Re: [tip:sched/urgent] sched: Optimize task_sched_runtime()

From: Ingo Molnar
Date: Tue Nov 19 2013 - 02:18:15 EST



* Davidlohr Bueso <davidlohr@xxxxxx> wrote:

> On Wed, 2013-11-13 at 09:25 -0800, tip-bot for Peter Zijlstra wrote:
> > Commit-ID: 911b2898b3c9fe0048e9485ad1629ed4fce330fd
> > Gitweb: http://git.kernel.org/tip/911b2898b3c9fe0048e9485ad1629ed4fce330fd
> > Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > AuthorDate: Mon, 11 Nov 2013 18:21:56 +0100
> > Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> > CommitDate: Wed, 13 Nov 2013 13:33:54 +0100
> >
> > sched: Optimize task_sched_runtime()
> >
> > Large multi-threaded apps like to hit this using do_sys_times() and
> > then queue up on the rq->lock.
> >
> > Avoid when possible.
> >
> > Larry reported ~20% performance increase his test case.
> >
> > Reported-by: Larry Woodman <lwoodman@xxxxxxxxxx>
> > Suggested-by: Paul Turner <pjt@xxxxxxxxxx>
> > Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > Link: http://lkml.kernel.org/r/20131111172925.GG26898@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
>
> For what it's worth:
>
> Tested-by: Davidlohr Bueso <davidlohr@xxxxxx>

Thanks for the testing - the change is upstream already and unless it
causes regressions it will be part of the v3.13 kernel.

Thanks,

Ingo
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