requests after each
> release so you get all the latest bits, and then pulls for stabilization on each
> -rc. I can manage 300 patches without issue, and that takes a load off your
> shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a single
> alternate tree for developers to go to for pmd and pmd infrastructure
> updates.
> Its a win-win.
> 
> Regards
> Neil

I agree with Thomas on this. The approach we've been taking for PMDs for newer Intel NICs is to have a separate sub-repository with a maintainer who's an expert in the area. This offloads some work from Thomas, ensures that the maintainer is very familiar with the PMD code and the corresponding hardware, and doesn't involve too much additional work for the developers involved (as you said, there isn't a huge volume of commits for any individual PMD). We have this in place for i40e now, and will be applying this to fm10k, which hasn't been upstreamed yet but will be in time for the 2.0 release. Based on our experiences with those, we may well look at extending the model to include PMDs for other Intel NICs, and possibly other libraries, as well.

As you said, there's a balance to be struck, and too many subtrees may become unmanageable. With respect to your concern about developers having to potentially develop patches against multiple subtrees, this has never been raised as a concern by any of our development team. Is there any historical data on the number of changes that would fall into this category so we can see if it's a real problem or not?


Tim

Re: Why nothing since 1.8.0?

[Matthew Hall]

On Thu, Jan 15, 2015 at 09:55:00PM +0000, O'driscoll, Tim wrote:
> As you said, there's a balance to be struck, and too many subtrees may 
> become unmanageable. With respect to your concern about developers having to 
> potentially develop patches against multiple subtrees, this has never been 
> raised as a concern by any of our development team. Is there any historical 
> data on the number of changes that would fall into this category so we can 
> see if it's a real problem or not?

Hi Tim,

What happens when a core API like rte_mbuf gets some changes, and you have to 
update the PMD's to fit?

Do I have to make 10-20 odd random patches to separate PMD maintainers instead 
of one set of patches to the PMD subtree?

To me it doesn't sound very nice for the guys maintaining the core. Given most 
of the changes seem to be mbuf or eal this seems like a scaling issue to me.

But maybe I misunderstood the process.

Matthew.

Re: Why nothing since 1.8.0?

[Thomas Monjalon]

2015-01-15 17:46, Matthew Hall:
> On Thu, Jan 15, 2015 at 09:55:00PM +0000, O'driscoll, Tim wrote:
> > As you said, there's a balance to be struck, and too many subtrees may 
> > become unmanageable. With respect to your concern about developers having to 
> > potentially develop patches against multiple subtrees, this has never been 
> > raised as a concern by any of our development team. Is there any historical 
> > data on the number of changes that would fall into this category so we can 
> > see if it's a real problem or not?
> 
> Hi Tim,
> 
> What happens when a core API like rte_mbuf gets some changes, and you have to 
> update the PMD's to fit?
> 
> Do I have to make 10-20 odd random patches to separate PMD maintainers instead 
> of one set of patches to the PMD subtree?

Then the patchset is core-wide and must be managed in the main tree.

> To me it doesn't sound very nice for the guys maintaining the core. Given most 
> of the changes seem to be mbuf or eal this seems like a scaling issue to me.

In previous release, there were a lot of changes related to i40e.
And we expect to have the same level of activity for fm10k.

> But maybe I misunderstood the process.

No problem, we are starting experiencing this model and will write some
guidelines.

-- 
Thomas

Re: Why nothing since 1.8.0?

[Neil Horman]

On Thu, Jan 15, 2015 at 09:55:00PM +0000, O'driscoll, Tim wrote:
> > -----Original Message-----
> > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> > Sent: Thursday, January 15, 2015 6:51 PM
> > To: Thomas Monjalon
> > Cc: dev-VfR2kkLFssw@public.gmane.org
> > Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> > 
> > On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> > > 2015-01-15 08:06, Neil Horman:
> > > > On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon wrote:
> > > > > 2015-01-15 04:27, Ouyang, Changchun:
> > > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang, Helin
> > > > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil
> > Horman
> > > > > > > > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger
> > wrote:
> > > > > > > > > Ok, so 1.8.0 came out almost a month ago and none of the
> > patches
> > > > > > > > > that were deferred waiting for the release got merged since
> > then.
> > > > > > > > > Last commit in git is the 1.8.0 release.
> > > > > > > > >
> > > > > > > > > Where is the post-merge window bundle, where are the later
> > commits?
> > > > > > > > > Lots of patches are sitting rotting in patchwork...
> > > > > > > >
> > > > > > > > +1, I've had the same questions.
> > > > > > > > Neil
> > > > > > >
> > > > > > > +1, Some patch set might be ready for being merged.
> > > > > >
> > > > > > +1,  the earlier some patches are merged into mainline, and the easier
> > those
> > > > > > sequent patch sets can resolve their conflicts.
> > > > >
> > > > > +1, there are some patches which are properly reviewed
> > > > >
> > > > > Reminder: sub-tree to manage specific part of DPDK can be open on
> > request
> > > >
> > > > Ok, I think what you're saying here is you're too busy to handle all the
> > patches
> > > > comming in at the moment.  As such I'd like to propose a sub-tree
> > encompassing
> > > > all the pmds in DPDK.  I would envision that including all the acutal pmd's
> > in
> > > > the tree, as well as the infrastructure that is used to interface them to the
> > > > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
> > > > and send you pull requests.
> > >
> > > The list of PMDs is increasing:
> > > 	librte_pmd_af_packet
> > > 	librte_pmd_bond
> > > 	librte_pmd_e1000
> > > 	librte_pmd_enic
> > > 	librte_pmd_i40e
> > > 	librte_pmd_ixgbe
> > > 	librte_pmd_pcap
> > > 	librte_pmd_ring
> > > 	librte_pmd_virtio
> > > 	librte_pmd_vmxnet3
> > > 	librte_pmd_xenvirt
> > > There is already some sub-trees for bnx2x, fm10k and i40e:
> > > 	http://dpdk.org/browse/
> > >
> > Yes, and I've mentioned before that that is an absolutely silly way to break
> > out
> > subtrees.  You have to find a balance of workload distribution and developer
> > convienience.
> > 
> > I also note that these are problematic because you're not merging anything
> > from them. Is it your intention to keep bnx2 and fm10k separate in
> > perpituity?
> > If so, thats a real problem, because then we effectively just have several out
> > of tree drivers, and thats just unacceptible.
> > 
> > > > If you could set me up with a login to dpdk.org, I'd appreciate it.
> > >
> > > It is preferred to have 1 sub-tree per module.
> > > What do you think of managing contributions for af_packet and/or virtio?
> > > It would make sense as virtio is a RedHat technology.
> > > Maybe it could include vhost lib and example.
> > >
> > No, for reasons I've mentioned before.  If you take each pmd/library and
> > create
> > a subtree for it, you've created the most fine grained control of subtrees you
> > could ask for, but you've created a nighmare of a burden on developers who
> > want
> > to update any code, especially if they have patches that hit multiple trees.
> > 
> > Look at some of the stats in the dpdk tree:
> > 
> > Library		Commits between 1.7.0 and 1.8.0
> > librte_acl		5
> > librte_cfgfile		0
> > librte_cmdline		4
> > librte_compat		0
> > librte_distributor 	5
> > librte_eal 		125
> > librte_ether 		31
> > librte_hash 		1
> > librte_ip_frag 		5
> > librte_ivshmem 		0
> > librte_kni 		2
> > librte_kvargs 		0
> > librte_lpm 		1
> > librte_malloc 		1
> > librte_mbuf 		39
> > librte_mempool 		4
> > librte_meter 		0
> > librte_net 		4
> > librte_pipeline 	0
> > librte_pmd_af_packet 	4
> > librte_pmd_bond 	20
> > librte_pmd_e1000 	21
> > librte_pmd_enic 	12
> > librte_pmd_i40e 	90
> > librte_pmd_ixgbe 	83
> > librte_pmd_pcap 	4
> > librte_pmd_ring 	0
> > librte_pmd_virtio 	21
> > librte_pmd_vmxnet3 	21
> > librte_pmd_xenvirt 	6
> > librte_port 		6
> > librte_power 		3
> > librte_ring 		2
> > librte_sched 		1
> > librte_table 		7
> > librte_timer 		0
> > librte_vhost 		30
> > 
> > If you look at all of the pmds in the dpdk tree, we're talking about ~300
> > patches per release.  If you look at the net-next tree for the linux kernel,
> > Dave Miller merged 569 patches on his own (based on the following
> > command:
> > git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/ net/core/ |
> > wc
> > -l)
> > 
> > And that doesn't account for the ~500 patches that come in via pull request
> > from
> > the wireless subtree.  Nor does it account for the merge window for net-
> > next
> > being 2 months instead of dpdk's 6 months.  Theres no need in any way for
> > 12
> > maintainers to be twiddling their thumbs waiting on ~20 patches each, and
> > for
> > that split, you've forced developers to potentially develop patches against 12
> > trees (12 being the current number of PMD's that are in the dpdk).
> > 
> > The right answer here is balance.  Let me split out the pmd's and ethernet
> > infrastructure libraries to a subtree.  I'll pull in patches posted regarding
> > pmd's and librte_ether/ip_frag etc, and send you a pull requests after each
> > release so you get all the latest bits, and then pulls for stabilization on each
> > -rc. I can manage 300 patches without issue, and that takes a load off your
> > shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a single
> > alternate tree for developers to go to for pmd and pmd infrastructure
> > updates.
> > Its a win-win.
> > 
> > Regards
> > Neil
> 
> I agree with Thomas on this. The approach we've been taking for PMDs for newer Intel NICs is to have a separate sub-repository with a maintainer who's an expert in the area. This offloads some work from Thomas, ensures that the maintainer is very familiar with the PMD code and the corresponding hardware, 
As I mentioned to you in a private note, you're convoluting two roles into a
single one here to the detriment of both:

1) A tree maintainer is a machine, who is responsible for the mechanicm of SCM
and tree maintenence.  They are responsible for merging patches, making sure
that merged patches make it to their upstream tree, ensuring conflicts get
resolved, and above all, making sure that SME's review patches before they get
merged

2) An SME (subject matter expert), is just that, someone who is intimately
familiar with the hardware and software of a certain bit of a project.  Their
only responsibility is to ensure that proposed changes are legitimate and safe.
They review patches within their purview and provide acks to the tree
maintainer.

When you merge these roles, you take the person most responsible for the
stability of their code, and distract them with 1000 patch management
operations, and from the work of developing new code for their area of
expertise.

The separation of these roles has evolved in several communities because of
exactly the above.  Linus knows alot about the kernel, but he's never opened the
I40e datasheet, and he doesn't have to because he trusts Dave M to ensure that
code in his pull requests is legitimate.  Dave in turn relies on someone at
Intel to ack every I40e patch on the list before he merges it.  He does exactly
the same thing with every single other sub-component as listed in the
MAINTAINERS file.  Thats how he is able to manage twice as many patches as the
dpdk can in half the amount of time.  If its efficiency you're after, thats the
route to go.  Please don't ignore all that evolutionary refinement.


>and doesn't involve too much additional work for the developers involved (as you said, there isn't a huge volume of commits for any individual PMD).
Patch volume isn't where the additional effort comes in.  Its in the
determination of what tree to develop against.

Lets take an example.  I'm doing work on the I40e card, so I have to look to see
if theres a separate tree for it.  I figure out there is, so I have to clone
that tree, and develop a patch against it.  So far so good.

A few days later I notice a bug in the pcap pmd, so I want to write a patch to
fix it.  If we carry your model out to the point where each pmd has its own
subtree, I have to go find that new tree, and clone it as well (or add a new
remote to my existing tree), pull those changes, branch from the proper master,
and continue my work).

If later I find a bug in the virtio pmd, I have to repeat the above process
again, cloning a new tree, or adding a new remote for that drivers tree.

It doesn't sound like alot when you're just sitting in a room talking about it,
but for the developers actually working on the code, its a significant
inconvienience, since it means that any pmd you want to touch requires you to go
through this lookup process, ensuring your branching from the right master
branch in the proper tree.

Conversely, if you put all pmds in a single subtree, it doesn't matter what
pmd a person is working on, they only have to clone the pmd subtree, and they're
good to go.


> We have this in place for i40e now, and will be applying this to fm10k, which hasn't been upstreamed yet but will be in time for the 2.0 release. Based on our experiences with those, we may well look at extending the model to include PMDs for other Intel NICs, and possibly other libraries, as well.
> 
You really haven't.  You have an i40e tree, but you have dozens of I40e patches
on the list, and all of them thus far have been integrated into the main tree.
Ditto with the bnx2x tree and others that have been separated.  Please remember
subject matter expert != repo maintainer.  The roles can be, and should be,
separeated.

> As you said, there's a balance to be struck, and too many subtrees may become unmanageable. With respect to your concern about developers having to potentially develop patches against multiple subtrees, this has never been raised as a concern by any of our development team. Is there any historical data on the number of changes that would fall into this category so we can see if it's a real problem or not?
Look at the linux kernel if you want historical data on where the balance is.
Major subsystems has become the natural breaking point for subtree maintenence.
Every net driver goes through Millers net or net-next tree.  All scsi updates go
through Bottomleys scsi tree.  FCoE changes used go through what used to be Rob
Loves FCoE tree.  It just makes sense.  I'm sure there isn't recorded data to
show anything more granular than that because no one ever seriously considered
breaking out all 301 network drivers into their own subtree, because its
obviously unmanageable at that scale. Even taken all as a single unit (as
the kernel does for network drivers), a single maintainer can still handle the
patch volume with the right subject matter experts doing timely reviews.


The point of this very long message is that maintainers != repos.  Just because
you're a subject matter expert in a given bit of hardware/pmd, in no way means
you need to be responsible for patch merging/maintenence.  Doing so just makes
everything harder.

Neil

Re: Why nothing since 1.8.0?

[O'driscoll, Tim]

I'm going to risk the wrath of the open source purists amongst you by top-posting. The reason is that there has been lots of email on this subject, and I want to summarise the key issue and clearly state our position on it. Hoperfully nobody is offended by this!

This thread has generated lots of debate, which is good, and there are a number of items that I believe everybody agrees on (having a MAINTAINERS file, better tools etc.). However, the key issue that we do not agree on is the granularity of the repositories within DPDK.

The current state is:
- One master repository
- A small number of sub-repositories, each with a separate maintainer/SME, including: i40e, fm10k, bnx2x, docs, dts. These are used to generate pull requests to the main repo.

You're proposing the following:
- Remove the individual PMD repositories, and replace them with a single repository containing all PMDs, plus parts of the core code that are closely linked to the PMDs, with you as the maintainer and SMEs for each PMD. 

As I've said before, and as Venky has also explained in private email on this, we do not agree with this proposed change. We believe it would be a backward step, and would have an adverse impact on DPDK.

The key issue here is that we've deliberately tried to give as much control as possible to those who are intimately familiar with a particular PMD and the underlying hardware. In our view, that's just common sense. What you're proposing is to take some of that control away, and give it to someone else (in this case you) who isn't familiar with the details. We don't agree with that approach.

The arguments I've heard in favour of your proposal are summarised below. Apologies for paraphrasing, and for any errors, but the email thread is too big and too convoluted to address these all separately. I've also included an explanation for each item to say why we don't believe they're sufficient to justify your proposed change.

1. Your proposal is consistent with the Linux kernel, but current state is not.
In both cases (current state and your proposal), the workflow is exactly the same as the Linux kernel. The difference we're discussing is simply the granularity of the repositories.

DPDK is much smaller than the kernel, so the granularity is naturally going to be different. The kernel may combine drivers into a single repository due to its size and complexity, but that doesn't mean we need to do the same for DPDK.

2. Maintainer and SME are separate roles and should not be combined.
We understand that they're separate roles. For the PMDs that we're developing, the most efficient way for us to manage the work is to combine these and have one of our SMEs act as maintainer as well. That's an internal decision that suits the structure of our development team and the current state of the i40e and fm10k PMDs. Others are obviously free to make their own choices for PMDs that they're developing.

3. A maintainer can handle a higher volume of patches than will be present in any individual PMD.
That's true, but it's also not relevant. Our goal is not to make the SME/maintainer for i40e, fm10k etc. a full-time position. Our goal is to have an expert in this position, so that we can move quickly and still ensure good quality software.

4. We shouldn't give maintainer work to an SME as it detracts from their other tasks.
We don't anticipate a problem with workload for the people that we have in these positions.

5. There will be extra overhead for developers who want to implement changes spanning multiple PMDs.
That's true, but it's also something of a hypothetical argument. The people who've spoken against your proposal on the mailing list are from Intel and 6Wind, who are also the people contributing to most of these PMDs. I had a quick scan of the commits to see if I could spot anything from another contributor that might fall into this category, and I couldn't (admittedly it wasn't an exhaustive search, which someone else is free to do if they want). If this situation does arise, then Thomas has previously outlined how it can be handled.


In terms of where we go from here, I'd suggest the following:
- Thomas has already asked us about a maintainer for older Intel NICs, which we're looking into. We may choose to have a single repository with a single maintainer/SME for e1000/igb/ixgbe combined, which would limit the overall number of repositories.
- You could pursue a path of having a single repository for non-Intel NICs. This would obviously need to be worked with those responsible (Stephen, Sujith etc.).
- As Thomas previously suggested, we should review this in future, possibly after 2.0. Maybe you'll be proven right and we'll all have to apologise for disagreeing!


