[cip-dev] [RFC/RFT] -cip-rt kernels for review/testing

[cip-dev] [RFC/RFT] -cip-rt kernels for review/testing

[Pavel Machek]

Hi!

I played a bit with -rt kernels, and here are the results.

v4.19.50-rt22-cip3-rebase was reasonably easy to do, as -cip1 was
empty. v4.4.179-rt181-cip34-rebase was more interesting.

Trees are at kernel.org:

https://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-cip.git/log/?h=v4.4.179-rt181-cip34-rebase
https://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-cip.git/log/?h=v4.19.50-rt22-cip3-rebase

Basically untested. Could I ask for reviews and testing?

I know that full preemption does not work on x86-32. I sent
"PREEMPT_RT_FULL on x86-32 machine" mail to the lists

I don't know how to release useful non-rebasing trees. Is someone
using those?

Best regards,
								Pavel
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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[cip-dev] [RFC/RFT] -cip-rt kernels for review/testing

[Jan Kiszka]

On 23.06.19 22:37, Pavel Machek wrote:
> Hi!
> 
> I played a bit with -rt kernels, and here are the results.
> 

Thanks for picking this up.

> v4.19.50-rt22-cip3-rebase was reasonably easy to do, as -cip1 was
> empty. v4.4.179-rt181-cip34-rebase was more interesting.
> 
> Trees are at kernel.org:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-cip.git/log/?h=v4.4.179-rt181-cip34-rebase
> https://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-cip.git/log/?h=v4.19.50-rt22-cip3-rebase
> 
> Basically untested. Could I ask for reviews and testing?
> 
> I know that full preemption does not work on x86-32. I sent
> "PREEMPT_RT_FULL on x86-32 machine" mail to the lists
> 
> I don't know how to release useful non-rebasing trees. Is someone
> using those?

Just like the regular -cip kernel, the -rt version's primary stable feed is 
merge-based. Rebasing only comes out of the fact that a second patch series is 
involved, but I doubt many folks use that feed as source. I don't, my colleagues 
neither (AFAIK).

Please sync with Daniel Wagner on the workflow options and also on 4.4-rt 
maintenance.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

[cip-dev] [RFC/RFT] -cip-rt kernels for review/testing

[Daniel Wagner]

Hi Pavel,

On 6/24/19 8:28 AM, Jan Kiszka wrote:
> On 23.06.19 22:37, Pavel Machek wrote:
>> v4.19.50-rt22-cip3-rebase was reasonably easy to do, as -cip1 was
>> empty. v4.4.179-rt181-cip34-rebase was more interesting.

Yep, the v4.4.179 brought some conflicts. Have you compared with my 
merge for v4.4-rt? Not sure if I understand your worklfow correctly. It 
looks like you used for the rebase branches the upstream -rt patchset 
and merged the cip branch. Is this correct?

What I did for the v4.4-cip-rt and v4.19-cip-rt is following

- initial setup (only once):

took the latest cip release and applied the current/matching -rt patcheset

- regulare update:

$ cd v4.4-rt
$ git tag -l 'v4\.4\.*' --sort=v:refname | tail
$ git merge v4.4.120      [fixup conflicts]

# do some testing (this is on Linutronix -rt test infrastrucure)
$ git push lxcvs -f --follow-tag HEAD:stable-maintenance-4.4.y-rt

$ srt commit
$ srt tag

$ cd v4.4-rt-rebase
$ git rebase -i v4.4.120  [fixup conflicts]
$ srt commit
$ srt tag

# check if the -rt-rebase branch is identical to v4.4-rt
$ git diff v4.4-rt

$ srt create v4.4.115-rt130 v4.4.120-rt135
$ srt sign v4.4.115-rt130 v4.4.120-rt135
$ srt upload v4.4.115-rt130 v4.4.120-rt135
$ srt push v4.4.115-rt130 v4.4.120-rt135

# XXX push missing tags
$ git push origin v4.4.115-rt131 v4.4.116-rt132 v4.4.118-rt133 
v4.4.119-rt134

$ srt announce v4.4.115-rt130 v4.4.120-rt135 > ../announce-rt
$ cat ../announce-rt | msmtp -t --

The srt tool is available here: https://github.com/igaw/stable-rt-tools
It a few lines around git to make the steps consist. It is based on 
Steven Rostedt workflow. Tom Zanussi (also -rt stable maintainer) and I 
am using the tool to maintain the -rt trees.

