Re: [Patch v4 4/6] sched/fair: update cpu_capcity to reflect thermal pressure

Peter Zijlstra
2019-10-28T15:30:18Z

On Wed, Oct 23, 2019 at 01:28:40PM +0100, Qais Yousef wrote:
> On 10/22/19 16:34, Thara Gopinath wrote:
> > cpu_capacity relflects the maximum available capacity of a cpu. Thermal
> > pressure on a cpu means this maximum available capacity is reduced. This
> > patch reduces the average thermal pressure for a cpu from its maximum
> > available capacity so that cpu_capacity reflects the actual
> > available capacity.
> >
> > Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> > ---
> > kernel/sched/fair.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index 4f9c2cb..be3e802 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -7727,6 +7727,7 @@ static unsigned long scale_rt_capacity(struct sched_domain *sd, int cpu)
> >
> > used = READ_ONCE(rq->avg_rt.util_avg);
> > used += READ_ONCE(rq->avg_dl.util_avg);
> > + used += READ_ONCE(rq->avg_thermal.load_avg);
>
> Maybe a naive question - but can we add util_avg with load_avg without
> a conversion? I thought the 2 signals have different properties.

Changelog of patch #1 explains, it's in that dense blob of text.

But yes, you're quite right that that wants a comment here.