Tim

> -----Original Message-----
> From: Neil Horman [mailto:nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org]
> Sent: Friday, January 16, 2015 4:51 PM
> To: O'driscoll, Tim
> Cc: Thomas Monjalon; dev-VfR2kkLFssw@public.gmane.org
> Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> 
> On Thu, Jan 15, 2015 at 09:55:00PM +0000, O'driscoll, Tim wrote:
> > > -----Original Message-----
> > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> > > Sent: Thursday, January 15, 2015 6:51 PM
> > > To: Thomas Monjalon
> > > Cc: dev-VfR2kkLFssw@public.gmane.org
> > > Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> > >
> > > On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> > > > 2015-01-15 08:06, Neil Horman:
> > > > > On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon wrote:
> > > > > > 2015-01-15 04:27, Ouyang, Changchun:
> > > > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang,
> Helin
> > > > > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil
> > > Horman
> > > > > > > > > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen
> Hemminger
> > > wrote:
> > > > > > > > > > Ok, so 1.8.0 came out almost a month ago and none of the
> > > patches
> > > > > > > > > > that were deferred waiting for the release got merged since
> > > then.
> > > > > > > > > > Last commit in git is the 1.8.0 release.
> > > > > > > > > >
> > > > > > > > > > Where is the post-merge window bundle, where are the
> later
> > > commits?
> > > > > > > > > > Lots of patches are sitting rotting in patchwork...
> > > > > > > > >
> > > > > > > > > +1, I've had the same questions.
> > > > > > > > > Neil
> > > > > > > >
> > > > > > > > +1, Some patch set might be ready for being merged.
> > > > > > >
> > > > > > > +1,  the earlier some patches are merged into mainline, and the
> easier
> > > those
> > > > > > > sequent patch sets can resolve their conflicts.
> > > > > >
> > > > > > +1, there are some patches which are properly reviewed
> > > > > >
> > > > > > Reminder: sub-tree to manage specific part of DPDK can be open on
> > > request
> > > > >
> > > > > Ok, I think what you're saying here is you're too busy to handle all the
> > > patches
> > > > > comming in at the moment.  As such I'd like to propose a sub-tree
> > > encompassing
> > > > > all the pmds in DPDK.  I would envision that including all the acutal
> pmd's
> > > in
> > > > > the tree, as well as the infrastructure that is used to interface them to
> the
> > > > > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch
> pool
> > > > > and send you pull requests.
> > > >
> > > > The list of PMDs is increasing:
> > > > 	librte_pmd_af_packet
> > > > 	librte_pmd_bond
> > > > 	librte_pmd_e1000
> > > > 	librte_pmd_enic
> > > > 	librte_pmd_i40e
> > > > 	librte_pmd_ixgbe
> > > > 	librte_pmd_pcap
> > > > 	librte_pmd_ring
> > > > 	librte_pmd_virtio
> > > > 	librte_pmd_vmxnet3
> > > > 	librte_pmd_xenvirt
> > > > There is already some sub-trees for bnx2x, fm10k and i40e:
> > > > 	http://dpdk.org/browse/
> > > >
> > > Yes, and I've mentioned before that that is an absolutely silly way to
> break
> > > out
> > > subtrees.  You have to find a balance of workload distribution and
> developer
> > > convienience.
> > >
> > > I also note that these are problematic because you're not merging
> anything
> > > from them. Is it your intention to keep bnx2 and fm10k separate in
> > > perpituity?
> > > If so, thats a real problem, because then we effectively just have several
> out
> > > of tree drivers, and thats just unacceptible.
> > >
> > > > > If you could set me up with a login to dpdk.org, I'd appreciate it.
> > > >
> > > > It is preferred to have 1 sub-tree per module.
> > > > What do you think of managing contributions for af_packet and/or
> virtio?
> > > > It would make sense as virtio is a RedHat technology.
> > > > Maybe it could include vhost lib and example.
> > > >
> > > No, for reasons I've mentioned before.  If you take each pmd/library and
> > > create
> > > a subtree for it, you've created the most fine grained control of subtrees
> you
> > > could ask for, but you've created a nighmare of a burden on developers
> who
> > > want
> > > to update any code, especially if they have patches that hit multiple
> trees.
> > >
> > > Look at some of the stats in the dpdk tree:
> > >
> > > Library		Commits between 1.7.0 and 1.8.0
> > > librte_acl		5
> > > librte_cfgfile		0
> > > librte_cmdline		4
> > > librte_compat		0
> > > librte_distributor 	5
> > > librte_eal 		125
> > > librte_ether 		31
> > > librte_hash 		1
> > > librte_ip_frag 		5
> > > librte_ivshmem 		0
> > > librte_kni 		2
> > > librte_kvargs 		0
> > > librte_lpm 		1
> > > librte_malloc 		1
> > > librte_mbuf 		39
> > > librte_mempool 		4
> > > librte_meter 		0
> > > librte_net 		4
> > > librte_pipeline 	0
> > > librte_pmd_af_packet 	4
> > > librte_pmd_bond 	20
> > > librte_pmd_e1000 	21
> > > librte_pmd_enic 	12
> > > librte_pmd_i40e 	90
> > > librte_pmd_ixgbe 	83
> > > librte_pmd_pcap 	4
> > > librte_pmd_ring 	0
> > > librte_pmd_virtio 	21
> > > librte_pmd_vmxnet3 	21
> > > librte_pmd_xenvirt 	6
> > > librte_port 		6
> > > librte_power 		3
> > > librte_ring 		2
> > > librte_sched 		1
> > > librte_table 		7
> > > librte_timer 		0
> > > librte_vhost 		30
> > >
> > > If you look at all of the pmds in the dpdk tree, we're talking about ~300
> > > patches per release.  If you look at the net-next tree for the linux kernel,
> > > Dave Miller merged 569 patches on his own (based on the following
> > > command:
> > > git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/
> net/core/ |
> > > wc
> > > -l)
> > >
> > > And that doesn't account for the ~500 patches that come in via pull
> request
> > > from
> > > the wireless subtree.  Nor does it account for the merge window for net-
> > > next
> > > being 2 months instead of dpdk's 6 months.  Theres no need in any way
> for
> > > 12
> > > maintainers to be twiddling their thumbs waiting on ~20 patches each,
> and
> > > for
> > > that split, you've forced developers to potentially develop patches
> against 12
> > > trees (12 being the current number of PMD's that are in the dpdk).
> > >
> > > The right answer here is balance.  Let me split out the pmd's and ethernet
> > > infrastructure libraries to a subtree.  I'll pull in patches posted regarding
> > > pmd's and librte_ether/ip_frag etc, and send you a pull requests after
> each
> > > release so you get all the latest bits, and then pulls for stabilization on
> each
> > > -rc. I can manage 300 patches without issue, and that takes a load off your
> > > shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a single
> > > alternate tree for developers to go to for pmd and pmd infrastructure
> > > updates.
> > > Its a win-win.
> > >
> > > Regards
> > > Neil
> >
> > I agree with Thomas on this. The approach we've been taking for PMDs for
> newer Intel NICs is to have a separate sub-repository with a maintainer
> who's an expert in the area. This offloads some work from Thomas, ensures
> that the maintainer is very familiar with the PMD code and the corresponding
> hardware,
> As I mentioned to you in a private note, you're convoluting two roles into a
> single one here to the detriment of both:
> 
> 1) A tree maintainer is a machine, who is responsible for the mechanicm of
> SCM
> and tree maintenence.  They are responsible for merging patches, making
> sure
> that merged patches make it to their upstream tree, ensuring conflicts get
> resolved, and above all, making sure that SME's review patches before they
> get
> merged
> 
> 2) An SME (subject matter expert), is just that, someone who is intimately
> familiar with the hardware and software of a certain bit of a project.  Their
> only responsibility is to ensure that proposed changes are legitimate and
> safe.
> They review patches within their purview and provide acks to the tree
> maintainer.
> 
> When you merge these roles, you take the person most responsible for the
> stability of their code, and distract them with 1000 patch management
> operations, and from the work of developing new code for their area of
> expertise.
> 
> The separation of these roles has evolved in several communities because of
> exactly the above.  Linus knows alot about the kernel, but he's never opened
> the
> I40e datasheet, and he doesn't have to because he trusts Dave M to ensure
> that
> code in his pull requests is legitimate.  Dave in turn relies on someone at
> Intel to ack every I40e patch on the list before he merges it.  He does exactly
> the same thing with every single other sub-component as listed in the
> MAINTAINERS file.  Thats how he is able to manage twice as many patches as
> the
> dpdk can in half the amount of time.  If its efficiency you're after, thats the
> route to go.  Please don't ignore all that evolutionary refinement.
> 
> 
> >and doesn't involve too much additional work for the developers involved
> (as you said, there isn't a huge volume of commits for any individual PMD).
> Patch volume isn't where the additional effort comes in.  Its in the
> determination of what tree to develop against.
> 
> Lets take an example.  I'm doing work on the I40e card, so I have to look to
> see
> if theres a separate tree for it.  I figure out there is, so I have to clone
> that tree, and develop a patch against it.  So far so good.
> 
> A few days later I notice a bug in the pcap pmd, so I want to write a patch to
> fix it.  If we carry your model out to the point where each pmd has its own
> subtree, I have to go find that new tree, and clone it as well (or add a new
> remote to my existing tree), pull those changes, branch from the proper
> master,
> and continue my work).
> 
> If later I find a bug in the virtio pmd, I have to repeat the above process
> again, cloning a new tree, or adding a new remote for that drivers tree.
> 
> It doesn't sound like alot when you're just sitting in a room talking about it,
> but for the developers actually working on the code, its a significant
> inconvienience, since it means that any pmd you want to touch requires you
> to go
> through this lookup process, ensuring your branching from the right master
> branch in the proper tree.
> 
> Conversely, if you put all pmds in a single subtree, it doesn't matter what
> pmd a person is working on, they only have to clone the pmd subtree, and
> they're
> good to go.
> 
> 
> > We have this in place for i40e now, and will be applying this to fm10k, which
> hasn't been upstreamed yet but will be in time for the 2.0 release. Based on
> our experiences with those, we may well look at extending the model to
> include PMDs for other Intel NICs, and possibly other libraries, as well.
> >
> You really haven't.  You have an i40e tree, but you have dozens of I40e
> patches
> on the list, and all of them thus far have been integrated into the main tree.
> Ditto with the bnx2x tree and others that have been separated.  Please
> remember
> subject matter expert != repo maintainer.  The roles can be, and should be,
> separeated.
> 
> > As you said, there's a balance to be struck, and too many subtrees may
> become unmanageable. With respect to your concern about developers
> having to potentially develop patches against multiple subtrees, this has
> never been raised as a concern by any of our development team. Is there
> any historical data on the number of changes that would fall into this
> category so we can see if it's a real problem or not?
> Look at the linux kernel if you want historical data on where the balance is.
> Major subsystems has become the natural breaking point for subtree
> maintenence.
> Every net driver goes through Millers net or net-next tree.  All scsi updates
> go
> through Bottomleys scsi tree.  FCoE changes used go through what used to
> be Rob
> Loves FCoE tree.  It just makes sense.  I'm sure there isn't recorded data to
> show anything more granular than that because no one ever seriously
> considered
> breaking out all 301 network drivers into their own subtree, because its
> obviously unmanageable at that scale. Even taken all as a single unit (as
> the kernel does for network drivers), a single maintainer can still handle the
> patch volume with the right subject matter experts doing timely reviews.
> 
> 
> The point of this very long message is that maintainers != repos.  Just
> because
> you're a subject matter expert in a given bit of hardware/pmd, in no way
> means
> you need to be responsible for patch merging/maintenence.  Doing so just
> makes
> everything harder.
> 
> Neil

Re: Why nothing since 1.8.0?

[Stephen Hemminger]

I am all for having multiple staging trees that get MERGED into one
upstream tree.

Let me make it simple, no out of tree drivers. I am not supporting,
maintaining or submitting drivers that
are not in the mainline DPDK product. If you want me to submit drivers,
then they should go into
the mainstream.

Developers:
Want to be able to make changes to core infrastructure during merge window
and fix all the
related drivers. For many devices, developer wants to be able to submit a
driver and have it
fixed by others in the main tree.

Vendors:
Want to be able to extend, change, and enhance the existing DPDK tree and
then build an application
with that. It is a increase in technical overhead to merge in drivers from
multiple sources.

Re: Why nothing since 1.8.0?

[Neil Horman]

On Sat, Jan 17, 2015 at 07:57:04PM +0000, O'driscoll, Tim wrote:
> I'm going to risk the wrath of the open source purists amongst you by top-posting. The reason is that there has been lots of email on this subject, and I want to summarise the key issue and clearly state our position on it. Hoperfully nobody is offended by this!
> 
Acutally, I am a bit upset by your doing this.  While top posting can be an
acceptible response form, doing so in an interleaved thread gives you the
opportunity to effectively rewrite the conversation on your own terms.  While
you might have summarized your position accurately in your mind, you've
discarded all the evidence that I presented in opposition.  I don't appreciate
that.  But we can rebuild from here, no worries.

> This thread has generated lots of debate, which is good, and there are a number of items that I believe everybody agrees on (having a MAINTAINERS file, better tools etc.). However, the key issue that we do not agree on is the granularity of the repositories within DPDK.
> 
No, thats not really the crux of the debate in my mind anymore, though that is
certainly part of it, as it effects the convienience of developers to contribute
to the project.  More to the point, the area of disagreement here is the best,
most efficient way to integrate patches to various pieces of the dpdk that
balances developer convienience, effiency and transparency (I've not ennumerated
that last part before, as I've not thought of the right word, and that may still
not be quite right, but more on it later).

> The current state is:
> - One master repository
> - A small number of sub-repositories, each with a separate maintainer/SME, including: i40e, fm10k, bnx2x, docs, dts. These are used to generate pull requests to the main repo.
> 
No, this is not the current state.  The current state is:
- One master repository

We have lots of cloned dpdk trees on dpdk.org, but there is no path from them to
the master repository.  Nothing has been comitted to any of the subtrees,
despite having been open for a few months now.  I don't see any documentation
indicating who the maintainer of each tree is, and so don't have the foggiest
idea who to contact if I want to get something merged to these trees.  They
aren't subtrees, they're just clones of the master repository.

> You're proposing the following:
> - Remove the individual PMD repositories, and replace them with a single repository containing all PMDs, plus parts of the core code that are closely linked to the PMDs, with you as the maintainer and SMEs for each PMD. 
> 
Not necesarily me, mind you (though yes, I've volunteered).  I'm happy for
someone else to take on this role if they volunteer.  The point is not to have a
separate repo to integrate patches for any one PMD (as theres no need, and it
makes development harder).  I want one repository that I can use to target
development against all PMDs, just like we do with net/net-next in the linux
community.

> As I've said before, and as Venky has also explained in private email on this, we do not agree with this proposed change. We believe it would be a backward step, and would have an adverse impact on DPDK.
> 
You've asserted that several times, but not once have you provided any
supporting evidence or data to back that assertion.  Conversely I've provided
several bits of evidence to support my assertion that using the linux workflow
model would work perfectly well here and handle all our needs (which include,
but are not limited to, yours).

> The key issue here is that we've deliberately tried to give as much control as possible to those who are intimately familiar with a particular PMD and the underlying hardware. In our view, that's just common sense. What you're proposing is to take some of that control away, and give it to someone else (in this case you) who isn't familiar with the details. We don't agree with that approach.
> 
Yes, you have proposed that.  The question is, why?  People intimately familiar
with the code should be writing and reviewing code.  Why do they need the
responsibility for integration as well?  Thats really the question.  Answer
that, and perhaps we can make some process on this issue.  Tell me how one of
the people most familiar with a given piece of hardware and the software that
drives it having the added responsibility of handling the trivial operations of
SCM helps you, or anyone else?  I'll point out again here that there are 6 I40e
patches on the DPDK list, some as old as November 20th of last year.  4 have
been ACK'd, but none have been integrated, with no additional commentary from
the experts who are tasked with the patch management role.  How is that
efficient, transparent or condusive to development?


> The arguments I've heard in favour of your proposal are summarised below. Apologies for paraphrasing, and for any errors, but the email thread is too big and too convoluted to address these all separately. I've also included an explanation for each item to say why we don't believe they're sufficient to justify your proposed change.
> 
I thought we were doing just fine with the conversation.  The paraphrasing here
is why I was upset by your top post.  You convieniently ignored all my
supporting evidence.

> 1. Your proposal is consistent with the Linux kernel, but current state is not.
> In both cases (current state and your proposal), the workflow is exactly the same as the Linux kernel. The difference we're discussing is simply the granularity of the repositories.
> 
Thats simply not true.  My proposal is consistent with the linux kernel model,
but what you want in no way is.  The graunularity is diffferent as you note, but
you're adding in this requirement whereby a developer for a given PMD must be
the tree maintainer for a subtree solely for the purpose of maintaining that
PMD.  That in no way shape or form resembles the linux kernel model.  If you
wish to do that internally to Intel, thats great, and you have all the ability
to do that, but to mandate it as part of the community project is anathema to
the way the linux workflow works, and open source projects in general.

> DPDK is much smaller than the kernel, so the granularity is naturally going to be different. The kernel may combine drivers into a single repository due to its size and complexity, but that doesn't mean we need to do the same for DPDK.
> 
Why?  You're right in the most general of senses, diffferent projects can work 
differently, but being different in one way (size/complexity), doesn't mandate
that it be different in another way (workflow).  We can (and are) exploring
different ways to implement workflows here, but the question is one of reason.
The kernel combines drivers into a single respository because its a natural
functional separation that allows Linus to divide the workload to subordinates,
while still giving contributing developers a canonical place to go for their
development target needs.  Its efficient (As I calculated before in the
interleaved section below, Dave Miller integrates either from pull requests or
individual posts, over 1000 patches on average every 2 month release cycle),
fast (even though every patch goes to the mailing list, gets reviewed, and
acked), and convienient for all developers.

