Re: [RFC PATCH 0/7] Introduce thermal pressure

From: Juri Lelli
Date: Wed Oct 10 2018 - 08:50:43 EST


On 10/10/18 14:34, Vincent Guittot wrote:
> Hi Juri,
>
> On Wed, 10 Oct 2018 at 14:23, Juri Lelli <juri.lelli@xxxxxxxxx> wrote:
> >
> > On 10/10/18 14:04, Vincent Guittot wrote:
> >
> > [...]
> >
> > > The problem was the same with RT, the cfs utilization was lower than
> > > reality because RT steals soem cycle to CFS
> > > So schedutil was selecting a lower frequency when cfs was running
> > > whereas the CPU was fully used.
> > > The same can happen with thermal:
> > > cap the max freq because of thermal
> > > the utilization with decrease.
> > > remove the cap
> > > the utilization is still low and you will select a low OPP because you
> > > don't take into account cycle stolen by thermal like with RT
> >
> > What if we scale frequency component considering the capped temporary
> > max?
>
> Do you mean using a kind of scale_thermal_capacity in accumulate_sum
> when computing utilization ?

Yeah, something like that I guess. So that we account for temporary
"fake" 1024..