Re: [PATCH v4 2/2] sched/fair: update scale invariance of PELT

From: Vincent Guittot
Date: Tue Oct 23 2018 - 08:16:01 EST


On Tue, 23 Oct 2018 at 12:01, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Fri, Oct 19, 2018 at 06:17:51PM +0200, Vincent Guittot wrote:
> > In order to achieve this time scaling, a new clock_pelt is created per rq.
>
>
> > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> > index 3990818..d987f50 100644
> > --- a/kernel/sched/sched.h
> > +++ b/kernel/sched/sched.h
> > @@ -848,6 +848,8 @@ struct rq {
> > unsigned int clock_update_flags;
> > u64 clock;
> > u64 clock_task;
> > + u64 clock_pelt;
> > + unsigned long lost_idle_time;
>
> Very clever that. Seems to work out nicely. We should maybe look at

Thanks

> ensuring all these clock fields are indeed on the same cacheline.

yes good point