Conversely, the I40e driver has seen 114 patches in the last 6 month period to
the DPDK.  What is it about dpdk PMD's that makes a process that is as  
efficient, fast and transparent as the upstream kenrel's unacceptible to you?
 
> 2. Maintainer and SME are separate roles and should not be combined.
> We understand that they're separate roles. For the PMDs that we're developing, the most efficient way for us to manage the work is to combine these and have one of our SMEs act as maintainer as well. That's an internal decision that suits the structure of our development team and the current state of the i40e and fm10k PMDs. Others are obviously free to make their own choices for PMDs that they're developing.
> 
Thats a really interesting thing to say.  You made an internal decision,  but
this isn't an internal project.  This is a community project.  If you want an
internal tree to commit patches too, thats fine, you can and should do that for
whatever internal workflow suits your needs, but before they get merged to the
community project (which includes the I40e driver), they need to get posted to
the community list to allow any and all an opportunity to review them (even if
they choose not to, they deserve the opportunity).  It seems that, while you
haven't said it in so many words, you are looking for ways to accelerate that
process, and potentially cutting out the community in the process.

Let me ask a question here: Do you intend to post all the I40e patches that you
plan to commit to the I40e tree to the DPDK list?  Or do you plan to integrate
them to the tree using only internal review, and then send a pull request to the
list?  If you are planning on doing the latter, that would explain your desires
to merge the tree maintainer and SME role, but would be a huge step backwards
from all of the progress you've made toward making this project a true community
project.  As Stephen indicates, what you're then doing is creating several
out-of-tree drivers, and that would be totally unacceptable.  You're of course
welcome to do so, but I would not accept any workflow in which changes to code
did not have patches posted to the list.

> 3. A maintainer can handle a higher volume of patches than will be present in any individual PMD.
> That's true, but it's also not relevant. Our goal is not to make the SME/maintainer for i40e, fm10k etc. a full-time position. Our goal is to have an expert in this position, so that we can move quickly and still ensure good quality software.
> 
Please re-read your above statement. I think you're contradicting yourself
1) You agree that a tree maintainer can handle a higher volume of patches than
any one PMD presents, implying that a tree maintainer can, when properly
focused, efficiently take the feedback of SME's and integrate many patches
quickly.

2) You claim (1) is irellevant because because your goal is to put an expert in
the position of tree maintainer so that you can move more quickly.

If you agree that (1) allows for a fast, efficient and transparent workflow, how
can you both claim it is both irrelevant and that you need a merged SME/tree
maintainer role to achieve the same goal?

Question: How exactly do you believe putting an SME in the role of tree
maintainer will improve code quality and make code integration faster?

> 4. We shouldn't give maintainer work to an SME as it detracts from their other tasks.
> We don't anticipate a problem with workload for the people that we have in these positions.
You're having that problem right now, you just refuse to acknoweldge it.  Let me
present it for you:
http://dpdk.org/dev/patchwork/project/dpdk/list/?q=I40e

That shows the only 6 patches that have been posted for I40e since 1.8 released,
ranging dating back as far as November 20th.  These patches have been sittting
on the list since then unacted upon.  If fact, taking a closer look, its a bit
worse than that.  The X710 patch in that list has been integrated, but a version
different from the one in patchwork.  Its probably just an oversight, but the
fact remains, whoever is doing your subtree maintenence is focused on your
internal needs and is ignoring their community responsibilities.  Thats a
problem.


> 
> 5. There will be extra overhead for developers who want to implement changes spanning multiple PMDs.
> That's true, but it's also something of a hypothetical argument. The people who've spoken against your proposal on the mailing list are from Intel and 6Wind, who are also the people contributing to most of these PMDs. I had a quick scan of the commits to see if I could spot anything from another contributor that might fall into this category, and I couldn't (admittedly it wasn't an exhaustive search, which someone else is free to do if they want). If this situation does arise, then Thomas has previously outlined how it can be handled.

Its not a hypothetical argument at all.  We have this situation upstream every
time someone makes a patch that crosses subsystems, and its managed by the
maintainers co-ordinating their efforts when merge time comes along.  Thats why
its so important to find the right granularity for subtrees, so that extra
effort is minimized.

And yes, you're right, most of the contributors currently are from 6wind and
Intel.  The goal here is to spread that participation beyond just the two of
you.  If you don't have a tree-maintainer that is actively handling patches on
the list, getting things integrated in a timely fashion, no one is going to
bother participating.

As for handling it using the workaround thomas has proposed, I've made my
arguments to that effect already several times, but you've neglected to
summarize them here with your top post, so let me re-iterate:
Patch sets that cross subtrees are a challenge no matter how you slice them.  If
you have subtrees at a reasonable granularity, subtree maintainers can work
together to ensure that the upstream merge goes smoothly.  If you force a tree
spanning patch to be done in the parent tree you will have merge work to do for
each subtree that sends you a pull request.  Having a few subtree maintainers
handle that work is preferable than having to do merge fixups in the main tree.
The main tree should whenever possible have clean merges.

> 
> 
> In terms of where we go from here, I'd suggest the following:
> - Thomas has already asked us about a maintainer for older Intel NICs, which we're looking into. We may choose to have a single repository with a single maintainer/SME for e1000/igb/ixgbe combined, which would limit the overall number of repositories.
> - You could pursue a path of having a single repository for non-Intel NICs. This would obviously need to be worked with those responsible (Stephen, Sujith etc.).
> - As Thomas previously suggested, we should review this in future, possibly after 2.0. Maybe you'll be proven right and we'll all have to apologise for disagreeing!

It sounds like you've already made a decision.  Thats really disheartening.
You've gone to alot of effort to make this project more open, and I'd like to
encourage you further in that direction.  But your comments above really make
me think that you're hoping to isolate your development efforts, which is a step
in the wrong direction. 

Neil


> > -----Original Message-----
> > From: Neil Horman [mailto:nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org]
> > Sent: Friday, January 16, 2015 4:51 PM
> > To: O'driscoll, Tim
> > Cc: Thomas Monjalon; dev-VfR2kkLFssw@public.gmane.org
> > Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> > 
> > On Thu, Jan 15, 2015 at 09:55:00PM +0000, O'driscoll, Tim wrote:
> > > > -----Original Message-----
> > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> > > > Sent: Thursday, January 15, 2015 6:51 PM
> > > > To: Thomas Monjalon
> > > > Cc: dev-VfR2kkLFssw@public.gmane.org
> > > > Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> > > >
> > > > On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> > > > > 2015-01-15 08:06, Neil Horman:
> > > > > > On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon wrote:
> > > > > > > 2015-01-15 04:27, Ouyang, Changchun:
> > > > > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang,
> > Helin
> > > > > > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil
> > > > Horman
> > > > > > > > > > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen
> > Hemminger
> > > > wrote:
> > > > > > > > > > > Ok, so 1.8.0 came out almost a month ago and none of the
> > > > patches
> > > > > > > > > > > that were deferred waiting for the release got merged since
> > > > then.
> > > > > > > > > > > Last commit in git is the 1.8.0 release.
> > > > > > > > > > >
> > > > > > > > > > > Where is the post-merge window bundle, where are the
> > later
> > > > commits?
> > > > > > > > > > > Lots of patches are sitting rotting in patchwork...
> > > > > > > > > >
> > > > > > > > > > +1, I've had the same questions.
> > > > > > > > > > Neil
> > > > > > > > >
> > > > > > > > > +1, Some patch set might be ready for being merged.
> > > > > > > >
> > > > > > > > +1,  the earlier some patches are merged into mainline, and the
> > easier
> > > > those
> > > > > > > > sequent patch sets can resolve their conflicts.
> > > > > > >
> > > > > > > +1, there are some patches which are properly reviewed
> > > > > > >
> > > > > > > Reminder: sub-tree to manage specific part of DPDK can be open on
> > > > request
> > > > > >
> > > > > > Ok, I think what you're saying here is you're too busy to handle all the
> > > > patches
> > > > > > comming in at the moment.  As such I'd like to propose a sub-tree
> > > > encompassing
> > > > > > all the pmds in DPDK.  I would envision that including all the acutal
> > pmd's
> > > > in
> > > > > > the tree, as well as the infrastructure that is used to interface them to
> > the
> > > > > > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch
> > pool
> > > > > > and send you pull requests.
> > > > >
> > > > > The list of PMDs is increasing:
> > > > > 	librte_pmd_af_packet
> > > > > 	librte_pmd_bond
> > > > > 	librte_pmd_e1000
> > > > > 	librte_pmd_enic
> > > > > 	librte_pmd_i40e
> > > > > 	librte_pmd_ixgbe
> > > > > 	librte_pmd_pcap
> > > > > 	librte_pmd_ring
> > > > > 	librte_pmd_virtio
> > > > > 	librte_pmd_vmxnet3
> > > > > 	librte_pmd_xenvirt
> > > > > There is already some sub-trees for bnx2x, fm10k and i40e:
> > > > > 	http://dpdk.org/browse/
> > > > >
> > > > Yes, and I've mentioned before that that is an absolutely silly way to
> > break
> > > > out
> > > > subtrees.  You have to find a balance of workload distribution and
> > developer
> > > > convienience.
> > > >
> > > > I also note that these are problematic because you're not merging
> > anything
> > > > from them. Is it your intention to keep bnx2 and fm10k separate in
> > > > perpituity?
> > > > If so, thats a real problem, because then we effectively just have several
> > out
> > > > of tree drivers, and thats just unacceptible.
> > > >
> > > > > > If you could set me up with a login to dpdk.org, I'd appreciate it.
> > > > >
> > > > > It is preferred to have 1 sub-tree per module.
> > > > > What do you think of managing contributions for af_packet and/or
> > virtio?
> > > > > It would make sense as virtio is a RedHat technology.
> > > > > Maybe it could include vhost lib and example.
> > > > >
> > > > No, for reasons I've mentioned before.  If you take each pmd/library and
> > > > create
> > > > a subtree for it, you've created the most fine grained control of subtrees
> > you
> > > > could ask for, but you've created a nighmare of a burden on developers
> > who
> > > > want
> > > > to update any code, especially if they have patches that hit multiple
> > trees.
> > > >
> > > > Look at some of the stats in the dpdk tree:
> > > >
> > > > Library		Commits between 1.7.0 and 1.8.0
> > > > librte_acl		5
> > > > librte_cfgfile		0
> > > > librte_cmdline		4
> > > > librte_compat		0
> > > > librte_distributor 	5
> > > > librte_eal 		125
> > > > librte_ether 		31
> > > > librte_hash 		1
> > > > librte_ip_frag 		5
> > > > librte_ivshmem 		0
> > > > librte_kni 		2
> > > > librte_kvargs 		0
> > > > librte_lpm 		1
> > > > librte_malloc 		1
> > > > librte_mbuf 		39
> > > > librte_mempool 		4
> > > > librte_meter 		0
> > > > librte_net 		4
> > > > librte_pipeline 	0
> > > > librte_pmd_af_packet 	4
> > > > librte_pmd_bond 	20
> > > > librte_pmd_e1000 	21
> > > > librte_pmd_enic 	12
> > > > librte_pmd_i40e 	90
> > > > librte_pmd_ixgbe 	83
> > > > librte_pmd_pcap 	4
> > > > librte_pmd_ring 	0
> > > > librte_pmd_virtio 	21
> > > > librte_pmd_vmxnet3 	21
> > > > librte_pmd_xenvirt 	6
> > > > librte_port 		6
> > > > librte_power 		3
> > > > librte_ring 		2
> > > > librte_sched 		1
> > > > librte_table 		7
> > > > librte_timer 		0
> > > > librte_vhost 		30
> > > >
> > > > If you look at all of the pmds in the dpdk tree, we're talking about ~300
> > > > patches per release.  If you look at the net-next tree for the linux kernel,
> > > > Dave Miller merged 569 patches on his own (based on the following
> > > > command:
> > > > git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/
> > net/core/ |
> > > > wc
> > > > -l)
> > > >
> > > > And that doesn't account for the ~500 patches that come in via pull
> > request
> > > > from
> > > > the wireless subtree.  Nor does it account for the merge window for net-
> > > > next
> > > > being 2 months instead of dpdk's 6 months.  Theres no need in any way
> > for
> > > > 12
> > > > maintainers to be twiddling their thumbs waiting on ~20 patches each,
> > and
> > > > for
> > > > that split, you've forced developers to potentially develop patches
> > against 12
> > > > trees (12 being the current number of PMD's that are in the dpdk).
> > > >
> > > > The right answer here is balance.  Let me split out the pmd's and ethernet
> > > > infrastructure libraries to a subtree.  I'll pull in patches posted regarding
> > > > pmd's and librte_ether/ip_frag etc, and send you a pull requests after
> > each
> > > > release so you get all the latest bits, and then pulls for stabilization on
> > each
> > > > -rc. I can manage 300 patches without issue, and that takes a load off your
> > > > shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a single
> > > > alternate tree for developers to go to for pmd and pmd infrastructure
> > > > updates.
> > > > Its a win-win.
> > > >
> > > > Regards
> > > > Neil
> > >
> > > I agree with Thomas on this. The approach we've been taking for PMDs for
> > newer Intel NICs is to have a separate sub-repository with a maintainer
> > who's an expert in the area. This offloads some work from Thomas, ensures
> > that the maintainer is very familiar with the PMD code and the corresponding
> > hardware,
> > As I mentioned to you in a private note, you're convoluting two roles into a
> > single one here to the detriment of both:
> > 
> > 1) A tree maintainer is a machine, who is responsible for the mechanicm of
> > SCM
> > and tree maintenence.  They are responsible for merging patches, making
> > sure
> > that merged patches make it to their upstream tree, ensuring conflicts get
> > resolved, and above all, making sure that SME's review patches before they
> > get
> > merged
> > 
> > 2) An SME (subject matter expert), is just that, someone who is intimately
> > familiar with the hardware and software of a certain bit of a project.  Their
> > only responsibility is to ensure that proposed changes are legitimate and
> > safe.
> > They review patches within their purview and provide acks to the tree
> > maintainer.
> > 
> > When you merge these roles, you take the person most responsible for the
> > stability of their code, and distract them with 1000 patch management
> > operations, and from the work of developing new code for their area of
> > expertise.
> > 
> > The separation of these roles has evolved in several communities because of
> > exactly the above.  Linus knows alot about the kernel, but he's never opened
> > the
> > I40e datasheet, and he doesn't have to because he trusts Dave M to ensure
> > that
> > code in his pull requests is legitimate.  Dave in turn relies on someone at
> > Intel to ack every I40e patch on the list before he merges it.  He does exactly
> > the same thing with every single other sub-component as listed in the
> > MAINTAINERS file.  Thats how he is able to manage twice as many patches as
> > the
> > dpdk can in half the amount of time.  If its efficiency you're after, thats the
> > route to go.  Please don't ignore all that evolutionary refinement.
> > 
> > 
> > >and doesn't involve too much additional work for the developers involved
> > (as you said, there isn't a huge volume of commits for any individual PMD).
> > Patch volume isn't where the additional effort comes in.  Its in the
> > determination of what tree to develop against.
> > 
> > Lets take an example.  I'm doing work on the I40e card, so I have to look to
> > see
> > if theres a separate tree for it.  I figure out there is, so I have to clone
> > that tree, and develop a patch against it.  So far so good.
> > 
> > A few days later I notice a bug in the pcap pmd, so I want to write a patch to
> > fix it.  If we carry your model out to the point where each pmd has its own
> > subtree, I have to go find that new tree, and clone it as well (or add a new
> > remote to my existing tree), pull those changes, branch from the proper
> > master,
> > and continue my work).
> > 
> > If later I find a bug in the virtio pmd, I have to repeat the above process
> > again, cloning a new tree, or adding a new remote for that drivers tree.
> > 
> > It doesn't sound like alot when you're just sitting in a room talking about it,
> > but for the developers actually working on the code, its a significant
> > inconvienience, since it means that any pmd you want to touch requires you
> > to go
> > through this lookup process, ensuring your branching from the right master
> > branch in the proper tree.
> > 
> > Conversely, if you put all pmds in a single subtree, it doesn't matter what
> > pmd a person is working on, they only have to clone the pmd subtree, and
> > they're
> > good to go.
> > 
> > 
> > > We have this in place for i40e now, and will be applying this to fm10k, which
> > hasn't been upstreamed yet but will be in time for the 2.0 release. Based on
> > our experiences with those, we may well look at extending the model to
> > include PMDs for other Intel NICs, and possibly other libraries, as well.
> > >
> > You really haven't.  You have an i40e tree, but you have dozens of I40e
> > patches
> > on the list, and all of them thus far have been integrated into the main tree.
> > Ditto with the bnx2x tree and others that have been separated.  Please
> > remember
> > subject matter expert != repo maintainer.  The roles can be, and should be,
> > separeated.
> > 
> > > As you said, there's a balance to be struck, and too many subtrees may
> > become unmanageable. With respect to your concern about developers
> > having to potentially develop patches against multiple subtrees, this has
> > never been raised as a concern by any of our development team. Is there
> > any historical data on the number of changes that would fall into this
> > category so we can see if it's a real problem or not?
> > Look at the linux kernel if you want historical data on where the balance is.
> > Major subsystems has become the natural breaking point for subtree
> > maintenence.
> > Every net driver goes through Millers net or net-next tree.  All scsi updates
> > go
> > through Bottomleys scsi tree.  FCoE changes used go through what used to
> > be Rob
> > Loves FCoE tree.  It just makes sense.  I'm sure there isn't recorded data to
> > show anything more granular than that because no one ever seriously
> > considered
> > breaking out all 301 network drivers into their own subtree, because its
> > obviously unmanageable at that scale. Even taken all as a single unit (as
> > the kernel does for network drivers), a single maintainer can still handle the
> > patch volume with the right subject matter experts doing timely reviews.
> > 
> > 
> > The point of this very long message is that maintainers != repos.  Just
> > because
> > you're a subject matter expert in a given bit of hardware/pmd, in no way
> > means
> > you need to be responsible for patch merging/maintenence.  Doing so just
> > makes
> > everything harder.
> > 
> > Neil
> 
> 

Re: Why nothing since 1.8.0?

