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Groups > linux.kernel > #1245438

Re: 4.3 group scheduling regression

From Peter Zijlstra <peterz@infradead.org>
Newsgroups linux.kernel
Subject Re: 4.3 group scheduling regression
Date 2015-10-13 10:10 +0200
Message-ID <qj2OL-A2-37@gated-at.bofh.it> (permalink)
References (5 earlier) <qiGXT-28r-5@gated-at.bofh.it> <qiHqW-2Xd-19@gated-at.bofh.it> <qiIdl-488-13@gated-at.bofh.it> <qiIwG-4vm-25@gated-at.bofh.it> <qiYL8-2Uy-13@gated-at.bofh.it>
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On Tue, Oct 13, 2015 at 03:55:17AM +0800, Yuyang Du wrote:

> I think maybe the real disease is the tg->load_avg is not updated in time.
> I.e., it is after migrate, the source cfs_rq does not decrease its contribution
> to the parent's tg->load_avg fast enough.

No, using the load_avg for shares calculation seems wrong; that would
mean we'd first have to ramp up the avg before you react.

You want to react quickly to actual load changes, esp. going up.

We use the avg to guess the global group load, since that's the best
compromise we have, but locally it doesn't make sense to use the avg if
we have the actual values.
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Re: CFS scheduler unfairly prefers pinned tasks Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-06 04:50 +0200
  Re: CFS scheduler unfairly prefers pinned tasks paul.szabo@sydney.edu.au - 2015-10-06 12:10 +0200
    Re: CFS scheduler unfairly prefers pinned tasks Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-06 14:20 +0200
      Re: CFS scheduler unfairly prefers pinned tasks paul.szabo@sydney.edu.au - 2015-10-06 22:50 +0200
        Re: CFS scheduler unfairly prefers pinned tasks Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-07 03:30 +0200
  Re: CFS scheduler unfairly prefers pinned tasks Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-08 10:30 +0200
    Re: CFS scheduler unfairly prefers pinned tasks paul.szabo@sydney.edu.au - 2015-10-08 13:00 +0200
      Re: CFS scheduler unfairly prefers pinned tasks Peter Zijlstra <peterz@infradead.org> - 2015-10-08 13:30 +0200
        [patch] sched: disable task group re-weighting on the desktop Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-10 15:30 +0200
          Re: [patch] sched: disable task group re-weighting on the desktop Peter Zijlstra <peterz@infradead.org> - 2015-10-10 19:10 +0200
            Re: [patch] sched: disable task group re-weighting on the desktop Peter Zijlstra <peterz@infradead.org> - 2015-10-10 19:20 +0200
            Re: [patch] sched: disable task group re-weighting on the desktop Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-11 04:30 +0200
              4.3 group scheduling regression Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-11 19:50 +0200
                Re: 4.3 group scheduling regression Peter Zijlstra <peterz@infradead.org> - 2015-10-12 09:30 +0200
                Re: 4.3 group scheduling regression Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-12 09:50 +0200
                Re: 4.3 group scheduling regression Peter Zijlstra <peterz@infradead.org> - 2015-10-12 10:10 +0200
                Re: 4.3 group scheduling regression Yuyang Du <yuyang.du@intel.com> - 2015-10-12 10:50 +0200
                Re: 4.3 group scheduling regression Peter Zijlstra <peterz@infradead.org> - 2015-10-12 11:20 +0200
                Re: 4.3 group scheduling regression Yuyang Du <yuyang.du@intel.com> - 2015-10-12 12:10 +0200
                Re: 4.3 group scheduling regression Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-12 12:30 +0200
                Re: 4.3 group scheduling regression Yuyang Du <yuyang.du@intel.com> - 2015-10-13 05:50 +0200
                Re: 4.3 group scheduling regression Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-13 06:10 +0200
                Re: 4.3 group scheduling regression Yuyang Du <yuyang.du@intel.com> - 2015-10-13 06:40 +0200
                Re: 4.3 group scheduling regression Peter Zijlstra <peterz@infradead.org> - 2015-10-13 10:10 +0200
                Re: 4.3 group scheduling regression Peter Zijlstra <peterz@infradead.org> - 2015-10-13 10:20 +0200
                Re: 4.3 group scheduling regression Yuyang Du <yuyang.du@intel.com> - 2015-10-13 10:30 +0200
                Re: 4.3 group scheduling regression Yuyang Du <yuyang.du@intel.com> - 2015-10-13 10:30 +0200
                Re: 4.3 group scheduling regression Peter Zijlstra <peterz@infradead.org> - 2015-10-12 13:50 +0200
                Re: 4.3 group scheduling regression Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-13 04:30 +0200
                Re: 4.3 group scheduling regression Yuyang Du <yuyang.du@intel.com> - 2015-10-13 05:30 +0200
                Re: 4.3 group scheduling regression Peter Zijlstra <peterz@infradead.org> - 2015-10-13 10:10 +0200
                Re: 4.3 group scheduling regression Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-12 10:50 +0200
          Re: [patch] sched: disable task group re-weighting on the desktop paul.szabo@sydney.edu.au - 2015-10-10 22:20 +0200
            Re: [patch] sched: disable task group re-weighting on the desktop Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-11 04:40 +0200
              Re: [patch] sched: disable task group re-weighting on the desktop paul.szabo@sydney.edu.au - 2015-10-11 11:30 +0200
                Re: [patch] sched: disable task group re-weighting on the desktop Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-11 15:00 +0200
          Re: [patch] sched: disable task group re-weighting on the desktop paul.szabo@sydney.edu.au - 2015-10-11 21:50 +0200
            Re: [patch] sched: disable task group re-weighting on the desktop Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-12 04:00 +0200
      Re: CFS scheduler unfairly prefers pinned tasks Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-08 16:30 +0200
        Re: CFS scheduler unfairly prefers pinned tasks paul.szabo@sydney.edu.au - 2015-10-09 00:00 +0200
          Re: CFS scheduler unfairly prefers pinned tasks Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-09 04:00 +0200
          Re: CFS scheduler unfairly prefers pinned tasks Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-10-09 04:50 +0200
            Re: CFS scheduler unfairly prefers pinned tasks paul.szabo@sydney.edu.au - 2015-10-11 11:50 +0200
    Re: CFS scheduler unfairly prefers pinned tasks Wanpeng Li <wanpeng.li@hotmail.com> - 2015-10-10 06:10 +0200
      Re: CFS scheduler unfairly prefers pinned tasks Wanpeng Li <wanpeng.li@hotmail.com> - 2015-10-10 10:00 +0200

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