Re: [PATCH RFC] select_idle_sibling experiments

From	Mike Galbraith <mgalbraith@suse.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH RFC] select_idle_sibling experiments
Date	2016-04-13 05:50 +0200
Message-ID	<rnjYt-2Gb-1@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>
Organization	linux.* mail to news gateway

Show all headers | View raw

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.

	-Mike

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

csiph-web