[O'driscoll, Tim]

> -----Original Message-----
> From: Neil Horman [mailto:nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org]
> Sent: Sunday, January 18, 2015 6:25 PM
> To: O'driscoll, Tim
> Cc: Thomas Monjalon; dev-VfR2kkLFssw@public.gmane.org
> Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> 
> On Sat, Jan 17, 2015 at 07:57:04PM +0000, O'driscoll, Tim wrote:
> > I'm going to risk the wrath of the open source purists amongst you by top-
> posting. The reason is that there has been lots of email on this subject, and I
> want to summarise the key issue and clearly state our position on it.
> Hoperfully nobody is offended by this!
> >
> Acutally, I am a bit upset by your doing this.  While top posting can be an
> acceptible response form, doing so in an interleaved thread gives you the
> opportunity to effectively rewrite the conversation on your own terms.
> While
> you might have summarized your position accurately in your mind, you've
> discarded all the evidence that I presented in opposition.  I don't appreciate
> that.  But we can rebuild from here, no worries.
> 
> > This thread has generated lots of debate, which is good, and there are a
> number of items that I believe everybody agrees on (having a MAINTAINERS
> file, better tools etc.). However, the key issue that we do not agree on is the
> granularity of the repositories within DPDK.
> >
> No, thats not really the crux of the debate in my mind anymore, though that
> is
> certainly part of it, as it effects the convienience of developers to contribute
> to the project.  More to the point, the area of disagreement here is the best,
> most efficient way to integrate patches to various pieces of the dpdk that
> balances developer convienience, effiency and transparency (I've not
> ennumerated
> that last part before, as I've not thought of the right word, and that may still
> not be quite right, but more on it later).
> 
> > The current state is:
> > - One master repository
> > - A small number of sub-repositories, each with a separate
> maintainer/SME, including: i40e, fm10k, bnx2x, docs, dts. These are used to
> generate pull requests to the main repo.
> >
> No, this is not the current state.  The current state is:
> - One master repository

We have a repository for docs, with a separate maintainer that was used to generate pull requests for 1.8. From our perspective that worked well.
For i40e, 1.8 development was done in the main repository, and we agreed to transition to a separate repo for 2.0. 2.0 development is currently in progress.
We haven't upstreamed anything for fm10k yet, but that will be done in its own repo from the start, for the 2.0 release.

> We have lots of cloned dpdk trees on dpdk.org, but there is no path from
> them to
> the master repository.  Nothing has been comitted to any of the subtrees,
> despite having been open for a few months now.

The plan is to use the i40e and fm10k repos for 2.0 development, which is in progress.

>  I don't see any
> documentation
> indicating who the maintainer of each tree is, and so don't have the foggiest
> idea who to contact if I want to get something merged to these trees.  They
> aren't subtrees, they're just clones of the master repository.

A MAINTAINERS file to clarify responsibilities is a good idea.

> > You're proposing the following:
> > - Remove the individual PMD repositories, and replace them with a single
> repository containing all PMDs, plus parts of the core code that are closely
> linked to the PMDs, with you as the maintainer and SMEs for each PMD.
> >
> Not necesarily me, mind you (though yes, I've volunteered).  I'm happy for
> someone else to take on this role if they volunteer.  The point is not to have
> a
> separate repo to integrate patches for any one PMD (as theres no need, and
> it
> makes development harder).  I want one repository that I can use to target
> development against all PMDs, just like we do with net/net-next in the linux
> community.
> 
> > As I've said before, and as Venky has also explained in private email on this,
> we do not agree with this proposed change. We believe it would be a
> backward step, and would have an adverse impact on DPDK.
> >
> You've asserted that several times, but not once have you provided any
> supporting evidence or data to back that assertion.  Conversely I've provided
> several bits of evidence to support my assertion that using the linux
> workflow
> model would work perfectly well here and handle all our needs (which
> include,
> but are not limited to, yours).

The reason is to give as much control as possible to the people most familiar with the PMD code and the corresponding NIC hardware.

> > The key issue here is that we've deliberately tried to give as much control
> as possible to those who are intimately familiar with a particular PMD and the
> underlying hardware. In our view, that's just common sense. What you're
> proposing is to take some of that control away, and give it to someone else
> (in this case you) who isn't familiar with the details. We don't agree with that
> approach.
> >
> Yes, you have proposed that.  The question is, why?  People intimately
> familiar
> with the code should be writing and reviewing code.  Why do they need the
> responsibility for integration as well?  Thats really the question.  Answer
> that, and perhaps we can make some process on this issue.  Tell me how one
> of
> the people most familiar with a given piece of hardware and the software
> that
> drives it having the added responsibility of handling the trivial operations of
> SCM helps you, or anyone else?  I'll point out again here that there are 6 I40e
> patches on the DPDK list, some as old as November 20th of last year.  4 have
> been ACK'd, but none have been integrated, with no additional commentary
> from
> the experts who are tasked with the patch management role.  How is that
> efficient, transparent or condusive to development?

We're doing a lot of work on i40e and fm10k at the moment. In both cases, somebody needs to fill the maintainer role. That could be someone familiar with the PMD code and NIC hardware, or it could be somebody without this depth of knowledge. The current situation is the first option. It's true that it doesn't have to be done that way, but it seems sensible to give as much control as possible to the people with the expertise in these areas. We just believe that this will allow for more efficient development as the maintainer will have a detailed understanding of what they're applying.

> > The arguments I've heard in favour of your proposal are summarised
> below. Apologies for paraphrasing, and for any errors, but the email thread is
> too big and too convoluted to address these all separately. I've also included
> an explanation for each item to say why we don't believe they're sufficient to
> justify your proposed change.
> >
> I thought we were doing just fine with the conversation.  The paraphrasing
> here
> is why I was upset by your top post.  You convieniently ignored all my
> supporting evidence.
> 
> > 1. Your proposal is consistent with the Linux kernel, but current state is not.
> > In both cases (current state and your proposal), the workflow is exactly the
> same as the Linux kernel. The difference we're discussing is simply the
> granularity of the repositories.
> >
> Thats simply not true.  My proposal is consistent with the linux kernel model,
> but what you want in no way is.  The graunularity is diffferent as you note,
> but
> you're adding in this requirement whereby a developer for a given PMD
> must be
> the tree maintainer for a subtree solely for the purpose of maintaining that
> PMD.  That in no way shape or form resembles the linux kernel model.  If you
> wish to do that internally to Intel, thats great, and you have all the ability
> to do that, but to mandate it as part of the community project is anathema to
> the way the linux workflow works, and open source projects in general.

We're not mandating that at all. What we're saying is that this is the approach that's in place for fm10k and i40e, and that we don't agree with your proposal to change this. For other PMDs, the model could be different.

> > DPDK is much smaller than the kernel, so the granularity is naturally going
> to be different. The kernel may combine drivers into a single repository due
> to its size and complexity, but that doesn't mean we need to do the same for
> DPDK.
> >
> Why?  You're right in the most general of senses, diffferent projects can
> work
> differently, but being different in one way (size/complexity), doesn't
> mandate
> that it be different in another way (workflow).  We can (and are) exploring
> different ways to implement workflows here, but the question is one of
> reason.
> The kernel combines drivers into a single respository because its a natural
> functional separation that allows Linus to divide the workload to
> subordinates,
> while still giving contributing developers a canonical place to go for their
> development target needs.  Its efficient (As I calculated before in the
> interleaved section below, Dave Miller integrates either from pull requests or
> individual posts, over 1000 patches on average every 2 month release cycle),
> fast (even though every patch goes to the mailing list, gets reviewed, and
> acked), and convienient for all developers.
> 
> Conversely, the I40e driver has seen 114 patches in the last 6 month period
> to
> the DPDK.  What is it about dpdk PMD's that makes a process that is as
> efficient, fast and transparent as the upstream kenrel's unacceptible to you?

I still believe the workflow and process are the same in both cases. In both cases there's a subtree to which a maintainer applies patches and then generates pull requests to the main repo. The difference in your proposal is the granularity of the subtree.

> > 2. Maintainer and SME are separate roles and should not be combined.
> > We understand that they're separate roles. For the PMDs that we're
> developing, the most efficient way for us to manage the work is to combine
> these and have one of our SMEs act as maintainer as well. That's an internal
> decision that suits the structure of our development team and the current
> state of the i40e and fm10k PMDs. Others are obviously free to make their
> own choices for PMDs that they're developing.
> >
> Thats a really interesting thing to say.  You made an internal decision,  but
> this isn't an internal project.  This is a community project.  If you want an
> internal tree to commit patches too, thats fine, you can and should do that
> for
> whatever internal workflow suits your needs, but before they get merged to
> the
> community project (which includes the I40e driver), they need to get posted
> to
> the community list to allow any and all an opportunity to review them (even
> if
> they choose not to, they deserve the opportunity). 

All of our work is posted to the mailing list and available to anybody in the community to review. That's been the case since the 1.7 release.

> It seems that, while you
> haven't said it in so many words, you are looking for ways to accelerate that
> process, and potentially cutting out the community in the process.

Absolutely not.

> Let me ask a question here: Do you intend to post all the I40e patches that
> you
> plan to commit to the I40e tree to the DPDK list?  Or do you plan to integrate
> them to the tree using only internal review, and then send a pull request to
> the
> list?  If you are planning on doing the latter, that would explain your desires
> to merge the tree maintainer and SME role, but would be a huge step
> backwards
> from all of the progress you've made toward making this project a true
> community
> project.  As Stephen indicates, what you're then doing is creating several
> out-of-tree drivers, and that would be totally unacceptable.  You're of course
> welcome to do so, but I would not accept any workflow in which changes to
> code
> did not have patches posted to the list.

As above, all of our work has been, and will continue to be, posted to the mailing list and is open to anybody in the community to review.

> > 3. A maintainer can handle a higher volume of patches than will be present
> in any individual PMD.
> > That's true, but it's also not relevant. Our goal is not to make the
> SME/maintainer for i40e, fm10k etc. a full-time position. Our goal is to have
> an expert in this position, so that we can move quickly and still ensure good
> quality software.
> >
> Please re-read your above statement. I think you're contradicting yourself
> 1) You agree that a tree maintainer can handle a higher volume of patches
> than
> any one PMD presents, implying that a tree maintainer can, when properly
> focused, efficiently take the feedback of SME's and integrate many patches
> quickly.
> 
> 2) You claim (1) is irellevant because because your goal is to put an expert in
> the position of tree maintainer so that you can move more quickly.
> 
> If you agree that (1) allows for a fast, efficient and transparent workflow,
> how
> can you both claim it is both irrelevant and that you need a merged SME/tree
> maintainer role to achieve the same goal?
> 
> Question: How exactly do you believe putting an SME in the role of tree
> maintainer will improve code quality and make code integration faster?

I think Thomas is a good example here. Theoretically, someone in his role would not need any knowledge of DPDK, since they would just be fulfilling an SCM function. However, I believe his knowledge and understanding of DPDK have been crucial in building the community and getting the project to the stage it's at now. The same applies for i40e and fm10k maintainers. We believe that having experts in these roles is the most efficient way to make progress.

> > 4. We shouldn't give maintainer work to an SME as it detracts from their
> other tasks.
> > We don't anticipate a problem with workload for the people that we have
> in these positions.
> You're having that problem right now, you just refuse to acknoweldge it.  Let
> me
> present it for you:
> http://dpdk.org/dev/patchwork/project/dpdk/list/?q=I40e
> 
> That shows the only 6 patches that have been posted for I40e since 1.8
> released,
> ranging dating back as far as November 20th.  These patches have been
> sittting
> on the list since then unacted upon.  If fact, taking a closer look, its a bit
> worse than that.  The X710 patch in that list has been integrated, but a
> version
> different from the one in patchwork.  Its probably just an oversight, but the
> fact remains, whoever is doing your subtree maintenence is focused on your
> internal needs and is ignoring their community responsibilities.  Thats a
> problem.

This is work in progress. We're confident that we'll have the necessary i40e changes in place for 2.0.

> > 5. There will be extra overhead for developers who want to implement
> changes spanning multiple PMDs.
> > That's true, but it's also something of a hypothetical argument. The people
> who've spoken against your proposal on the mailing list are from Intel and
> 6Wind, who are also the people contributing to most of these PMDs. I had a
> quick scan of the commits to see if I could spot anything from another
> contributor that might fall into this category, and I couldn't (admittedly it
> wasn't an exhaustive search, which someone else is free to do if they want).
> If this situation does arise, then Thomas has previously outlined how it can be
> handled.
> 
> Its not a hypothetical argument at all.  We have this situation upstream every
> time someone makes a patch that crosses subsystems, and its managed by
> the
> maintainers co-ordinating their efforts when merge time comes along.  Thats
> why
> its so important to find the right granularity for subtrees, so that extra
> effort is minimized.
> 
> And yes, you're right, most of the contributors currently are from 6wind and
> Intel.  The goal here is to spread that participation beyond just the two of
> you.  If you don't have a tree-maintainer that is actively handling patches on
> the list, getting things integrated in a timely fashion, no one is going to
> bother participating.
> 
> As for handling it using the workaround thomas has proposed, I've made my
> arguments to that effect already several times, but you've neglected to
> summarize them here with your top post, so let me re-iterate:
> Patch sets that cross subtrees are a challenge no matter how you slice them.
> If
> you have subtrees at a reasonable granularity, subtree maintainers can work
> together to ensure that the upstream merge goes smoothly.  If you force a
> tree
> spanning patch to be done in the parent tree you will have merge work to do
> for
> each subtree that sends you a pull request.  Having a few subtree
> maintainers
> handle that work is preferable than having to do merge fixups in the main
> tree.
> The main tree should whenever possible have clean merges.

My comment was saying that we should give weight to the views of the people who are currently doing the work in these areas. These people are strongly of the opinion that it's better to continue with the current approach.

> > In terms of where we go from here, I'd suggest the following:
> > - Thomas has already asked us about a maintainer for older Intel NICs,
> which we're looking into. We may choose to have a single repository with a
> single maintainer/SME for e1000/igb/ixgbe combined, which would limit the
> overall number of repositories.
> > - You could pursue a path of having a single repository for non-Intel NICs.
> This would obviously need to be worked with those responsible (Stephen,
> Sujith etc.).
> > - As Thomas previously suggested, we should review this in future, possibly
> after 2.0. Maybe you'll be proven right and we'll all have to apologise for
> disagreeing!
> 
> It sounds like you've already made a decision.  Thats really disheartening.
> You've gone to alot of effort to make this project more open, and I'd like to
> encourage you further in that direction.  But your comments above really
> make
> me think that you're hoping to isolate your development efforts, which is a
> step
> in the wrong direction.

What I'm doing is stating our position on your proposal, and giving my suggestions for how we move forward. There's no decision made that I'm aware of, and we're not in a position to make a decision in isolation anyway.

I suspect this is something that we will never agree on. That's fine, as we all have different opinions, and diverse opinions make for a healthy community. In this situation, our view would be that we should continue with the current approach and review again in future, as Thomas has suggested.

