Messages in this thread | | | Date | Tue, 29 May 2018 11:47:50 +0200 | From | Juri Lelli <> | Subject | Re: [PATCH v5 05/10] cpufreq/schedutil: get max utilization |
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On 29/05/18 08:48, Vincent Guittot wrote: > On 29 May 2018 at 08:31, Juri Lelli <juri.lelli@redhat.com> wrote: > > 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). :/ > > Even if cfs task has lower priority that doesn't mean that we should > not take their needs into account. > In the same way, we run at max OPP as soon as a RT task is runnable
Sure. What I fear is a little CFS utilization generating spikes because dl.util_avg became big when running DL tasks. Not sure that can happen though because such DL tasks should be throttled anyway.
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