From: Greg KH <greg@kroah.com>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Linux-Stable <stable@vger.kernel.org>
Subject: Re: [PATCH 00/26] Performance-related backports for 4.12.2
Date: Tue, 25 Jul 2017 08:21:38 -0700 [thread overview]
Message-ID: <20170725152138.GA17979@kroah.com> (raw)
In-Reply-To: <20170725081435.yl6cqmvmbz2ntw6o@techsingularity.net>
On Tue, Jul 25, 2017 at 09:14:35AM +0100, Mel Gorman wrote:
> On Mon, Jul 24, 2017 at 04:29:05PM -0700, Greg KH wrote:
> > On Mon, Jul 24, 2017 at 05:44:01PM +0100, Mel Gorman wrote:
> > > On Thu, Jul 20, 2017 at 10:21:18PM +0100, Mel Gorman wrote:
> > > > This is a second round of performance-related backports based on low-hanging
> > > > fruit in the 4.13 merge window based on 4.12.2.
> > > >
> > > > As before, these have only been tested on 4.12-stable. While they may
> > > > merge against older kernels, I have no data on how it behaves and cannot
> > > > guarantee it's a good idea so I don't recommend it. There will also be
> > > > some major conflicts that are not trivial to resolve.
> > > >
> > > > For most of the tests I conducted, the impact is marginal but patches the
> > > > first two sets of patches are important for large machines and for uses
> > > > of nohz_full. The load balancing patch is fairly specific but measurable.
> > > > The removal of unnecessary IRQ disabling/enabling is borderline in terms of
> > > > performance but they are trivial patches and avoiding unnecessary expensive
> > > > operations is always a plus.
> > > >
> > >
> > > With 4.12.3, the patches 1-17 can be dropped.
> >
> > Really? Why, what happened in .3 that make the need for those 17
> > patches just "go away"?
> >
>
> One of the biggest motivation of the series was to bring in these
> commits that are now in -stable
>
> d5ba2df79bc6ae02927d5465e93eb635809e6db5 sched/topology: Fix overlapping sched_group_mask
> 3397c1f0371a49f52635c9e60e552ef3c91fa10f sched/topology: Optimize build_group_mask()
> e64918b4b7c3bac472198d7b59b6092a78092169 sched/topology: Fix building of overlapping sched-groups
>
> The series now needs to be rebased on top to deal with minor collisions
> but once it is, there is only one notable fix left related to scheduler
> topology -- "sched/topology: Fix overlapping sched_group_capacity" and it
> is borderline. The bulk of the rest are cleanups, micro-optimisations,
> simplifications and then documentation so the whole thing is
> understandable. The rebase is trivial (collisions with comments) but we
> can also live without them.
>
> > > The main commit left over
> > > that is missing from this series was "sched/topology: Fix overlapping
> > > sched_group_capacity" which is relatively minor in impact. The rest were
> > > to bring the schedulers more or less in line so debugging problems in
> > > 4.12-stable would be easier to compare with mainline and to make the 4.12
> > > scheduler easier to understand.
> > >
> > > The rest of the series should apply ok on top of 4.12.3 if you'd like to
> > > pick it up.
> >
> > So just patches 18-26?
> >
>
> Yes, that will then be the accounting fixes for nohz_full users, a load
> balancer fix when some processes are pinned to CPUs and a few minor
> optimisations that avoid unnecessary disabling of IRQs.
Ok, I've queued patches 18-26 up now, thanks!
greg k-h
prev parent reply other threads:[~2017-07-25 15:21 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-20 21:21 [PATCH 00/26] Performance-related backports for 4.12.2 Mel Gorman
2017-07-20 21:21 ` [PATCH 01/26] sched/topology: Refactor function build_overlap_sched_groups() Mel Gorman
2017-07-20 21:21 ` [PATCH 02/26] sched/topology: Fix building of overlapping sched-groups Mel Gorman
2017-07-20 21:21 ` [PATCH 03/26] sched/topology: Simplify build_overlap_sched_groups() Mel Gorman
2017-07-20 21:21 ` [PATCH 04/26] sched/debug: Print the scheduler topology group mask Mel Gorman
2017-07-20 21:21 ` [PATCH 05/26] sched/topology: Verify the first group matches the child domain Mel Gorman
2017-07-20 21:21 ` [PATCH 06/26] sched/topology: Optimize build_group_mask() Mel Gorman
2017-07-20 21:21 ` [PATCH 07/26] sched/topology: Move comment about asymmetric node setups Mel Gorman
2017-07-20 21:21 ` [PATCH 08/26] sched/topology: Remove FORCE_SD_OVERLAP Mel Gorman
2017-07-20 21:21 ` [PATCH 09/26] sched/topology: Fix overlapping sched_group_mask Mel Gorman
2017-07-20 21:21 ` [PATCH 10/26] sched/topology: Small cleanup Mel Gorman
2017-07-20 21:21 ` [PATCH 11/26] sched/topology: Add sched_group_capacity debugging Mel Gorman
2017-07-20 21:21 ` [PATCH 12/26] sched/topology: Fix overlapping sched_group_capacity Mel Gorman
2017-07-20 21:21 ` [PATCH 13/26] sched/topology: Add a few comments Mel Gorman
2017-07-20 21:21 ` [PATCH 14/26] sched/topology: Rewrite get_group() Mel Gorman
2017-07-20 21:21 ` [PATCH 15/26] sched/topology: Simplify sched_group_mask() usage Mel Gorman
2017-07-20 21:21 ` [PATCH 16/26] sched/topology: Rename sched_group_mask() Mel Gorman
2017-07-20 21:21 ` [PATCH 17/26] sched/topology: Rename sched_group_cpus() Mel Gorman
2017-07-20 21:21 ` [PATCH 18/26] vtime, sched/cputime: Remove vtime_account_user() Mel Gorman
2017-07-20 21:21 ` [PATCH 19/26] sched/cputime: Always set tsk->vtime_snap_whence after accounting vtime Mel Gorman
2017-07-20 21:21 ` [PATCH 20/26] sched/cputime: Rename vtime fields Mel Gorman
2017-07-20 21:21 ` [PATCH 21/26] sched/cputime: Move the vtime task fields to their own struct Mel Gorman
2017-07-20 21:21 ` [PATCH 22/26] sched/cputime: Accumulate vtime on top of nsec clocksource Mel Gorman
2017-07-20 21:21 ` [PATCH 23/26] sched/fair: Fix load_balance() affinity redo path Mel Gorman
2017-07-20 21:21 ` [PATCH 24/26] percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch Mel Gorman
2017-07-20 21:21 ` [PATCH 25/26] writeback: rework wb_[dec|inc]_stat family of functions Mel Gorman
2017-07-20 21:21 ` [PATCH 26/26] kernel/fork.c: virtually mapped stacks: do not disable interrupts Mel Gorman
2017-07-24 16:44 ` [PATCH 00/26] Performance-related backports for 4.12.2 Mel Gorman
2017-07-24 23:29 ` Greg KH
2017-07-25 8:14 ` Mel Gorman
2017-07-25 15:21 ` Greg KH [this message]
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