Re: [PATCH v2 2/6] cpufreq: schedutil: reset sg_cpus's flags at IDLE enter

[Saravana Kannan]

On 07/07/2017 03:17 AM, Juri Lelli wrote:
> On 06/07/17 21:43, Joel Fernandes wrote:
> > On Tue, Jul 4, 2017 at 10:34 AM, Patrick Bellasi
> > <patrick.bellasi@xxxxxxx> wrote:
>
> [...]
>
> > > @@ -304,6 +304,12 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
> > >
> > >          sg_cpu->util = util;
> > >          sg_cpu->max = max;
> > > +
> > > +       /* CPU is entering IDLE, reset flags without triggering an update */
> > > +       if (unlikely(flags & SCHED_CPUFREQ_IDLE)) {
> > > +               sg_cpu->flags = 0;
> > > +               goto done;
> > > +       }
> >
> > Instead of defining a new flag for idle, wouldn't another way be to
> > just clear the flag from the RT scheduling class with an extra call to
> > cpufreq_update_util with flags = 0 during dequeue_rt_entity? That
> > seems to me to be also the right place to clear the flag since the
> > flag is set in the corresponding class to begin with.
>
> Make sense to me too. Also considering that for DL (with my patches) we
> don't generally want to clear the flag at dequeue time, but only when
> the 0-lag timer fires.

Makes sense to me too.

-Saravana


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