Re: sched: tweak select_idle_sibling to look for idle threads

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	Re: sched: tweak select_idle_sibling to look for idle threads
Date	2016-05-02 17:20 +0200
Message-ID	<runND-5Nz-3@gated-at.bofh.it> (permalink)
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On Mon, May 02, 2016 at 04:50:04PM +0200, Mike Galbraith wrote:

> Order is one thing, but what the old behavior does first and foremost
> is when the box starts getting really busy, only looking at target's
> sibling shuts select_idle_sibling() down instead of letting it wreck
> things.  Once cores are moving, there are no large piles of anything
> left to collect other than pain.

> Anyway, the has_idle_cores business seems to shut select_idle_sibling()
> down rather nicely when the the box gets busy.  Forcing either core,
> target's sibling or go fish turned in a top end win on 48 rq/socket.

FWIW making the select_idle_core() thing iterate in the old style (start
at target and wrap around) did bring an improvement, even in the face of
has_idle_cores; it shrank the hole between OLD_IDLE and
IDLE_CORES+IDLE_SMT (my variant of your #if 1 thing), but did not
completely eliminate it (for sysbench-psql-oltp).

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Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-04-30 14:50 +0200
  Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-01 09:20 +0200
    Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-01 11:00 +0200
      Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-01 11:30 +0200
        Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-07 11:10 +0200
          Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-08 10:10 +0200
            Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-09 04:40 +0200
              Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 05:50 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-09 06:10 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 09:50 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-09 11:00 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 11:40 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-10 09:10 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-10 09:50 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-05-10 17:30 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-11 05:00 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-05-11 06:20 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-11 11:10 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-05-11 12:00 +0200
              Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 06:00 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-09 06:20 +0200
    Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-02 10:50 +0200
      Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-02 17:00 +0200
        Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-02 17:00 +0200
          Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-02 17:50 +0200
            Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-03 16:40 +0200
              Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-03 17:20 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-04 12:40 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-04 17:40 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Matt Fleming <matt@codeblueprint.co.uk> - 2016-05-06 00:10 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-06 21:00 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-09 10:40 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 11:00 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-04 17:50 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-04 19:50 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-05 11:40 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-05 16:00 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-06 09:20 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-06 19:30 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-06 09:30 +0200
          Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-02 19:40 +0200
        Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-02 17:10 +0200
          Re: sched: tweak select_idle_sibling to look for idle threads Ingo Molnar <mingo@kernel.org> - 2016-05-02 18:10 +0200
            Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-03 13:40 +0200
              Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-03 20:30 +0200
        Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-02 17:20 +0200

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