Re: [PATCH 2/5] cpufreq: schedutil: support scheduler cpufreq callbacks on remote CPUs

From	Steve Muckle <steve.muckle@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/5] cpufreq: schedutil: support scheduler cpufreq callbacks on remote CPUs
Date	2016-05-20 01:00 +0200
Message-ID	<rAF57-5TT-3@gated-at.bofh.it> (permalink)
References	<rx0Uz-5md-5@gated-at.bofh.it> <rx0Uz-5md-13@gated-at.bofh.it> <rAj4C-eI-15@gated-at.bofh.it> <rABbb-3rE-1@gated-at.bofh.it> <rADd5-4JM-9@gated-at.bofh.it>
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On Thu, May 19, 2016 at 10:55:23PM +0200, Rafael J. Wysocki wrote:
> >> > +static inline bool sugov_queue_remote_callback(struct sugov_policy *sg_policy,
> >> > +                                        int cpu)
> >> > +{
> >> > +       struct cpufreq_policy *policy = sg_policy->policy;
> >> > +
> >> > +       if (!cpumask_test_cpu(smp_processor_id(), policy->cpus)) {
> >>
> >> This check is overkill for policies that aren't shared (and we have a
> >> special case for them already).
> >
> > I don't see why it is overkill -
> 
> Because it requires more computation, memory accesses etc than simply
> comparing smp_processor_id() with cpu.

Do you have a preference on how to restructure this? Otherwise I'll
create a second version of sugov_update_commit, factoring out as much of
it as I can into two inline sub-functions. 

...
> 
> > but it seems like an odd inconsistency for the governor to trace unchanged
> > frequencies when fast switches are enabled but not otherwise. It'd be
> > useful I think for profiling and tuning if the tracing was consistent.
> 
> Well, fair enough.
> 
> > This behavioral change is admittedly not part of the purpose of the
> > patch and could be split out if needbe.
> 
> No need to split IMO, but it might be prudent to mention that change
> in behavior in the changelog.

Will do.

thanks,
Steve

Thread

Re: [PATCH 2/5] cpufreq: schedutil: support scheduler cpufreq  callbacks on remote CPUs "Rafael J. Wysocki" <rafael@kernel.org> - 2016-05-19 01:30 +0200
  Re: [PATCH 2/5] cpufreq: schedutil: support scheduler cpufreq  callbacks on remote CPUs Steve Muckle <steve.muckle@linaro.org> - 2016-05-19 20:50 +0200
    Re: [PATCH 2/5] cpufreq: schedutil: support scheduler cpufreq  callbacks on remote CPUs "Rafael J. Wysocki" <rafael@kernel.org> - 2016-05-19 23:00 +0200
      Re: [PATCH 2/5] cpufreq: schedutil: support scheduler cpufreq  callbacks on remote CPUs Steve Muckle <steve.muckle@linaro.org> - 2016-05-20 01:00 +0200
        Re: [PATCH 2/5] cpufreq: schedutil: support scheduler cpufreq  callbacks on remote CPUs "Rafael J. Wysocki" <rafael@kernel.org> - 2016-05-20 01:20 +0200

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