>> Trees are at kernel.org:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-cip.git/log/?h=v4.4.179-rt181-cip34-rebase 
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-cip.git/log/?h=v4.19.50-rt22-cip3-rebase 
>>
>>
>> Basically untested. Could I ask for reviews and testing?

-  git fetch pavel --tags
 From git://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-cip
  ! [rejected]                  v4.4.176-cip31        -> v4.4.176-cip31 
(would clobber existing tag)
  ! [rejected]                  v4.4.176-cip31-rebase -> 
v4.4.176-cip31-rebase  (would clobber existing tag)


Was v4.4.176-cip31 rebased?

- tag pattern used to be "v4.4.[0-9]+-cip[0-9]+-rt[0-9]+", it's now
   "v4.4.[0-9]+-rt[0-9]+-cip[0-9]+".

- in the v4.4-rt is still a problem with f01f17d3705b ("mm, vmstat: make 
quiet_vmstat lighter"). It is needed to boot on x86_64 but it breaks on 
NVIDIA's boards, e.g. Jetson. Unfortunately, I don't have a NVIDIA board 
in my lab to figure out what is missing. So I suspect there is a still a 
problem hidden in the current v4.4-rt tree.

>> I know that full preemption does not work on x86-32. I sent
>> "PREEMPT_RT_FULL on x86-32 machine" mail to the lists

I haven't run the v4.4 tree in 32bit so far. I can try if I get it 
booting in my lab.

>> I don't know how to release useful non-rebasing trees. Is someone
>> using those?
> 
> Just like the regular -cip kernel, the -rt version's primary stable feed 
> is merge-based. Rebasing only comes out of the fact that a second patch 
> series is involved, but I doubt many folks use that feed as source. I 
> don't, my colleagues neither (AFAIK).

If it helps, I am going to give a talk at Plubmers on how to maintain 
the -rt trees:


"""
Maintaining out of tree patches over the long term

The PREEMPT_RT patchset is the longest existing large patchset living 
outside the Linux kernel. Over the years, the realtime developers had to 
maintain several stable kernel versions of the patchset. This talk will 
present the lessons learned from this experience, including workflow, 
tooling and release management that has proven over time to scale. The 
workflow deals with upstream changes and changes to the patchset itself. 
Now that the PREEMPT_RT patchset is about the be merged upstream, we 
want to share our toolset and methods with others who may be able to 
benefit from our experience.

This talk is for people who want to maintain an external patchset with 
stable releases.
"""

> Please sync with Daniel Wagner on the workflow options and also on 
> 4.4-rt maintenance.

Hope I could already answer a few question. In summary, have a look at 
stable-rt-tools which is the workflow implemented into a python script.

Thanks,
Daniel

[cip-dev] [RFC/RFT] -cip-rt kernels for review/testing

[Pavel Machek]

Hi!

> On 6/24/19 8:28 AM, Jan Kiszka wrote:
> >On 23.06.19 22:37, Pavel Machek wrote:
> >>v4.19.50-rt22-cip3-rebase was reasonably easy to do, as -cip1 was
> >>empty. v4.4.179-rt181-cip34-rebase was more interesting.
> 
> Yep, the v4.4.179 brought some conflicts. Have you compared with my merge
> for v4.4-rt? Not sure if I understand your worklfow correctly. It looks like
> you used for the rebase branches the upstream -rt patchset and merged the
> cip branch. Is this correct?

It looks like I'll need to redo the rebase at least for 4.4. I plan to
rebase -cip specific patches on top of -rt.

