Re: [PATCH v5 05/10] cpufreq/schedutil: get max utilization

Juri Lelli
2018-05-29T06:32:05Z

On 28/05/18 22:08, Joel Fernandes wrote:
> On Mon, May 28, 2018 at 12:12:34PM +0200, Juri Lelli wrote:
> [..]
> > > +
> > > + util = max_t(unsigned long, util, READ_ONCE(rq->avg_dl.util_avg));
> > > +
> > > + return util;
> >
> > Anyway, just a quick thought. I guess we should experiment with this a
> > bit. Now, I don't unfortunately have a Arm platform at hand for testing.
> > Claudio, Luca (now Cc-ed), would you be able to fire some tests with
> > this change?
> >
> > Oh, adding Joel and Alessio as well that experimented with DEADLINE
> > lately.
>
> I also feel that for power reasons, dl.util_avg shouldn't drive the OPP
> beyond what the running bandwidth is, or atleast do that only if CFS tasks
> are running and being preempted as you/Vincent mentioned in one of the
> threads.

It's however a bit awkward that we might be running at a higher OPP when
CFS tasks are running (even though they are of less priority). :/

> With our DL experiments, I didn't measure power but got it to a point where
> the OPP is scaling correctly based on DL parameters. I think Alessio did
> measure power at his setup but I can't recall now. Alessio?

I see. Thanks.