Re: [PATCH v6 04/11] cpufreq/schedutil: use rt utilization tracking

[Vincent Guittot]

On Fri, 22 Jun 2018 at 13:41, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Fri, Jun 22, 2018 at 10:10:32AM +0200, Vincent Guittot wrote:
> > On Thu, 21 Jun 2018 at 20:57, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > >
> > > > So this (and the dl etc. equivalents) result in exactly the problems
> > > > complained about last time, no?
> > > >
> > > > What I proposed was something along the lines of:
> > > >
> > > >       util = 1024 * sg_cpu->util_cfs;
> > > >       util /= (1024 - (sg_cpu->util_rt + sg_cpu->util_dl + ...));
> > > >
> > > >       return min(sg_cpu->max, util + sg_cpu->bw_dl);
> >
> > I see that you use sg_cpu->util_dl and sg_cpu->bw_dl in your equation
> > above but this patch 04 only adds rt util_avg and the dl util_avg has
> > not been added yet.
> >  dl util_avg is added in patch 6
> > So for this patch, we are only using sg_cpu->bw_dl
>
> Yeah, not the point really.
>
> It is about how we're going to use the (rt,dl,irq etc..) util values,
> more than which particular one was introduced here.

ok

>
> I'm just not a big fan of the whole: freq := cfs_util + rt_util thing
> (as would be obvious by now).

so I'm not sure to catch what you don't like with the sum ? Is it the
special case for dl and how we switch between dl_bw and dl util_avg
which can generate a drop in frequency
Because the increase is linear regarding rt and cfs