> Neil
> 
> 
> > > -----Original Message-----
> > > From: Neil Horman [mailto:nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org]
> > > Sent: Friday, January 16, 2015 4:51 PM
> > > To: O'driscoll, Tim
> > > Cc: Thomas Monjalon; dev-VfR2kkLFssw@public.gmane.org
> > > Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> > >
> > > On Thu, Jan 15, 2015 at 09:55:00PM +0000, O'driscoll, Tim wrote:
> > > > > -----Original Message-----
> > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> > > > > Sent: Thursday, January 15, 2015 6:51 PM
> > > > > To: Thomas Monjalon
> > > > > Cc: dev-VfR2kkLFssw@public.gmane.org
> > > > > Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> > > > >
> > > > > On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> > > > > > 2015-01-15 08:06, Neil Horman:
> > > > > > > On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon
> wrote:
> > > > > > > > 2015-01-15 04:27, Ouyang, Changchun:
> > > > > > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of
> Zhang,
> > > Helin
> > > > > > > > > > From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of
> Neil
> > > > > Horman
> > > > > > > > > > > On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen
> > > Hemminger
> > > > > wrote:
> > > > > > > > > > > > Ok, so 1.8.0 came out almost a month ago and none of
> the
> > > > > patches
> > > > > > > > > > > > that were deferred waiting for the release got merged
> since
> > > > > then.
> > > > > > > > > > > > Last commit in git is the 1.8.0 release.
> > > > > > > > > > > >
> > > > > > > > > > > > Where is the post-merge window bundle, where are the
> > > later
> > > > > commits?
> > > > > > > > > > > > Lots of patches are sitting rotting in patchwork...
> > > > > > > > > > >
> > > > > > > > > > > +1, I've had the same questions.
> > > > > > > > > > > Neil
> > > > > > > > > >
> > > > > > > > > > +1, Some patch set might be ready for being merged.
> > > > > > > > >
> > > > > > > > > +1,  the earlier some patches are merged into mainline, and
> the
> > > easier
> > > > > those
> > > > > > > > > sequent patch sets can resolve their conflicts.
> > > > > > > >
> > > > > > > > +1, there are some patches which are properly reviewed
> > > > > > > >
> > > > > > > > Reminder: sub-tree to manage specific part of DPDK can be
> open on
> > > > > request
> > > > > > >
> > > > > > > Ok, I think what you're saying here is you're too busy to handle all
> the
> > > > > patches
> > > > > > > comming in at the moment.  As such I'd like to propose a sub-tree
> > > > > encompassing
> > > > > > > all the pmds in DPDK.  I would envision that including all the acutal
> > > pmd's
> > > > > in
> > > > > > > the tree, as well as the infrastructure that is used to interface
> them to
> > > the
> > > > > > > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the
> patch
> > > pool
> > > > > > > and send you pull requests.
> > > > > >
> > > > > > The list of PMDs is increasing:
> > > > > > 	librte_pmd_af_packet
> > > > > > 	librte_pmd_bond
> > > > > > 	librte_pmd_e1000
> > > > > > 	librte_pmd_enic
> > > > > > 	librte_pmd_i40e
> > > > > > 	librte_pmd_ixgbe
> > > > > > 	librte_pmd_pcap
> > > > > > 	librte_pmd_ring
> > > > > > 	librte_pmd_virtio
> > > > > > 	librte_pmd_vmxnet3
> > > > > > 	librte_pmd_xenvirt
> > > > > > There is already some sub-trees for bnx2x, fm10k and i40e:
> > > > > > 	http://dpdk.org/browse/
> > > > > >
> > > > > Yes, and I've mentioned before that that is an absolutely silly way to
> > > break
> > > > > out
> > > > > subtrees.  You have to find a balance of workload distribution and
> > > developer
> > > > > convienience.
> > > > >
> > > > > I also note that these are problematic because you're not merging
> > > anything
> > > > > from them. Is it your intention to keep bnx2 and fm10k separate in
> > > > > perpituity?
> > > > > If so, thats a real problem, because then we effectively just have
> several
> > > out
> > > > > of tree drivers, and thats just unacceptible.
> > > > >
> > > > > > > If you could set me up with a login to dpdk.org, I'd appreciate it.
> > > > > >
> > > > > > It is preferred to have 1 sub-tree per module.
> > > > > > What do you think of managing contributions for af_packet and/or
> > > virtio?
> > > > > > It would make sense as virtio is a RedHat technology.
> > > > > > Maybe it could include vhost lib and example.
> > > > > >
> > > > > No, for reasons I've mentioned before.  If you take each pmd/library
> and
> > > > > create
> > > > > a subtree for it, you've created the most fine grained control of
> subtrees
> > > you
> > > > > could ask for, but you've created a nighmare of a burden on
> developers
> > > who
> > > > > want
> > > > > to update any code, especially if they have patches that hit multiple
> > > trees.
> > > > >
> > > > > Look at some of the stats in the dpdk tree:
> > > > >
> > > > > Library		Commits between 1.7.0 and 1.8.0
> > > > > librte_acl		5
> > > > > librte_cfgfile		0
> > > > > librte_cmdline		4
> > > > > librte_compat		0
> > > > > librte_distributor 	5
> > > > > librte_eal 		125
> > > > > librte_ether 		31
> > > > > librte_hash 		1
> > > > > librte_ip_frag 		5
> > > > > librte_ivshmem 		0
> > > > > librte_kni 		2
> > > > > librte_kvargs 		0
> > > > > librte_lpm 		1
> > > > > librte_malloc 		1
> > > > > librte_mbuf 		39
> > > > > librte_mempool 		4
> > > > > librte_meter 		0
> > > > > librte_net 		4
> > > > > librte_pipeline 	0
> > > > > librte_pmd_af_packet 	4
> > > > > librte_pmd_bond 	20
> > > > > librte_pmd_e1000 	21
> > > > > librte_pmd_enic 	12
> > > > > librte_pmd_i40e 	90
> > > > > librte_pmd_ixgbe 	83
> > > > > librte_pmd_pcap 	4
> > > > > librte_pmd_ring 	0
> > > > > librte_pmd_virtio 	21
> > > > > librte_pmd_vmxnet3 	21
> > > > > librte_pmd_xenvirt 	6
> > > > > librte_port 		6
> > > > > librte_power 		3
> > > > > librte_ring 		2
> > > > > librte_sched 		1
> > > > > librte_table 		7
> > > > > librte_timer 		0
> > > > > librte_vhost 		30
> > > > >
> > > > > If you look at all of the pmds in the dpdk tree, we're talking about
> ~300
> > > > > patches per release.  If you look at the net-next tree for the linux
> kernel,
> > > > > Dave Miller merged 569 patches on his own (based on the following
> > > > > command:
> > > > > git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/
> > > net/core/ |
> > > > > wc
> > > > > -l)
> > > > >
> > > > > And that doesn't account for the ~500 patches that come in via pull
> > > request
> > > > > from
> > > > > the wireless subtree.  Nor does it account for the merge window for
> net-
> > > > > next
> > > > > being 2 months instead of dpdk's 6 months.  Theres no need in any
> way
> > > for
> > > > > 12
> > > > > maintainers to be twiddling their thumbs waiting on ~20 patches each,
> > > and
> > > > > for
> > > > > that split, you've forced developers to potentially develop patches
> > > against 12
> > > > > trees (12 being the current number of PMD's that are in the dpdk).
> > > > >
> > > > > The right answer here is balance.  Let me split out the pmd's and
> ethernet
> > > > > infrastructure libraries to a subtree.  I'll pull in patches posted
> regarding
> > > > > pmd's and librte_ether/ip_frag etc, and send you a pull requests after
> > > each
> > > > > release so you get all the latest bits, and then pulls for stabilization on
> > > each
> > > > > -rc. I can manage 300 patches without issue, and that takes a load off
> your
> > > > > shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a
> single
> > > > > alternate tree for developers to go to for pmd and pmd infrastructure
> > > > > updates.
> > > > > Its a win-win.
> > > > >
> > > > > Regards
> > > > > Neil
> > > >
> > > > I agree with Thomas on this. The approach we've been taking for PMDs
> for
> > > newer Intel NICs is to have a separate sub-repository with a maintainer
> > > who's an expert in the area. This offloads some work from Thomas,
> ensures
> > > that the maintainer is very familiar with the PMD code and the
> corresponding
> > > hardware,
> > > As I mentioned to you in a private note, you're convoluting two roles into
> a
> > > single one here to the detriment of both:
> > >
> > > 1) A tree maintainer is a machine, who is responsible for the mechanicm
> of
> > > SCM
> > > and tree maintenence.  They are responsible for merging patches,
> making
> > > sure
> > > that merged patches make it to their upstream tree, ensuring conflicts
> get
> > > resolved, and above all, making sure that SME's review patches before
> they
> > > get
> > > merged
> > >
> > > 2) An SME (subject matter expert), is just that, someone who is
> intimately
> > > familiar with the hardware and software of a certain bit of a project.
> Their
> > > only responsibility is to ensure that proposed changes are legitimate and
> > > safe.
> > > They review patches within their purview and provide acks to the tree
> > > maintainer.
> > >
> > > When you merge these roles, you take the person most responsible for
> the
> > > stability of their code, and distract them with 1000 patch management
> > > operations, and from the work of developing new code for their area of
> > > expertise.
> > >
> > > The separation of these roles has evolved in several communities
> because of
> > > exactly the above.  Linus knows alot about the kernel, but he's never
> opened
> > > the
> > > I40e datasheet, and he doesn't have to because he trusts Dave M to
> ensure
> > > that
> > > code in his pull requests is legitimate.  Dave in turn relies on someone at
> > > Intel to ack every I40e patch on the list before he merges it.  He does
> exactly
> > > the same thing with every single other sub-component as listed in the
> > > MAINTAINERS file.  Thats how he is able to manage twice as many
> patches as
> > > the
> > > dpdk can in half the amount of time.  If its efficiency you're after, thats
> the
> > > route to go.  Please don't ignore all that evolutionary refinement.
> > >
> > >
> > > >and doesn't involve too much additional work for the developers
> involved
> > > (as you said, there isn't a huge volume of commits for any individual
> PMD).
> > > Patch volume isn't where the additional effort comes in.  Its in the
> > > determination of what tree to develop against.
> > >
> > > Lets take an example.  I'm doing work on the I40e card, so I have to look
> to
> > > see
> > > if theres a separate tree for it.  I figure out there is, so I have to clone
> > > that tree, and develop a patch against it.  So far so good.
> > >
> > > A few days later I notice a bug in the pcap pmd, so I want to write a patch
> to
> > > fix it.  If we carry your model out to the point where each pmd has its
> own
> > > subtree, I have to go find that new tree, and clone it as well (or add a new
> > > remote to my existing tree), pull those changes, branch from the proper
> > > master,
> > > and continue my work).
> > >
> > > If later I find a bug in the virtio pmd, I have to repeat the above process
> > > again, cloning a new tree, or adding a new remote for that drivers tree.
> > >
> > > It doesn't sound like alot when you're just sitting in a room talking about
> it,
> > > but for the developers actually working on the code, its a significant
> > > inconvienience, since it means that any pmd you want to touch requires
> you
> > > to go
> > > through this lookup process, ensuring your branching from the right
> master
> > > branch in the proper tree.
> > >
> > > Conversely, if you put all pmds in a single subtree, it doesn't matter what
> > > pmd a person is working on, they only have to clone the pmd subtree,
> and
> > > they're
> > > good to go.
> > >
> > >
> > > > We have this in place for i40e now, and will be applying this to fm10k,
> which
> > > hasn't been upstreamed yet but will be in time for the 2.0 release. Based
> on
> > > our experiences with those, we may well look at extending the model to
> > > include PMDs for other Intel NICs, and possibly other libraries, as well.
> > > >
> > > You really haven't.  You have an i40e tree, but you have dozens of I40e
> > > patches
> > > on the list, and all of them thus far have been integrated into the main
> tree.
> > > Ditto with the bnx2x tree and others that have been separated.  Please
> > > remember
> > > subject matter expert != repo maintainer.  The roles can be, and should
> be,
> > > separeated.
> > >
> > > > As you said, there's a balance to be struck, and too many subtrees may
> > > become unmanageable. With respect to your concern about developers
> > > having to potentially develop patches against multiple subtrees, this has
> > > never been raised as a concern by any of our development team. Is there
> > > any historical data on the number of changes that would fall into this
> > > category so we can see if it's a real problem or not?
> > > Look at the linux kernel if you want historical data on where the balance
> is.
> > > Major subsystems has become the natural breaking point for subtree
> > > maintenence.
> > > Every net driver goes through Millers net or net-next tree.  All scsi
> updates
> > > go
> > > through Bottomleys scsi tree.  FCoE changes used go through what used
> to
> > > be Rob
> > > Loves FCoE tree.  It just makes sense.  I'm sure there isn't recorded data
> to
> > > show anything more granular than that because no one ever seriously
> > > considered
> > > breaking out all 301 network drivers into their own subtree, because its
> > > obviously unmanageable at that scale. Even taken all as a single unit (as
> > > the kernel does for network drivers), a single maintainer can still handle
> the
> > > patch volume with the right subject matter experts doing timely reviews.
> > >
> > >
> > > The point of this very long message is that maintainers != repos.  Just
> > > because
> > > you're a subject matter expert in a given bit of hardware/pmd, in no way
> > > means
> > > you need to be responsible for patch merging/maintenence.  Doing so
> just
> > > makes
> > > everything harder.
> > >
> > > Neil
> >
> >

Re: Why nothing since 1.8.0?

[Neil Horman]