> What I did for the v4.4-cip-rt and v4.19-cip-rt is following
> 
> - initial setup (only once):
> 
> took the latest cip release and applied the current/matching -rt patcheset
> 
> - regulare update:
> 
> $ cd v4.4-rt
> $ git tag -l 'v4\.4\.*' --sort=v:refname | tail
> $ git merge v4.4.120      [fixup conflicts]
> 
> # do some testing (this is on Linutronix -rt test infrastrucure)
> $ git push lxcvs -f --follow-tag HEAD:stable-maintenance-4.4.y-rt
> 
> $ srt commit
> $ srt tag
> 
> $ cd v4.4-rt-rebase
> $ git rebase -i v4.4.120  [fixup conflicts]
> $ srt commit
> $ srt tag
> 
> # check if the -rt-rebase branch is identical to v4.4-rt
> $ git diff v4.4-rt
> 
> $ srt create v4.4.115-rt130 v4.4.120-rt135
> $ srt sign v4.4.115-rt130 v4.4.120-rt135
> $ srt upload v4.4.115-rt130 v4.4.120-rt135
> $ srt push v4.4.115-rt130 v4.4.120-rt135
> 
> # XXX push missing tags
> $ git push origin v4.4.115-rt131 v4.4.116-rt132 v4.4.118-rt133
> v4.4.119-rt134
> 
> $ srt announce v4.4.115-rt130 v4.4.120-rt135 > ../announce-rt
> $ cat ../announce-rt | msmtp -t --
> 
> The srt tool is available here: https://github.com/igaw/stable-rt-tools
> It a few lines around git to make the steps consist. It is based on Steven
> Rostedt workflow. Tom Zanussi (also -rt stable maintainer) and I am using
> the tool to maintain the -rt trees.

Thanks for pointer. It does not want to run here (incompatible version
of python 3?), so let me try to do one more manual attempt, and if
that fails I'll try to fix/workaround python problems.

> If it helps, I am going to give a talk at Plubmers on how to maintain the
> -rt trees:

Thanks for pointer. I'm not sure I'll be at Plumbers.

Best regards,
								Pavel
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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[cip-dev] [RFC/RFT] -cip-rt kernels for review/testing

[Daniel Wagner]

Hi Pavel,

>> The srt tool is available here: https://github.com/igaw/stable-rt-tools
>> It a few lines around git to make the steps consist. It is based on Steven
>> Rostedt workflow. Tom Zanussi (also -rt stable maintainer) and I am using
>> the tool to maintain the -rt trees.
> 
> Thanks for pointer. It does not want to run here (incompatible version
> of python 3?), so let me try to do one more manual attempt, and if
> that fails I'll try to fix/workaround python problems.

stable-rt-tools might depend on a newer version of Python3. I am running 
Python 3.7 here. I can't remember if there are any dependencies on newer 
version of Python3. What's the error message?

Thanks,
Daniel

[cip-dev] [RFC/RFT] -cip-rt kernels for review/testing

[SZ Lin (林上智)]

Hi Pavel,

> From: Pavel Machek <pavel@denx.de> 
> Hi!
> 
> I played a bit with -rt kernels, and here are the results.

I appreciate your effort.

> 
> v4.19.50-rt22-cip3-rebase was reasonably easy to do, as -cip1 was empty.
> v4.4.179-rt181-cip34-rebase was more interesting.
> 
> Trees are at kernel.org:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-cip.git/log/?h=v4.
> 4.179-rt181-cip34-rebase
> https://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-cip.git/log/?h=v4.
> 19.50-rt22-cip3-rebase
> 
> Basically untested. Could I ask for reviews and testing?
> 
> I know that full preemption does not work on x86-32. I sent
> "PREEMPT_RT_FULL on x86-32 machine" mail to the lists
> 
> I don't know how to release useful non-rebasing trees. Is someone using
> those?

How about adding these questions into our question list and ask Wagner afterward :-)

SZ

> 
> Best regards,
> 								Pavel
> --
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

[cip-dev] [ANNOUNCE] v4.19.50-cip3-rt1

[Pavel Machek]

Hi!

