Re: [PATCH v4] sched/freq: move call to cpufreq_update_util

[Vincent Guittot]

On Fri, 15 Nov 2019 at 15:06, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Fri, Nov 15, 2019 at 02:37:27PM +0100, Vincent Guittot wrote:
> > On Fri, 15 Nov 2019 at 14:25, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > >
> > > On Thu, Nov 14, 2019 at 06:07:31PM +0100, Vincent Guittot wrote:
>
> > > > +     decayed = update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);
> > > > +     decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);
> > > > +     decayed |= update_irq_load_avg(rq, 0);
> > >
> > > Should not all 3 have their windows aligned and thus alway return the
> > > exact same value?
> >
> > rt and dl yes but not irq
>
> Any reason for IRQ not to be aligned?

irq time is not accounted into task time so irq_avg use rq->clock
whereas other use rq->clock_task
But irq is also not sum up with others

>
> > But having aligned window doesn't mean that they will all decay.
> > One can have been updated just before (during a dequeue as an example)
> > or at least less than 1ms before
>
> Bah... true.