On Sun, Jan 18, 2015 at 09:48:33PM +0000, O'driscoll, Tim wrote:
> > -----Original Message-----
> > From: Neil Horman [mailto:nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org]
> > Sent: Sunday, January 18, 2015 6:25 PM
> > To: O'driscoll, Tim
> > Cc: Thomas Monjalon; dev-VfR2kkLFssw@public.gmane.org
> > Subject: Re: [dpdk-dev] Why nothing since 1.8.0?
> > 
> > On Sat, Jan 17, 2015 at 07:57:04PM +0000, O'driscoll, Tim wrote:
> > > I'm going to risk the wrath of the open source purists amongst you by top-
> > posting. The reason is that there has been lots of email on this subject, and I
> > want to summarise the key issue and clearly state our position on it.
> > Hoperfully nobody is offended by this!
> > >
> > Acutally, I am a bit upset by your doing this.  While top posting can be an
> > acceptible response form, doing so in an interleaved thread gives you the
> > opportunity to effectively rewrite the conversation on your own terms.
> > While
> > you might have summarized your position accurately in your mind, you've
> > discarded all the evidence that I presented in opposition.  I don't appreciate
> > that.  But we can rebuild from here, no worries.
> > 
> > > This thread has generated lots of debate, which is good, and there are a
> > number of items that I believe everybody agrees on (having a MAINTAINERS
> > file, better tools etc.). However, the key issue that we do not agree on is the
> > granularity of the repositories within DPDK.
> > >
> > No, thats not really the crux of the debate in my mind anymore, though that
> > is
> > certainly part of it, as it effects the convienience of developers to contribute
> > to the project.  More to the point, the area of disagreement here is the best,
> > most efficient way to integrate patches to various pieces of the dpdk that
> > balances developer convienience, effiency and transparency (I've not
> > ennumerated
> > that last part before, as I've not thought of the right word, and that may still
> > not be quite right, but more on it later).
> > 
> > > The current state is:
> > > - One master repository
> > > - A small number of sub-repositories, each with a separate
> > maintainer/SME, including: i40e, fm10k, bnx2x, docs, dts. These are used to
> > generate pull requests to the main repo.
> > >
> > No, this is not the current state.  The current state is:
> > - One master repository
> 
> We have a repository for docs, with a separate maintainer that was used to generate pull requests for 1.8. From our perspective that worked well.
> For i40e, 1.8 development was done in the main repository, and we agreed to transition to a separate repo for 2.0. 2.0 development is currently in progress.
> We haven't upstreamed anything for fm10k yet, but that will be done in its own repo from the start, for the 2.0 release.
> 
> > We have lots of cloned dpdk trees on dpdk.org, but there is no path from
> > them to
> > the master repository.  Nothing has been comitted to any of the subtrees,
> > despite having been open for a few months now.
> 
> The plan is to use the i40e and fm10k repos for 2.0 development, which is in progress.
> 
> >  I don't see any
> > documentation
> > indicating who the maintainer of each tree is, and so don't have the foggiest
> > idea who to contact if I want to get something merged to these trees.  They
> > aren't subtrees, they're just clones of the master repository.
> 
> A MAINTAINERS file to clarify responsibilities is a good idea.
> 
> > > You're proposing the following:
> > > - Remove the individual PMD repositories, and replace them with a single
> > repository containing all PMDs, plus parts of the core code that are closely
> > linked to the PMDs, with you as the maintainer and SMEs for each PMD.
> > >
> > Not necesarily me, mind you (though yes, I've volunteered).  I'm happy for
> > someone else to take on this role if they volunteer.  The point is not to have
> > a
> > separate repo to integrate patches for any one PMD (as theres no need, and
> > it
> > makes development harder).  I want one repository that I can use to target
> > development against all PMDs, just like we do with net/net-next in the linux
> > community.
> > 
> > > As I've said before, and as Venky has also explained in private email on this,
> > we do not agree with this proposed change. We believe it would be a
> > backward step, and would have an adverse impact on DPDK.
> > >
> > You've asserted that several times, but not once have you provided any
> > supporting evidence or data to back that assertion.  Conversely I've provided
> > several bits of evidence to support my assertion that using the linux
> > workflow
> > model would work perfectly well here and handle all our needs (which
> > include,
> > but are not limited to, yours).
> 
> The reason is to give as much control as possible to the people most familiar with the PMD code and the corresponding NIC hardware.
> 
> > > The key issue here is that we've deliberately tried to give as much control
> > as possible to those who are intimately familiar with a particular PMD and the
> > underlying hardware. In our view, that's just common sense. What you're
> > proposing is to take some of that control away, and give it to someone else
> > (in this case you) who isn't familiar with the details. We don't agree with that
> > approach.
> > >
> > Yes, you have proposed that.  The question is, why?  People intimately
> > familiar
> > with the code should be writing and reviewing code.  Why do they need the
> > responsibility for integration as well?  Thats really the question.  Answer
> > that, and perhaps we can make some process on this issue.  Tell me how one
> > of
> > the people most familiar with a given piece of hardware and the software
> > that
> > drives it having the added responsibility of handling the trivial operations of
> > SCM helps you, or anyone else?  I'll point out again here that there are 6 I40e
> > patches on the DPDK list, some as old as November 20th of last year.  4 have
> > been ACK'd, but none have been integrated, with no additional commentary
> > from
> > the experts who are tasked with the patch management role.  How is that
> > efficient, transparent or condusive to development?
> 
> We're doing a lot of work on i40e and fm10k at the moment. In both cases, somebody needs to fill the maintainer role. That could be someone familiar with the PMD code and NIC hardware, or it could be somebody without this depth of knowledge. The current situation is the first option. It's true that it doesn't have to be done that way, but it seems sensible to give as much control as possible to the people with the expertise in these areas. We just believe that this will allow for more efficient development as the maintainer will have a detailed understanding of what they're applying.
> 
> > > The arguments I've heard in favour of your proposal are summarised
> > below. Apologies for paraphrasing, and for any errors, but the email thread is
> > too big and too convoluted to address these all separately. I've also included
> > an explanation for each item to say why we don't believe they're sufficient to
> > justify your proposed change.
> > >
> > I thought we were doing just fine with the conversation.  The paraphrasing
> > here
> > is why I was upset by your top post.  You convieniently ignored all my
> > supporting evidence.
> > 
> > > 1. Your proposal is consistent with the Linux kernel, but current state is not.
> > > In both cases (current state and your proposal), the workflow is exactly the
> > same as the Linux kernel. The difference we're discussing is simply the
> > granularity of the repositories.
> > >
> > Thats simply not true.  My proposal is consistent with the linux kernel model,
> > but what you want in no way is.  The graunularity is diffferent as you note,
> > but
> > you're adding in this requirement whereby a developer for a given PMD
> > must be
> > the tree maintainer for a subtree solely for the purpose of maintaining that
> > PMD.  That in no way shape or form resembles the linux kernel model.  If you
> > wish to do that internally to Intel, thats great, and you have all the ability
> > to do that, but to mandate it as part of the community project is anathema to
> > the way the linux workflow works, and open source projects in general.
> 
> We're not mandating that at all. What we're saying is that this is the approach that's in place for fm10k and i40e, and that we don't agree with your proposal to change this. For other PMDs, the model could be different.
> 
> > > DPDK is much smaller than the kernel, so the granularity is naturally going
> > to be different. The kernel may combine drivers into a single repository due
> > to its size and complexity, but that doesn't mean we need to do the same for
> > DPDK.
> > >
> > Why?  You're right in the most general of senses, diffferent projects can
> > work
> > differently, but being different in one way (size/complexity), doesn't
> > mandate
> > that it be different in another way (workflow).  We can (and are) exploring
> > different ways to implement workflows here, but the question is one of
> > reason.
> > The kernel combines drivers into a single respository because its a natural
> > functional separation that allows Linus to divide the workload to
> > subordinates,
> > while still giving contributing developers a canonical place to go for their
> > development target needs.  Its efficient (As I calculated before in the
> > interleaved section below, Dave Miller integrates either from pull requests or
> > individual posts, over 1000 patches on average every 2 month release cycle),
> > fast (even though every patch goes to the mailing list, gets reviewed, and
> > acked), and convienient for all developers.
> > 
> > Conversely, the I40e driver has seen 114 patches in the last 6 month period
> > to
> > the DPDK.  What is it about dpdk PMD's that makes a process that is as
> > efficient, fast and transparent as the upstream kenrel's unacceptible to you?
> 
> I still believe the workflow and process are the same in both cases. In both cases there's a subtree to which a maintainer applies patches and then generates pull requests to the main repo. The difference in your proposal is the granularity of the subtree.
> 
> > > 2. Maintainer and SME are separate roles and should not be combined.
> > > We understand that they're separate roles. For the PMDs that we're
> > developing, the most efficient way for us to manage the work is to combine
> > these and have one of our SMEs act as maintainer as well. That's an internal
> > decision that suits the structure of our development team and the current
> > state of the i40e and fm10k PMDs. Others are obviously free to make their
> > own choices for PMDs that they're developing.
> > >
> > Thats a really interesting thing to say.  You made an internal decision,  but
> > this isn't an internal project.  This is a community project.  If you want an
> > internal tree to commit patches too, thats fine, you can and should do that
> > for
> > whatever internal workflow suits your needs, but before they get merged to
> > the
> > community project (which includes the I40e driver), they need to get posted
> > to
> > the community list to allow any and all an opportunity to review them (even
> > if
> > they choose not to, they deserve the opportunity). 
> 
> All of our work is posted to the mailing list and available to anybody in the community to review. That's been the case since the 1.7 release.
> 
> > It seems that, while you
> > haven't said it in so many words, you are looking for ways to accelerate that
> > process, and potentially cutting out the community in the process.
> 
> Absolutely not.
> 
> > Let me ask a question here: Do you intend to post all the I40e patches that
> > you
> > plan to commit to the I40e tree to the DPDK list?  Or do you plan to integrate
> > them to the tree using only internal review, and then send a pull request to
> > the
> > list?  If you are planning on doing the latter, that would explain your desires
> > to merge the tree maintainer and SME role, but would be a huge step
> > backwards
> > from all of the progress you've made toward making this project a true
> > community
> > project.  As Stephen indicates, what you're then doing is creating several
> > out-of-tree drivers, and that would be totally unacceptable.  You're of course
> > welcome to do so, but I would not accept any workflow in which changes to
> > code
> > did not have patches posted to the list.
> 
> As above, all of our work has been, and will continue to be, posted to the mailing list and is open to anybody in the community to review.
> 
> > > 3. A maintainer can handle a higher volume of patches than will be present
> > in any individual PMD.
> > > That's true, but it's also not relevant. Our goal is not to make the
> > SME/maintainer for i40e, fm10k etc. a full-time position. Our goal is to have
> > an expert in this position, so that we can move quickly and still ensure good
> > quality software.
> > >
> > Please re-read your above statement. I think you're contradicting yourself
> > 1) You agree that a tree maintainer can handle a higher volume of patches
> > than
> > any one PMD presents, implying that a tree maintainer can, when properly
> > focused, efficiently take the feedback of SME's and integrate many patches
> > quickly.
> > 
> > 2) You claim (1) is irellevant because because your goal is to put an expert in
> > the position of tree maintainer so that you can move more quickly.
> > 
> > If you agree that (1) allows for a fast, efficient and transparent workflow,
> > how
> > can you both claim it is both irrelevant and that you need a merged SME/tree
> > maintainer role to achieve the same goal?
> > 
> > Question: How exactly do you believe putting an SME in the role of tree
> > maintainer will improve code quality and make code integration faster?
> 
> I think Thomas is a good example here. Theoretically, someone in his role would not need any knowledge of DPDK, since they would just be fulfilling an SCM function. However, I believe his knowledge and understanding of DPDK have been crucial in building the community and getting the project to the stage it's at now. The same applies for i40e and fm10k maintainers. We believe that having experts in these roles is the most efficient way to make progress.
> 
> > > 4. We shouldn't give maintainer work to an SME as it detracts from their
> > other tasks.
> > > We don't anticipate a problem with workload for the people that we have
> > in these positions.
> > You're having that problem right now, you just refuse to acknoweldge it.  Let
> > me
> > present it for you:
> > http://dpdk.org/dev/patchwork/project/dpdk/list/?q=I40e
> > 
> > That shows the only 6 patches that have been posted for I40e since 1.8
> > released,
> > ranging dating back as far as November 20th.  These patches have been
> > sittting
> > on the list since then unacted upon.  If fact, taking a closer look, its a bit
> > worse than that.  The X710 patch in that list has been integrated, but a
> > version
> > different from the one in patchwork.  Its probably just an oversight, but the
> > fact remains, whoever is doing your subtree maintenence is focused on your
> > internal needs and is ignoring their community responsibilities.  Thats a
> > problem.
> 
> This is work in progress. We're confident that we'll have the necessary i40e changes in place for 2.0.
> 
> > > 5. There will be extra overhead for developers who want to implement
> > changes spanning multiple PMDs.
> > > That's true, but it's also something of a hypothetical argument. The people
> > who've spoken against your proposal on the mailing list are from Intel and
> > 6Wind, who are also the people contributing to most of these PMDs. I had a
> > quick scan of the commits to see if I could spot anything from another
> > contributor that might fall into this category, and I couldn't (admittedly it
> > wasn't an exhaustive search, which someone else is free to do if they want).
> > If this situation does arise, then Thomas has previously outlined how it can be
> > handled.
> > 
> > Its not a hypothetical argument at all.  We have this situation upstream every
> > time someone makes a patch that crosses subsystems, and its managed by
> > the
> > maintainers co-ordinating their efforts when merge time comes along.  Thats
> > why
> > its so important to find the right granularity for subtrees, so that extra
> > effort is minimized.
> > 
> > And yes, you're right, most of the contributors currently are from 6wind and
> > Intel.  The goal here is to spread that participation beyond just the two of
> > you.  If you don't have a tree-maintainer that is actively handling patches on
> > the list, getting things integrated in a timely fashion, no one is going to
> > bother participating.
> > 
> > As for handling it using the workaround thomas has proposed, I've made my
> > arguments to that effect already several times, but you've neglected to
> > summarize them here with your top post, so let me re-iterate:
> > Patch sets that cross subtrees are a challenge no matter how you slice them.
> > If
> > you have subtrees at a reasonable granularity, subtree maintainers can work
> > together to ensure that the upstream merge goes smoothly.  If you force a
> > tree
> > spanning patch to be done in the parent tree you will have merge work to do
> > for
> > each subtree that sends you a pull request.  Having a few subtree
> > maintainers
> > handle that work is preferable than having to do merge fixups in the main
> > tree.
> > The main tree should whenever possible have clean merges.
> 
> My comment was saying that we should give weight to the views of the people who are currently doing the work in these areas. These people are strongly of the opinion that it's better to continue with the current approach.
> 
> > > In terms of where we go from here, I'd suggest the following:
> > > - Thomas has already asked us about a maintainer for older Intel NICs,
> > which we're looking into. We may choose to have a single repository with a
> > single maintainer/SME for e1000/igb/ixgbe combined, which would limit the
> > overall number of repositories.
> > > - You could pursue a path of having a single repository for non-Intel NICs.
> > This would obviously need to be worked with those responsible (Stephen,
> > Sujith etc.).
> > > - As Thomas previously suggested, we should review this in future, possibly
> > after 2.0. Maybe you'll be proven right and we'll all have to apologise for
> > disagreeing!
> > 
> > It sounds like you've already made a decision.  Thats really disheartening.
> > You've gone to alot of effort to make this project more open, and I'd like to
> > encourage you further in that direction.  But your comments above really
> > make
> > me think that you're hoping to isolate your development efforts, which is a
> > step
> > in the wrong direction.
> 
> What I'm doing is stating our position on your proposal, and giving my suggestions for how we move forward. There's no decision made that I'm aware of, and we're not in a position to make a decision in isolation anyway.
> 
> I suspect this is something that we will never agree on. That's fine, as we all have different opinions, and diverse opinions make for a healthy community. In this situation, our view would be that we should continue with the current approach and review again in future, as Thomas has suggested.
> 
> 

I agree, we're not going to agree on this, and you've clearly already made your
decisions and gotten Thomas to agree, so I'm done wasting my time here.

Neil

Re: Why nothing since 1.8.0?

[Thomas Monjalon]

2015-01-15 13:51, Neil Horman:
> On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> > 2015-01-15 08:06, Neil Horman:
> > > Ok, I think what you're saying here is you're too busy to handle all the patches
> > > comming in at the moment.  As such I'd like to propose a sub-tree encompassing
> > > all the pmds in DPDK.  I would envision that including all the acutal pmd's in
> > > the tree, as well as the infrastructure that is used to interface them to the
> > > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
> > > and send you pull requests.
> > 
> > The list of PMDs is increasing:
> > 	librte_pmd_af_packet
> > 	librte_pmd_bond
> > 	librte_pmd_e1000
> > 	librte_pmd_enic
> > 	librte_pmd_i40e
> > 	librte_pmd_ixgbe
> > 	librte_pmd_pcap
> > 	librte_pmd_ring
> > 	librte_pmd_virtio
> > 	librte_pmd_vmxnet3
> > 	librte_pmd_xenvirt
> > There is already some sub-trees for bnx2x, fm10k and i40e:
> > 	http://dpdk.org/browse/
> > 
> Yes, and I've mentioned before that that is an absolutely silly way to break out
> subtrees.  You have to find a balance of workload distribution and developer
> convienience.

Intel requested fm10k and i40e sub-trees because there are many developments
in progress. We want to experience this model.

> I also note that these are problematic because you're not merging anything
> from them. Is it your intention to keep bnx2 and fm10k separate in perpituity?

No, I'll merge them on pull requests.
Note that they are planned for version 2.0 but not available yet.

> If so, thats a real problem, because then we effectively just have several out
> of tree drivers, and thats just unacceptible.

I don't understand what make you thinking that. They are -next tree, not out of tree.

> > > If you could set me up with a login to dpdk.org, I'd appreciate it.
> > 
> > It is preferred to have 1 sub-tree per module.
> > What do you think of managing contributions for af_packet and/or virtio?
> > It would make sense as virtio is a RedHat technology.
> > Maybe it could include vhost lib and example.
> > 
> No, for reasons I've mentioned before.  If you take each pmd/library and create
> a subtree for it, you've created the most fine grained control of subtrees you
> could ask for, but you've created a nighmare of a burden on developers who want
> to update any code, especially if they have patches that hit multiple trees.

It's not planned to have a sub-tree for each library.
And some sub-trees can be closed when activity decrease.

> Look at some of the stats in the dpdk tree:
> 
> Library		Commits between 1.7.0 and 1.8.0
> librte_acl		5
> librte_cfgfile		0
> librte_cmdline		4
> librte_compat		0
> librte_distributor 	5
> librte_eal 		125
> librte_ether 		31
> librte_hash 		1
> librte_ip_frag 		5
> librte_ivshmem 		0
> librte_kni 		2
> librte_kvargs 		0
> librte_lpm 		1
> librte_malloc 		1
> librte_mbuf 		39
> librte_mempool 		4
> librte_meter 		0
> librte_net 		4
> librte_pipeline 	0
> librte_pmd_af_packet 	4
> librte_pmd_bond 	20
> librte_pmd_e1000 	21
> librte_pmd_enic 	12
> librte_pmd_i40e 	90
> librte_pmd_ixgbe 	83
> librte_pmd_pcap 	4
> librte_pmd_ring 	0
> librte_pmd_virtio 	21
> librte_pmd_vmxnet3 	21
> librte_pmd_xenvirt 	6
> librte_port 		6
> librte_power 		3
> librte_ring 		2
> librte_sched 		1
> librte_table 		7
> librte_timer 		0
> librte_vhost 		30
> 
> If you look at all of the pmds in the dpdk tree, we're talking about ~300
> patches per release.  If you look at the net-next tree for the linux kernel,
> Dave Miller merged 569 patches on his own (based on the following command:
> git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/ net/core/ | wc
> -l)
> 
> And that doesn't account for the ~500 patches that come in via pull request from
> the wireless subtree.  Nor does it account for the merge window for net-next
> being 2 months instead of dpdk's 6 months.  Theres no need in any way for 12
> maintainers to be twiddling their thumbs waiting on ~20 patches each, and for
> that split, you've forced developers to potentially develop patches against 12
> trees (12 being the current number of PMD's that are in the dpdk).

Please stop on this wrong assumption. We keep only 1 mailing-list and use only
few sub-trees.

> The right answer here is balance.  Let me split out the pmd's and ethernet
> infrastructure libraries to a subtree.  I'll pull in patches posted regarding
> pmd's and librte_ether/ip_frag etc, and send you a pull requests after each
> release so you get all the latest bits, and then pulls for stabilization on each
> -rc. I can manage 300 patches without issue, and that takes a load off your
> shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a single
> alternate tree for developers to go to for pmd and pmd infrastructure updates.
> Its a win-win.

You misunderstood some things but I understand the global idea in your hard words.
You're right when you say balance is important and we have to experience
some solutions to find the right balance.

Note that the real challenge is not to push patches but to have them carefully
reviewed. The answer is to make sure each area of DPDK is covered by at least
one reviewer. Probably that a MAINTAINERS file could help here.

-- 
Thomas

Re: Why nothing since 1.8.0?

[Neil Horman]

On Thu, Jan 15, 2015 at 11:23:28PM +0100, Thomas Monjalon wrote:
> 2015-01-15 13:51, Neil Horman:
> > On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> > > 2015-01-15 08:06, Neil Horman:
> > > > Ok, I think what you're saying here is you're too busy to handle all the patches
> > > > comming in at the moment.  As such I'd like to propose a sub-tree encompassing
> > > > all the pmds in DPDK.  I would envision that including all the acutal pmd's in
> > > > the tree, as well as the infrastructure that is used to interface them to the
> > > > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
> > > > and send you pull requests.
> > > 
> > > The list of PMDs is increasing:
> > > 	librte_pmd_af_packet
> > > 	librte_pmd_bond
> > > 	librte_pmd_e1000
> > > 	librte_pmd_enic
> > > 	librte_pmd_i40e
> > > 	librte_pmd_ixgbe
> > > 	librte_pmd_pcap
> > > 	librte_pmd_ring
> > > 	librte_pmd_virtio
> > > 	librte_pmd_vmxnet3
> > > 	librte_pmd_xenvirt
> > > There is already some sub-trees for bnx2x, fm10k and i40e:
> > > 	http://dpdk.org/browse/
> > > 
> > Yes, and I've mentioned before that that is an absolutely silly way to break out
> > subtrees.  You have to find a balance of workload distribution and developer
> > convienience.
> 
> Intel requested fm10k and i40e sub-trees because there are many developments
> in progress. We want to experience this model.
> 
Ok, but thats not the point.  Just because a given pmd has lots of changes
doesn't mean it itself needs its own tree.  With the right separation of
responsibilities all the pmds can be managed from one tree more easily and with
less distractions to the developers doing the work for those libraries.

> > I also note that these are problematic because you're not merging anything
> > from them. Is it your intention to keep bnx2 and fm10k separate in perpituity?
> 
> No, I'll merge them on pull requests.
> Note that they are planned for version 2.0 but not available yet.
> 
Ok, good on the pull request, but I don't really see that happening.  According
to this:
http://git.dpdk.org/dev/roadmap#cycle
If we plan a 2.0 release for mid march, counting backwards, we should be at the
review period stage.  As of today in patchwork, I see 6 patches with I40e in the
title. Of those 3 have been acked, only one by someone who I think is likely a
subject matter expert on I40e.

Some of those patches have been sitting on the list since November 20th of last
year.

I think we're missing the point of a subtree.  Its created to both take some of
the load off of the upstream tree maintainer when the volume gets too high, and
it provides a location for developers to get bleeding edge code for a given
aspect of a project they might be interested in.  Neither of these things are
happening here.