4.19.50-cip3-rt1 should be available at kernel.org. I did limited
testing, but it seems to have some bugs fixed relative to
4.19.13-cip1-rt1. (Boots on x86-32 and cyclictest on iwg20m does not
hit WARN_ON). 

Trees are available at

https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt-rebase

https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt

And their content should be identical.

Best regards,
								Pavel

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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[cip-dev] [ANNOUNCE] v4.19.50-cip3-rt1

[Jan Kiszka]

On 28.06.19 14:59, Pavel Machek wrote:
> Hi!
> 
> 4.19.50-cip3-rt1 should be available at kernel.org. I did limited
> testing, but it seems to have some bugs fixed relative to
> 4.19.13-cip1-rt1. (Boots on x86-32 and cyclictest on iwg20m does not
> hit WARN_ON).
> 
> Trees are available at
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt-rebase
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt
> 
> And their content should be identical.
> 

Shouldn't this be 4.19.50-cip3-rt2? It's the second -rt release for 4.19-cip.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

[cip-dev] [ANNOUNCE] v4.19.50-cip3-rt1

[Pavel Machek]

Hi!

> >4.19.50-cip3-rt1 should be available at kernel.org. I did limited
> >testing, but it seems to have some bugs fixed relative to
> >4.19.13-cip1-rt1. (Boots on x86-32 and cyclictest on iwg20m does not
> >hit WARN_ON).
> >
> >Trees are available at
> >
> >https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt-rebase
> >
> >https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt
> >
> >And their content should be identical.
> >
> 
> Shouldn't this be 4.19.50-cip3-rt2? It's the second -rt release for 4.19-cip.

Its first realtime release based on 4.19.50-cip3 :-). It is also based
on 4.19.50-rt22. So yes, the naming is a bit confusing.

If such version would previously be named -rt2, I'll obviously need to
fix it.

Best regards,
								Pavel
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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[cip-dev] [ANNOUNCE] v4.19.50-cip3-rt1

[Jan Kiszka]

On 04.07.19 20:20, Pavel Machek wrote:
> Hi!
> 
>>> 4.19.50-cip3-rt1 should be available at kernel.org. I did limited
>>> testing, but it seems to have some bugs fixed relative to
>>> 4.19.13-cip1-rt1. (Boots on x86-32 and cyclictest on iwg20m does not
>>> hit WARN_ON).
>>>
>>> Trees are available at
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt-rebase
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt
>>>
>>> And their content should be identical.
>>>
>>
>> Shouldn't this be 4.19.50-cip3-rt2? It's the second -rt release for 4.19-cip.
> 
> Its first realtime release based on 4.19.50-cip3 :-). It is also based
> on 4.19.50-rt22. So yes, the naming is a bit confusing.
> 
> If such version would previously be named -rt2, I'll obviously need to
> fix it.

Please keep the old naming scheme and increment the -rt number when releasing a 
new rt kernel.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

[cip-dev] [ANNOUNCE] v4.19.50-cip3-rt1

[Pavel Machek]

Hi!

> >4.19.50-cip3-rt1 should be available at kernel.org. I did limited
> >testing, but it seems to have some bugs fixed relative to
> >4.19.13-cip1-rt1. (Boots on x86-32 and cyclictest on iwg20m does not
> >hit WARN_ON).
> >
> >Trees are available at
> >
> >https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt-rebase
> >
> >https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/log/?h=linux-4.19.y-cip-rt
> >
> >And their content should be identical.
> 
> Shouldn't this be 4.19.50-cip3-rt2? It's the second -rt release for 4.19-cip.

Oh and BTW testing would be very welcome.

I tried testing it on my thinkpad X60, but it is not suitable
hardware; latency goes over 1msec quite easily. But I've seen 3msec
with iwg20m board, too. I guess I should try cyclictest on
4.19.13-cip1-rt1 so I have comparison, but that is easier said than done.

Best regards,
							Pavel

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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