Messages in this thread | | | From | Vincent Guittot <> | Date | Wed, 16 May 2018 09:13:20 +0200 | Subject | Re: [PATCH 3/3] sched/fair: schedutil: explicit update only when required |
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On 15 May 2018 at 18:53, Peter Zijlstra <peterz@infradead.org> wrote: > On Tue, May 15, 2018 at 03:53:43PM +0100, Patrick Bellasi wrote: >> On 15-May 12:19, Vincent Guittot wrote: >> > On 14 May 2018 at 18:32, Patrick Bellasi <patrick.bellasi@arm.com> wrote: > >> > Yes se becomes NULL only when you reach root domain > > root group; domains are something else again ;-)
yes good point :-)
> >> Thus, the scheduler knows that we are going to sleep: does is really >> makes sense to send a notification in this case? > > It might; esp. on these very slow changing machines. > >> What about adding a new explicit callback at the end of: >> update_blocked_averages() ? >> >> Something like: >> >> ---8<--- >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index cb77407ba485..6eb0f31c656d 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -7740,6 +7740,9 @@ static void update_blocked_averages(int cpu) >> if (done) >> rq->has_blocked_load = 0; >> #endif >> + >> + cpufreq_update_util(rq, SCHED_CPUFREQ_IDLE); >> + >> rq_unlock_irqrestore(rq, &rf); >> } >> ---8<--- >> >> Where we can also pass in a new SCHED_CPUFREQ_IDLE flag just to notify >> schedutil that the CPU is currently IDLE? >> >> Could that work? > > Simlarly you could add ENQUEUE/DEQUEUE flags I suppose. But let's do all > that later in separate patches and evaluate the impact separately, OK?
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