Re: [RFC] sched: unused cpu in affine workload

From	Jiri Olsa <jolsa@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [RFC] sched: unused cpu in affine workload
Date	2016-04-05 11:00 +0200
Message-ID	<rkv05-sF-5@gated-at.bofh.it> (permalink)
References	(2 earlier) <rk8ZA-Wy-23@gated-at.bofh.it> <rk99g-118-21@gated-at.bofh.it> <rkcJP-3AF-3@gated-at.bofh.it> <rkiFA-89A-5@gated-at.bofh.it> <rkko3-VB-23@gated-at.bofh.it>
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On Mon, Apr 04, 2016 at 11:34:50PM +0200, Peter Zijlstra wrote:
> On Mon, Apr 04, 2016 at 03:45:16PM -0400, Rik van Riel wrote:
> > An optimal solution is NP hard.
> > 
> > Heuristics that "move tasks with pressure" may be
> > much more doable, and lead to perfectly satisfactory
> > results, especially if most migrations happen within
> > a socket (and the same shared L3 cache).
> 
> Right; trick will be finding something that mostly works without making
> the regular balance paths increase in complexity.
> 
> As per the argument in kernel/sched/fair.c:5694 the current
> load-balancing averages out to O(n), and I would very much like to keep
> it that way.

guys, thanks a lot for all the thoughts and suggestions,
I'll try to come up with something

jirka

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[RFC] sched: unused cpu in affine workload Jiri Olsa <jolsa@redhat.com> - 2016-04-04 10:30 +0200
  Re: [RFC] sched: unused cpu in affine workload Peter Zijlstra <peterz@infradead.org> - 2016-04-04 10:50 +0200
  Re: [RFC] sched: unused cpu in affine workload Ingo Molnar <mingo@kernel.org> - 2016-04-04 11:00 +0200
    Re: [RFC] sched: unused cpu in affine workload Ingo Molnar <mingo@kernel.org> - 2016-04-04 11:30 +0200
      Re: [RFC] sched: unused cpu in affine workload Ingo Molnar <mingo@kernel.org> - 2016-04-04 11:40 +0200
        Re: [RFC] sched: unused cpu in affine workload Peter Zijlstra <peterz@infradead.org> - 2016-04-04 15:30 +0200
          Re: [RFC] sched: unused cpu in affine workload Rik van Riel <riel@redhat.com> - 2016-04-04 21:50 +0200
            Re: [RFC] sched: unused cpu in affine workload Peter Zijlstra <peterz@infradead.org> - 2016-04-04 23:40 +0200
              Re: [RFC] sched: unused cpu in affine workload Jiri Olsa <jolsa@redhat.com> - 2016-04-05 11:00 +0200

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