> > If so, thats a real problem, because then we effectively just have several out
> > of tree drivers, and thats just unacceptible.
> 
> I don't understand what make you thinking that. They are -next tree, not out of tree.
> 
If they are the -next tree, then I apologize, because it certainly doesn't seem
that way so far.  But if they are, so be it.  That still leaves the outstanding
question though of, why one tree per pmd?  As I noted in other notes, the roles
of tree maintainer and driver maintainer (or as I would refer to it, subject
matter expert, for clairity) are separate ones.  The former is focused on the
merging of patches and general SCM process, while the latter is focused on
reviewing code within their purview.  When done properly, a single tree
maintainer can simply rely on the ACKs of the SME's to gate the merging of code,
and both parties can do their jobs much more efficiently.

> > > > If you could set me up with a login to dpdk.org, I'd appreciate it.
> > > 
> > > It is preferred to have 1 sub-tree per module.
> > > What do you think of managing contributions for af_packet and/or virtio?
> > > It would make sense as virtio is a RedHat technology.
> > > Maybe it could include vhost lib and example.
> > > 
> > No, for reasons I've mentioned before.  If you take each pmd/library and create
> > a subtree for it, you've created the most fine grained control of subtrees you
> > could ask for, but you've created a nighmare of a burden on developers who want
> > to update any code, especially if they have patches that hit multiple trees.
> 
> It's not planned to have a sub-tree for each library.
> And some sub-trees can be closed when activity decrease.
> 
But that need not happen.  If you create a single sub-tree for all the PMD's, it
will have a long life, and developers will have a long lived canonical source
from which to get the latest pmd code, and will enjoy the benefits of more
rapidly merged/reviewed code, if we follow the dual role approach that I've been
advocating.

> > Look at some of the stats in the dpdk tree:
> > 
> > Library		Commits between 1.7.0 and 1.8.0
> > librte_acl		5
> > librte_cfgfile		0
> > librte_cmdline		4
> > librte_compat		0
> > librte_distributor 	5
> > librte_eal 		125
> > librte_ether 		31
> > librte_hash 		1
> > librte_ip_frag 		5
> > librte_ivshmem 		0
> > librte_kni 		2
> > librte_kvargs 		0
> > librte_lpm 		1
> > librte_malloc 		1
> > librte_mbuf 		39
> > librte_mempool 		4
> > librte_meter 		0
> > librte_net 		4
> > librte_pipeline 	0
> > librte_pmd_af_packet 	4
> > librte_pmd_bond 	20
> > librte_pmd_e1000 	21
> > librte_pmd_enic 	12
> > librte_pmd_i40e 	90
> > librte_pmd_ixgbe 	83
> > librte_pmd_pcap 	4
> > librte_pmd_ring 	0
> > librte_pmd_virtio 	21
> > librte_pmd_vmxnet3 	21
> > librte_pmd_xenvirt 	6
> > librte_port 		6
> > librte_power 		3
> > librte_ring 		2
> > librte_sched 		1
> > librte_table 		7
> > librte_timer 		0
> > librte_vhost 		30
> > 
> > If you look at all of the pmds in the dpdk tree, we're talking about ~300
> > patches per release.  If you look at the net-next tree for the linux kernel,
> > Dave Miller merged 569 patches on his own (based on the following command:
> > git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/ net/core/ | wc
> > -l)
> > 
> > And that doesn't account for the ~500 patches that come in via pull request from
> > the wireless subtree.  Nor does it account for the merge window for net-next
> > being 2 months instead of dpdk's 6 months.  Theres no need in any way for 12
> > maintainers to be twiddling their thumbs waiting on ~20 patches each, and for
> > that split, you've forced developers to potentially develop patches against 12
> > trees (12 being the current number of PMD's that are in the dpdk).
> 
> Please stop on this wrong assumption. We keep only 1 mailing-list and use only
> few sub-trees.
I never said you needed multiple mailing lists, and you can't assert a few
sub-trees, because you don't know how many more high volume pmd's you'll have in
the future.  A single pmd-subtree with a single maintainer and multiple SME's
mitigates that problem, just like it has in the kernel.

> 
> > The right answer here is balance.  Let me split out the pmd's and ethernet
> > infrastructure libraries to a subtree.  I'll pull in patches posted regarding
> > pmd's and librte_ether/ip_frag etc, and send you a pull requests after each
> > release so you get all the latest bits, and then pulls for stabilization on each
> > -rc. I can manage 300 patches without issue, and that takes a load off your
> > shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a single
> > alternate tree for developers to go to for pmd and pmd infrastructure updates.
> > Its a win-win.
> 
> You misunderstood some things but I understand the global idea in your hard words.
> You're right when you say balance is important and we have to experience
> some solutions to find the right balance.
> 
> Note that the real challenge is not to push patches but to have them carefully
> reviewed. The answer is to make sure each area of DPDK is covered by at least
> one reviewer. Probably that a MAINTAINERS file could help here.
> 
YES!  That very thing!  We definately agree on that.  What I'm trying to point
out is that rewview/subject matter expert roles don't also have to be tree
maintainer roles.  In fact, they specficially should not be.  The trivial but
high volume work that is patch management distracts subject matter experts from
the detailed time consuming role of careful patch review.  If you split the
roles in two (like the kernel has done for years), you allows SME's to do their
job throughly and well, while allowing the tree maintainers to handle multiple
SME's and their code very efficiently.

Neil

> -- 
> Thomas
> 

Re: Why nothing since 1.8.0?

[Thomas Monjalon]

2015-01-16 12:20, Neil Horman:
> On Thu, Jan 15, 2015 at 11:23:28PM +0100, Thomas Monjalon wrote:
> > 2015-01-15 13:51, Neil Horman:
> > > On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> > > > 2015-01-15 08:06, Neil Horman:
> > > > > Ok, I think what you're saying here is you're too busy to handle all the patches
> > > > > comming in at the moment.  As such I'd like to propose a sub-tree encompassing
> > > > > all the pmds in DPDK.  I would envision that including all the acutal pmd's in
> > > > > the tree, as well as the infrastructure that is used to interface them to the
> > > > > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
> > > > > and send you pull requests.
> > > > 
> > > > The list of PMDs is increasing:
> > > > 	librte_pmd_af_packet
> > > > 	librte_pmd_bond
> > > > 	librte_pmd_e1000
> > > > 	librte_pmd_enic
> > > > 	librte_pmd_i40e
> > > > 	librte_pmd_ixgbe
> > > > 	librte_pmd_pcap
> > > > 	librte_pmd_ring
> > > > 	librte_pmd_virtio
> > > > 	librte_pmd_vmxnet3
> > > > 	librte_pmd_xenvirt
> > > > There is already some sub-trees for bnx2x, fm10k and i40e:
> > > > 	http://dpdk.org/browse/
> > > > 
> > > Yes, and I've mentioned before that that is an absolutely silly way to break out
> > > subtrees.  You have to find a balance of workload distribution and developer
> > > convienience.
> > 
> > Intel requested fm10k and i40e sub-trees because there are many developments
> > in progress. We want to experience this model.
> > 
> Ok, but thats not the point.  Just because a given pmd has lots of changes
> doesn't mean it itself needs its own tree.  With the right separation of
> responsibilities all the pmds can be managed from one tree more easily and with
> less distractions to the developers doing the work for those libraries.
> 
> > > I also note that these are problematic because you're not merging anything
> > > from them. Is it your intention to keep bnx2 and fm10k separate in perpituity?
> > 
> > No, I'll merge them on pull requests.
> > Note that they are planned for version 2.0 but not available yet.
> > 
> Ok, good on the pull request, but I don't really see that happening.  According
> to this:
> http://git.dpdk.org/dev/roadmap#cycle
> If we plan a 2.0 release for mid march, counting backwards, we should be at the
> review period stage.

?? We are January 16 today, so according to http://dpdk.org/dev/roadmap#dates,
we are not yet in review period.

> As of today in patchwork, I see 6 patches with I40e in the
> title. Of those 3 have been acked, only one by someone who I think is likely a
> subject matter expert on I40e.
> 
> Some of those patches have been sitting on the list since November 20th of last
> year.
> 
> I think we're missing the point of a subtree.  Its created to both take some of
> the load off of the upstream tree maintainer when the volume gets too high, and
> it provides a location for developers to get bleeding edge code for a given
> aspect of a project they might be interested in.  Neither of these things are
> happening here.

Please let the things happen.
If our experience shows that this subtree is not needed, it is possible to close it.
I feel it can be convenient for first releases of new drivers.

> > 
> > > If so, thats a real problem, because then we effectively just have several out
> > > of tree drivers, and thats just unacceptible.
> > 
> > I don't understand what make you thinking that. They are -next tree, not out of tree.
> > 
> If they are the -next tree, then I apologize, because it certainly doesn't seem
> that way so far.  But if they are, so be it.  That still leaves the outstanding
> question though of, why one tree per pmd?  As I noted in other notes, the roles
> of tree maintainer and driver maintainer (or as I would refer to it, subject
> matter expert, for clairity) are separate ones.  The former is focused on the
> merging of patches and general SCM process, while the latter is focused on
> reviewing code within their purview.  When done properly, a single tree
> maintainer can simply rely on the ACKs of the SME's to gate the merging of code,
> and both parties can do their jobs much more efficiently.
> 
> > > > > If you could set me up with a login to dpdk.org, I'd appreciate it.
> > > > 
> > > > It is preferred to have 1 sub-tree per module.
> > > > What do you think of managing contributions for af_packet and/or virtio?
> > > > It would make sense as virtio is a RedHat technology.
> > > > Maybe it could include vhost lib and example.
> > > > 
> > > No, for reasons I've mentioned before.  If you take each pmd/library and create
> > > a subtree for it, you've created the most fine grained control of subtrees you
> > > could ask for, but you've created a nighmare of a burden on developers who want
> > > to update any code, especially if they have patches that hit multiple trees.
> > 
> > It's not planned to have a sub-tree for each library.
> > And some sub-trees can be closed when activity decrease.
> > 
> But that need not happen.  If you create a single sub-tree for all the PMD's, it
> will have a long life, and developers will have a long lived canonical source
> from which to get the latest pmd code, and will enjoy the benefits of more
> rapidly merged/reviewed code, if we follow the dual role approach that I've been
> advocating.
> 
> > > Look at some of the stats in the dpdk tree:
> > > 
> > > Library		Commits between 1.7.0 and 1.8.0
> > > librte_acl		5
> > > librte_cfgfile		0
> > > librte_cmdline		4
> > > librte_compat		0
> > > librte_distributor 	5
> > > librte_eal 		125
> > > librte_ether 		31
> > > librte_hash 		1
> > > librte_ip_frag 		5
> > > librte_ivshmem 		0
> > > librte_kni 		2
> > > librte_kvargs 		0
> > > librte_lpm 		1
> > > librte_malloc 		1
> > > librte_mbuf 		39
> > > librte_mempool 		4
> > > librte_meter 		0
> > > librte_net 		4
> > > librte_pipeline 	0
> > > librte_pmd_af_packet 	4
> > > librte_pmd_bond 	20
> > > librte_pmd_e1000 	21
> > > librte_pmd_enic 	12
> > > librte_pmd_i40e 	90
> > > librte_pmd_ixgbe 	83
> > > librte_pmd_pcap 	4
> > > librte_pmd_ring 	0
> > > librte_pmd_virtio 	21
> > > librte_pmd_vmxnet3 	21
> > > librte_pmd_xenvirt 	6
> > > librte_port 		6
> > > librte_power 		3
> > > librte_ring 		2
> > > librte_sched 		1
> > > librte_table 		7
> > > librte_timer 		0
> > > librte_vhost 		30
> > > 
> > > If you look at all of the pmds in the dpdk tree, we're talking about ~300
> > > patches per release.  If you look at the net-next tree for the linux kernel,
> > > Dave Miller merged 569 patches on his own (based on the following command:
> > > git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/ net/core/ | wc
> > > -l)
> > > 
> > > And that doesn't account for the ~500 patches that come in via pull request from
> > > the wireless subtree.  Nor does it account for the merge window for net-next
> > > being 2 months instead of dpdk's 6 months.  Theres no need in any way for 12
> > > maintainers to be twiddling their thumbs waiting on ~20 patches each, and for
> > > that split, you've forced developers to potentially develop patches against 12
> > > trees (12 being the current number of PMD's that are in the dpdk).
> > 
> > Please stop on this wrong assumption. We keep only 1 mailing-list and use only
> > few sub-trees.
> I never said you needed multiple mailing lists, and you can't assert a few
> sub-trees, because you don't know how many more high volume pmd's you'll have in
> the future.  A single pmd-subtree with a single maintainer and multiple SME's
> mitigates that problem, just like it has in the kernel.
> 
> > 
> > > The right answer here is balance.  Let me split out the pmd's and ethernet
> > > infrastructure libraries to a subtree.  I'll pull in patches posted regarding
> > > pmd's and librte_ether/ip_frag etc, and send you a pull requests after each
> > > release so you get all the latest bits, and then pulls for stabilization on each
> > > -rc. I can manage 300 patches without issue, and that takes a load off your
> > > shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a single
> > > alternate tree for developers to go to for pmd and pmd infrastructure updates.
> > > Its a win-win.
> > 
> > You misunderstood some things but I understand the global idea in your hard words.
> > You're right when you say balance is important and we have to experience
> > some solutions to find the right balance.
> > 
> > Note that the real challenge is not to push patches but to have them carefully
> > reviewed. The answer is to make sure each area of DPDK is covered by at least
> > one reviewer. Probably that a MAINTAINERS file could help here.
> > 
> YES!  That very thing!  We definately agree on that.  What I'm trying to point
> out is that rewview/subject matter expert roles don't also have to be tree
> maintainer roles.  In fact, they specficially should not be.  The trivial but
> high volume work that is patch management distracts subject matter experts from
> the detailed time consuming role of careful patch review.  If you split the
> roles in two (like the kernel has done for years), you allows SME's to do their
> job throughly and well, while allowing the tree maintainers to handle multiple
> SME's and their code very efficiently.

So we agree on the most important thing.
I'd like to try solving the review challenge first and see what else can be
done after that. Step by step.
During that time, few sub-trees are allowed to experience it.
I suggest to continue this discussion after release 2.0. At that time, we'll
be able to give some conclusions.

-- 
Thomas

Re: Why nothing since 1.8.0?

[Matthew Hall]

On Fri, Jan 16, 2015 at 07:18:19PM +0100, Thomas Monjalon wrote:
> I'd like to try solving the review challenge first and see what else can be 
> done after that. Step by step.

FWIW, I know the kernel guys seem to really love it, but not everybody else 
has much fun trying to do the reviews reading huge patch emails. I lose a lot 
of context trying to stare at them in mutt 80x25 console etc. It would be nice 
if we could have a visual interface with syntax highlighting and comment 
capabilities, that's easier to read through quickly and clearly, like 
ReviewBoard, GitHub Pull Request UI, etc. If it had email integration to reply 
to the patch threads that'd be great too.

Also if we had some branches available where conceptually related changes are 
grouped, somebody could check out the branch with some feature they wanted to 
try, get all the related patches, integrate with their app of choice, and see 
if the app works successfully with the new feature.

Some of these things like DPDK, it isn't obvious how the feature will help or 
hurt, until you write some code against it and/or benchmark it first, because 
some of these features are kind of complicated.

Another thing... if we had some kind of wiki page, where some of the backend 
coders could mark themselves as maintainers of all the different features they 
work on, and more client-side network stack guys like me could express 
interest in certain features, we could connect the two sides so any given guy 
knows who can review his bugfix he found, or try out his new patchset to see 
if it works well in an app.

Matthew.

Re: Why nothing since 1.8.0?

[Neil Horman]

On Fri, Jan 16, 2015 at 10:58:52AM -0800, Matthew Hall wrote:
> On Fri, Jan 16, 2015 at 07:18:19PM +0100, Thomas Monjalon wrote:
> > I'd like to try solving the review challenge first and see what else can be 
> > done after that. Step by step.
> 
> FWIW, I know the kernel guys seem to really love it, but not everybody else 
> has much fun trying to do the reviews reading huge patch emails. I lose a lot 
> of context trying to stare at them in mutt 80x25 console etc.
Well, ok, then don't use mutt, no one mandates it.  You can setup
outlook/thunderbird/evolution/MTA of choice to format email properly for lkml
pretty easily.

> It would be nice 
> if we could have a visual interface with syntax highlighting and comment 
> capabilities, that's easier to read through quickly and clearly, like 
> ReviewBoard, GitHub Pull Request UI, etc. If it had email integration to reply 
> to the patch threads that'd be great too.
> 
Like Gerrit:
https://code.google.com/p/gerrit/

Its easy enough to setup your own instance and point it at your own tree for
review purposes.

> Also if we had some branches available where conceptually related changes are 
> grouped, somebody could check out the branch with some feature they wanted to 
> try, get all the related patches, integrate with their app of choice, and see 
> if the app works successfully with the new feature.
> 
That would be the master branch of a subtree, if the granularity was correct.

> Some of these things like DPDK, it isn't obvious how the feature will help or 
> hurt, until you write some code against it and/or benchmark it first, because 
> some of these features are kind of complicated.
> 
> Another thing... if we had some kind of wiki page, where some of the backend 
> coders could mark themselves as maintainers of all the different features they 
> work on, and more client-side network stack guys like me could express 
> interest in certain features, we could connect the two sides so any given guy 
> knows who can review his bugfix he found, or try out his new patchset to see 
> if it works well in an app.
> 
Thats what the MAINTAINERS file and --subject-prefix options in git-send-email
are commonly used for

Neil

Re: Why nothing since 1.8.0?

[Matthew Hall]

On Fri, Jan 16, 2015 at 03:00:57PM -0500, Neil Horman wrote:
> Like Gerrit:
> https://code.google.com/p/gerrit/

Maybe we could work on setting up a community copy? I'd prefer if we could 
avoid n=1 and make our community as strong as possible.

Matthew.

Re: Why nothing since 1.8.0?

