Re: [PATCH] cpufreq: schedutil: govern how frequently we change frequency with rate_limit

From	Viresh Kumar <viresh.kumar@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] cpufreq: schedutil: govern how frequently we change frequency with rate_limit
Date	2017-02-20 11:00 +0100
Message-ID	<tcSVc-2Zx-9@gated-at.bofh.it> (permalink)
References	<tbbpl-2OF-23@gated-at.bofh.it> <tbrkm-4KJ-9@gated-at.bofh.it> <tbtvP-69S-1@gated-at.bofh.it> <tbPPI-4eh-1@gated-at.bofh.it> <tbQ93-4lj-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On 17-02-17, 13:48, Peter Zijlstra wrote:
> On Fri, Feb 17, 2017 at 01:15:56PM +0100, Rafael J. Wysocki wrote:
> > On Thursday, February 16, 2017 01:36:05 PM Peter Zijlstra wrote:
> > > On Thu, Feb 16, 2017 at 03:42:10PM +0530, Viresh Kumar wrote:
> > > > But when I discussed this with Vincent, he suggested that it may not be required
> > > > at all as the scheduler (with the helped of "decayed") doesn't call into
> > > > schedutil too often, i.e. at least 1 ms. And if the CPUs are stable enough (i.e.
> > > > no interruptions to the running task), we wouldn't reevaluate before the next
> > > > tick.
> > > 
> > > There are still the attach/detach callers to cfs_rq_util_change() that
> > > kick in for fork/exit and migration.
> > > 
> > > But yes, barring those we shouldn't end up calling it at silly rates.
> > 
> > OK
> > 
> > Does this mean that running governor computations every time its callback
> > is invoked by the scheduler would be fine?
> 
> I'd say yes right up till the point someone reports a regression ;-)

@Rafael: Do you want me to send a V2 with the changes you suggested in
commit log?

-- 
viresh

Thread

[PATCH] cpufreq: schedutil: govern how frequently we change frequency with rate_limit Viresh Kumar <viresh.kumar@linaro.org> - 2017-02-15 18:20 +0100
  Re: [PATCH] cpufreq: schedutil: govern how frequently we change frequency with rate_limit "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-02-15 23:50 +0100
    Re: [PATCH] cpufreq: schedutil: govern how frequently we change frequency with rate_limit "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-02-16 00:00 +0100
      Re: [PATCH] cpufreq: schedutil: govern how frequently we change frequency with rate_limit "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-02-16 01:10 +0100
        Re: [PATCH] cpufreq: schedutil: govern how frequently we change  frequency with rate_limit Viresh Kumar <viresh.kumar@linaro.org> - 2017-02-16 11:20 +0100
          Re: [PATCH] cpufreq: schedutil: govern how frequently we change  frequency with rate_limit Peter Zijlstra <peterz@infradead.org> - 2017-02-16 13:40 +0100
            Re: [PATCH] cpufreq: schedutil: govern how frequently we change frequency with rate_limit "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-02-17 13:30 +0100
              Re: [PATCH] cpufreq: schedutil: govern how frequently we change  frequency with rate_limit Peter Zijlstra <peterz@infradead.org> - 2017-02-17 13:50 +0100
                Re: [PATCH] cpufreq: schedutil: govern how frequently we change  frequency with rate_limit Viresh Kumar <viresh.kumar@linaro.org> - 2017-02-20 11:00 +0100
                Re: [PATCH] cpufreq: schedutil: govern how frequently we change frequency with rate_limit "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-02-20 15:00 +0100
                Re: [PATCH] cpufreq: schedutil: govern how frequently we change frequency with rate_limit "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-02-20 16:00 +0100
    Re: [PATCH] cpufreq: schedutil: govern how frequently we change  frequency with rate_limit Viresh Kumar <viresh.kumar@linaro.org> - 2017-02-16 07:30 +0100

csiph-web