Re: [PATCH RFC] select_idle_sibling experiments

From	Chris Mason <clm@fb.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH RFC] select_idle_sibling experiments
Date	2016-04-13 18:00 +0200
Message-ID	<rnvmV-3u7-5@gated-at.bofh.it> (permalink)
References	<rkDK3-89t-35@gated-at.bofh.it> <rkQ4y-nZ-7@gated-at.bofh.it> <rm51x-7P-9@gated-at.bofh.it> <rnem7-61z-19@gated-at.bofh.it> <rnjYt-2Gb-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Apr 13, 2016 at 05:40:20AM +0200, Mike Galbraith wrote:
> On Tue, 2016-04-12 at 22:45 +0100, Matt Fleming wrote:
> > On Sat, 09 Apr, at 01:30:34PM, Chris Mason wrote:
> > > 
> > > [ nohz throttling patch ]
> > > 
> > > I tested the nohz throttle two different ways, first with schbench's
> > > pipe simulation, it's easily 8% faster with messages bouncing between
> > > cpus.
> > > 
> > > In production it's hard to pick a single number because the benchmarks
> > > produce latency curves as the workload scales up in RPS.  The benefits
> > > range from 2-9% depending on the metric.  It's a nice win, and I'd love to
> > > see it go in.
> > 
> > Do we have any idea what the tradeoff is against power consumption for
> > throttling nohz?
> 
> That's measurable with the built in super duper watt meter gizmo
> (turbostat).  It should be dinky but existent, could be given an off
> button for particularly attentive laptop drivers to poke.  Servers
> drivers are unlikely to care given the performance win.

Our power sensors show its basically a wash during the production
benchmark runs.  Which makes sense because its really only blinking
on/off at very high frequency.

-chris

Thread

[PATCH RFC] select_idle_sibling experiments Chris Mason <clm@fb.com> - 2016-04-05 20:20 +0200
  Re: [PATCH RFC] select_idle_sibling experiments Bastien Bastien Philbert <bastienphilbert@gmail.com> - 2016-04-05 20:50 +0200
    Re: [PATCH RFC] select_idle_sibling experiments Chris Mason <clm@fb.com> - 2016-04-05 21:30 +0200
  Re: [PATCH RFC] select_idle_sibling experiments Matt Fleming <matt@codeblueprint.co.uk> - 2016-04-05 22:10 +0200
    Re: [PATCH RFC] select_idle_sibling experiments Bastien Philbert <bastienphilbert@gmail.com> - 2016-04-05 23:10 +0200
    Re: [PATCH RFC] select_idle_sibling experiments Chris Mason <clm@fb.com> - 2016-04-06 02:50 +0200
  Re: [PATCH RFC] select_idle_sibling experiments Mike Galbraith <mgalbraith@suse.de> - 2016-04-06 09:30 +0200
    Re: [PATCH RFC] select_idle_sibling experiments Chris Mason <clm@fb.com> - 2016-04-06 15:40 +0200
    Re: [PATCH RFC] select_idle_sibling experiments Chris Mason <clm@fb.com> - 2016-04-09 19:40 +0200
      Re: [PATCH RFC] select_idle_sibling experiments Matt Fleming <matt@codeblueprint.co.uk> - 2016-04-12 23:50 +0200
        Re: [PATCH RFC] select_idle_sibling experiments Mike Galbraith <mgalbraith@suse.de> - 2016-04-13 05:50 +0200
          Re: [PATCH RFC] select_idle_sibling experiments Chris Mason <clm@fb.com> - 2016-04-13 18:00 +0200
  Re: [PATCH RFC] select_idle_sibling experiments Chris Mason <clm@fb.com> - 2016-04-07 17:20 +0200
  sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-04-09 21:10 +0200
    Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-04-10 12:10 +0200
      Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-04-10 14:40 +0200
        Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-04-10 14:50 +0200
      Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-04-10 22:00 +0200
        Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-04-11 07:00 +0200
          Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-04-12 02:40 +0200
            Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-04-12 06:50 +0200
              Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-04-12 15:30 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-04-12 20:20 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-04-12 22:10 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-04-13 05:20 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-04-13 15:50 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-04-13 16:30 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-04-13 16:40 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-04-13 17:10 +0200
                Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-04-13 17:40 +0200

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