[Neil Horman]

On Fri, Jan 16, 2015 at 12:38:48PM -0800, Matthew Hall wrote:
> On Fri, Jan 16, 2015 at 03:00:57PM -0500, Neil Horman wrote:
> > Like Gerrit:
> > https://code.google.com/p/gerrit/
> 
> Maybe we could work on setting up a community copy? I'd prefer if we could 
> avoid n=1 and make our community as strong as possible.
> 
Sure, Its a bit orthogonal to this conversation, but I think its a fine idea to
have if it aids in general reviewing.  Thomas can it be setup on dpdk.org?

Neil
> Matthew.
> 

Re: Why nothing since 1.8.0?

[Matthew Hall]

On Fri, Jan 16, 2015 at 04:14:38PM -0500, Neil Horman wrote:
> Sure, Its a bit orthogonal to this conversation, but I think its a fine idea to
> have if it aids in general reviewing.  Thomas can it be setup on dpdk.org?
> 
> Neil

Admittedly I'm not a PMD expert to comment on all the specifics of what you 
said about subtrees. But I do like to think out of the box and look at the big 
picture of what people have to say in the various threads. Your points about 
making the community strong seemed important, so I thought about the various 
subproblems to solve the whole topic:

1) some logical subtrees as you advised,

2) a clarification of who runs the subtrees and who does the -next mergeups,

3) feature branches or some other way for end users to validate new related 
functionality all together as a kind of integration testing,

4) a MAINTAINERS file, and maybe a TESTERS file, or tester / end-user entries 
in MAINTAINERS,

5) a really good friend way to review the new code like Gerrit as you advised

I think if we attack all of these we should be in good shape as the community 
continues to grow and mature.

Matthew.

Re: Why nothing since 1.8.0?

[Neil Horman]

On Fri, Jan 16, 2015 at 07:18:19PM +0100, Thomas Monjalon wrote:
> 2015-01-16 12:20, Neil Horman:
> > On Thu, Jan 15, 2015 at 11:23:28PM +0100, Thomas Monjalon wrote:
> > > 2015-01-15 13:51, Neil Horman:
> > > > On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> > > > > 2015-01-15 08:06, Neil Horman:
> > > > > > Ok, I think what you're saying here is you're too busy to handle all the patches
> > > > > > comming in at the moment.  As such I'd like to propose a sub-tree encompassing
> > > > > > all the pmds in DPDK.  I would envision that including all the acutal pmd's in
> > > > > > the tree, as well as the infrastructure that is used to interface them to the
> > > > > > core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
> > > > > > and send you pull requests.
> > > > > 
> > > > > The list of PMDs is increasing:
> > > > > 	librte_pmd_af_packet
> > > > > 	librte_pmd_bond
> > > > > 	librte_pmd_e1000
> > > > > 	librte_pmd_enic
> > > > > 	librte_pmd_i40e
> > > > > 	librte_pmd_ixgbe
> > > > > 	librte_pmd_pcap
> > > > > 	librte_pmd_ring
> > > > > 	librte_pmd_virtio
> > > > > 	librte_pmd_vmxnet3
> > > > > 	librte_pmd_xenvirt
> > > > > There is already some sub-trees for bnx2x, fm10k and i40e:
> > > > > 	http://dpdk.org/browse/
> > > > > 
> > > > Yes, and I've mentioned before that that is an absolutely silly way to break out
> > > > subtrees.  You have to find a balance of workload distribution and developer
> > > > convienience.
> > > 
> > > Intel requested fm10k and i40e sub-trees because there are many developments
> > > in progress. We want to experience this model.
> > > 
> > Ok, but thats not the point.  Just because a given pmd has lots of changes
> > doesn't mean it itself needs its own tree.  With the right separation of
> > responsibilities all the pmds can be managed from one tree more easily and with
> > less distractions to the developers doing the work for those libraries.
> > 
> > > > I also note that these are problematic because you're not merging anything
> > > > from them. Is it your intention to keep bnx2 and fm10k separate in perpituity?
> > > 
> > > No, I'll merge them on pull requests.
> > > Note that they are planned for version 2.0 but not available yet.
> > > 
> > Ok, good on the pull request, but I don't really see that happening.  According
> > to this:
> > http://git.dpdk.org/dev/roadmap#cycle
> > If we plan a 2.0 release for mid march, counting backwards, we should be at the
> > review period stage.
> 
> ?? We are January 16 today, so according to http://dpdk.org/dev/roadmap#dates,
> we are not yet in review period.
> 
Ok, you still have two weeks, but my point still stands.  At least for I40e,
several of the outstanding patches have been on the list since November of last
year, and have been Acked. If we're separating the trees out, why are we waiting
so long to merge them, shouldn't that have been done by the subtree maintainer
by now?  The merge window is called a merge window for a reason, its the time
that code gets merged.


> > As of today in patchwork, I see 6 patches with I40e in the
> > title. Of those 3 have been acked, only one by someone who I think is likely a
> > subject matter expert on I40e.
> > 
> > Some of those patches have been sitting on the list since November 20th of last
> > year.
> > 
> > I think we're missing the point of a subtree.  Its created to both take some of
> > the load off of the upstream tree maintainer when the volume gets too high, and
> > it provides a location for developers to get bleeding edge code for a given
> > aspect of a project they might be interested in.  Neither of these things are
> > happening here.
> 
> Please let the things happen.
> If our experience shows that this subtree is not needed, it is possible to close it.
> I feel it can be convenient for first releases of new drivers.
> 
I'm not disagreeing, I'm advocating for the fact that theres no need to open and
close trees as it becomes (in)convienient.  At least not at such a fine
granularity.  A single subtree for all the pmds with one tree maintainer and
several subject matter experts to do reviews has proven to be highly efficient
and flexible in many other projects (most notably the linux kernel).

> > > 
> > > > If so, thats a real problem, because then we effectively just have several out
> > > > of tree drivers, and thats just unacceptible.
> > > 
> > > I don't understand what make you thinking that. They are -next tree, not out of tree.
> > > 
> > If they are the -next tree, then I apologize, because it certainly doesn't seem
> > that way so far.  But if they are, so be it.  That still leaves the outstanding
> > question though of, why one tree per pmd?  As I noted in other notes, the roles
> > of tree maintainer and driver maintainer (or as I would refer to it, subject
> > matter expert, for clairity) are separate ones.  The former is focused on the
> > merging of patches and general SCM process, while the latter is focused on
> > reviewing code within their purview.  When done properly, a single tree
> > maintainer can simply rely on the ACKs of the SME's to gate the merging of code,
> > and both parties can do their jobs much more efficiently.
> > 
> > > > > > If you could set me up with a login to dpdk.org, I'd appreciate it.
> > > > > 
> > > > > It is preferred to have 1 sub-tree per module.
> > > > > What do you think of managing contributions for af_packet and/or virtio?
> > > > > It would make sense as virtio is a RedHat technology.
> > > > > Maybe it could include vhost lib and example.
> > > > > 
> > > > No, for reasons I've mentioned before.  If you take each pmd/library and create
> > > > a subtree for it, you've created the most fine grained control of subtrees you
> > > > could ask for, but you've created a nighmare of a burden on developers who want
> > > > to update any code, especially if they have patches that hit multiple trees.
> > > 
> > > It's not planned to have a sub-tree for each library.
> > > And some sub-trees can be closed when activity decrease.
> > > 
> > But that need not happen.  If you create a single sub-tree for all the PMD's, it
> > will have a long life, and developers will have a long lived canonical source
> > from which to get the latest pmd code, and will enjoy the benefits of more
> > rapidly merged/reviewed code, if we follow the dual role approach that I've been
> > advocating.
> > 
> > > > Look at some of the stats in the dpdk tree:
> > > > 
> > > > Library		Commits between 1.7.0 and 1.8.0
> > > > librte_acl		5
> > > > librte_cfgfile		0
> > > > librte_cmdline		4
> > > > librte_compat		0
> > > > librte_distributor 	5
> > > > librte_eal 		125
> > > > librte_ether 		31
> > > > librte_hash 		1
> > > > librte_ip_frag 		5
> > > > librte_ivshmem 		0
> > > > librte_kni 		2
> > > > librte_kvargs 		0
> > > > librte_lpm 		1
> > > > librte_malloc 		1
> > > > librte_mbuf 		39
> > > > librte_mempool 		4
> > > > librte_meter 		0
> > > > librte_net 		4
> > > > librte_pipeline 	0
> > > > librte_pmd_af_packet 	4
> > > > librte_pmd_bond 	20
> > > > librte_pmd_e1000 	21
> > > > librte_pmd_enic 	12
> > > > librte_pmd_i40e 	90
> > > > librte_pmd_ixgbe 	83
> > > > librte_pmd_pcap 	4
> > > > librte_pmd_ring 	0
> > > > librte_pmd_virtio 	21
> > > > librte_pmd_vmxnet3 	21
> > > > librte_pmd_xenvirt 	6
> > > > librte_port 		6
> > > > librte_power 		3
> > > > librte_ring 		2
> > > > librte_sched 		1
> > > > librte_table 		7
> > > > librte_timer 		0
> > > > librte_vhost 		30
> > > > 
> > > > If you look at all of the pmds in the dpdk tree, we're talking about ~300
> > > > patches per release.  If you look at the net-next tree for the linux kernel,
> > > > Dave Miller merged 569 patches on his own (based on the following command:
> > > > git log --pretty=format:%H v3.17..v3.18 -- drivers/net/ethernet/ net/core/ | wc
> > > > -l)
> > > > 
> > > > And that doesn't account for the ~500 patches that come in via pull request from
> > > > the wireless subtree.  Nor does it account for the merge window for net-next
> > > > being 2 months instead of dpdk's 6 months.  Theres no need in any way for 12
> > > > maintainers to be twiddling their thumbs waiting on ~20 patches each, and for
> > > > that split, you've forced developers to potentially develop patches against 12
> > > > trees (12 being the current number of PMD's that are in the dpdk).
> > > 
> > > Please stop on this wrong assumption. We keep only 1 mailing-list and use only
> > > few sub-trees.
> > I never said you needed multiple mailing lists, and you can't assert a few
> > sub-trees, because you don't know how many more high volume pmd's you'll have in
> > the future.  A single pmd-subtree with a single maintainer and multiple SME's
> > mitigates that problem, just like it has in the kernel.
> > 
> > > 
> > > > The right answer here is balance.  Let me split out the pmd's and ethernet
> > > > infrastructure libraries to a subtree.  I'll pull in patches posted regarding
> > > > pmd's and librte_ether/ip_frag etc, and send you a pull requests after each
> > > > release so you get all the latest bits, and then pulls for stabilization on each
> > > > -rc. I can manage 300 patches without issue, and that takes a load off your
> > > > shoulders.  I'll get fm10k integrated, as well as bnx2.  That gives us a single
> > > > alternate tree for developers to go to for pmd and pmd infrastructure updates.
> > > > Its a win-win.
> > > 
> > > You misunderstood some things but I understand the global idea in your hard words.
> > > You're right when you say balance is important and we have to experience
> > > some solutions to find the right balance.
> > > 
> > > Note that the real challenge is not to push patches but to have them carefully
> > > reviewed. The answer is to make sure each area of DPDK is covered by at least
> > > one reviewer. Probably that a MAINTAINERS file could help here.
> > > 
> > YES!  That very thing!  We definately agree on that.  What I'm trying to point
> > out is that rewview/subject matter expert roles don't also have to be tree
> > maintainer roles.  In fact, they specficially should not be.  The trivial but
> > high volume work that is patch management distracts subject matter experts from
> > the detailed time consuming role of careful patch review.  If you split the
> > roles in two (like the kernel has done for years), you allows SME's to do their
> > job throughly and well, while allowing the tree maintainers to handle multiple
> > SME's and their code very efficiently.
> 
> So we agree on the most important thing.
> I'd like to try solving the review challenge first and see what else can be
> done after that. Step by step.
ok, the review challenge is solved by identifing a maintainer for each PMD, and
recording their name in a MAINTAINERS file, then requiring that they review
patches that touch files within their purview.  I propose we create such a file
and add in the names/emails of the individuals who are responsible for those
PMD's.  I'm happy to submit a patch to that effect.  I know Stephen Hemminger
has stepped up for bnx2x, who is the responsible person for I40e?

> During that time, few sub-trees are allowed to experience it.
> I suggest to continue this discussion after release 2.0. At that time, we'll
> be able to give some conclusions.
I really don't see why you need to devise some alternate workflow here. You
have a good corollary case to guide your actions (the linux kernel workflow),
but your choosing to ignore it despite having evidence that an alternate workflow
will be beneficial.  Why not start with something that you know if functional
and efficient, and start experimenting with alterations from there?

Neil

> 
> -- 
> Thomas
> 

Re: Why nothing since 1.8.0?

[Marc Sune]

On 15/01/15 19:51, Neil Horman wrote:
> On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
>> 2015-01-15 08:06, Neil Horman:
>>> On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon wrote:
>>>> 2015-01-15 04:27, Ouyang, Changchun:
>>>>> From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang, Helin
>>>>>> From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
>>>>>>> On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger wrote:
>>>>>>>> Ok, so 1.8.0 came out almost a month ago and none of the patches
>>>>>>>> that were deferred waiting for the release got merged since then.
>>>>>>>> Last commit in git is the 1.8.0 release.
>>>>>>>>
>>>>>>>> Where is the post-merge window bundle, where are the later commits?
>>>>>>>> Lots of patches are sitting rotting in patchwork...
>>>>>>> +1, I've had the same questions.
>>>>>>> Neil
>>>>>> +1, Some patch set might be ready for being merged.
>>>>> +1,  the earlier some patches are merged into mainline, and the easier those
>>>>> sequent patch sets can resolve their conflicts.
>>>> +1, there are some patches which are properly reviewed
>>>>
>>>> Reminder: sub-tree to manage specific part of DPDK can be open on request
>>> Ok, I think what you're saying here is you're too busy to handle all the patches
>>> comming in at the moment.  As such I'd like to propose a sub-tree encompassing
>>> all the pmds in DPDK.  I would envision that including all the acutal pmd's in
>>> the tree, as well as the infrastructure that is used to interface them to the
>>> core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
>>> and send you pull requests.
>> [snip]
>> And that doesn't account for the ~500 patches that come in via pull 
>> request from the wireless subtree. Nor does it account for the merge 
>> window for net-next being 2 months instead of dpdk's 6 months.

Neil,

I don't want to hinder the discussion but: could you please point me out 
where this wireless subtree is?

Maybe I am too blind, but I cannot see it here:

http://dpdk.org/browse/

We are interested in acceleration for wireless NICs.

Marc

[snip]

Re: Why nothing since 1.8.0?

[Neil Horman]

On Fri, Jan 16, 2015 at 03:51:55PM +0100, Marc Sune wrote:
> 
> On 15/01/15 19:51, Neil Horman wrote:
> >On Thu, Jan 15, 2015 at 06:25:33PM +0100, Thomas Monjalon wrote:
> >>2015-01-15 08:06, Neil Horman:
> >>>On Thu, Jan 15, 2015 at 10:51:38AM +0100, Thomas Monjalon wrote:
> >>>>2015-01-15 04:27, Ouyang, Changchun:
> >>>>>From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Zhang, Helin
> >>>>>>From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Neil Horman
> >>>>>>>On Wed, Jan 14, 2015 at 12:23:52PM -0800, Stephen Hemminger wrote:
> >>>>>>>>Ok, so 1.8.0 came out almost a month ago and none of the patches
> >>>>>>>>that were deferred waiting for the release got merged since then.
> >>>>>>>>Last commit in git is the 1.8.0 release.
> >>>>>>>>
> >>>>>>>>Where is the post-merge window bundle, where are the later commits?
> >>>>>>>>Lots of patches are sitting rotting in patchwork...
> >>>>>>>+1, I've had the same questions.
> >>>>>>>Neil
> >>>>>>+1, Some patch set might be ready for being merged.
> >>>>>+1,  the earlier some patches are merged into mainline, and the easier those
> >>>>>sequent patch sets can resolve their conflicts.
> >>>>+1, there are some patches which are properly reviewed
> >>>>
> >>>>Reminder: sub-tree to manage specific part of DPDK can be open on request
> >>>Ok, I think what you're saying here is you're too busy to handle all the patches
> >>>comming in at the moment.  As such I'd like to propose a sub-tree encompassing
> >>>all the pmds in DPDK.  I would envision that including all the acutal pmd's in
> >>>the tree, as well as the infrastructure that is used to interface them to the
> >>>core (i.e. the ethdev/rte_ether library).  I'll gladly maintain the patch pool
> >>>and send you pull requests.
> >>[snip]
> >>And that doesn't account for the ~500 patches that come in via pull
> >>request from the wireless subtree. Nor does it account for the merge
> >>window for net-next being 2 months instead of dpdk's 6 months.
> 
> Neil,
> 
> I don't want to hinder the discussion but: could you please point me out
> where this wireless subtree is?
> 
There is none for DPDK, I'm drawing a comparison here.  The DPDK is trying to
split out subtrees at a granularity of 1 tree per pmd, which I am aruging
against because a maintainer for a pmd doesn't need their own tree to push to.

Instead I'm proposing a large granularity of where all drivers (or drivers of a
certain type) are housed in the same tree, like net-next:
https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/
or wireless:
https://git.kernel.org/cgit/linux/kernel/git/kvalo/wireless-drivers.git/

where one tree maintainer relies on the review of many subject matter experts to
validate the patches that they merge.

I'm making the comparison to argue for workflow process, nothing more.  You
won't find any wireless pmds anywhere at the moment.
Neil

> Maybe I am too blind, but I cannot see it here:
> 
> http://dpdk.org/browse/
> 
> We are interested in acceleration for wireless NICs.
> 
> Marc
> 
> [snip]
>