Messages in this thread | | | From | Vincent Guittot <> | Date | Fri, 8 Jun 2018 15:38:46 +0200 | Subject | Re: [PATCH v6 06/11] cpufreq/schedutil: use dl utilization tracking |
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On 8 June 2018 at 15:36, Juri Lelli <juri.lelli@redhat.com> wrote: > On 08/06/18 14:54, Juri Lelli wrote: >> On 08/06/18 14:48, Vincent Guittot wrote: >> > On 8 June 2018 at 14:39, Juri Lelli <juri.lelli@redhat.com> wrote: >> > > Hi Vincent, >> > > >> > > On 08/06/18 14:09, Vincent Guittot wrote: >> > >> Now that we have both the dl class bandwidth requirement and the dl class >> > >> utilization, we can detect when CPU is fully used so we should run at max. >> > >> Otherwise, we keep using the dl bandwidth requirement to define the >> > >> utilization of the CPU >> > >> >> > >> Cc: Ingo Molnar <mingo@redhat.com> >> > >> Cc: Peter Zijlstra <peterz@infradead.org> >> > >> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> >> > >> --- >> > > >> > > [...] >> > > >> > >> @@ -190,20 +192,24 @@ static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu) >> > >> if (rq->rt.rt_nr_running) >> > >> return sg_cpu->max; >> > >> >> > >> - util = sg_cpu->util_dl; >> > >> - util += sg_cpu->util_cfs; >> > >> + util = sg_cpu->util_cfs; >> > >> util += sg_cpu->util_rt; >> > >> >> > >> + if ((util + sg_cpu->util_dl) >= sg_cpu->max) >> > >> + return sg_cpu->max; >> > >> + >> > > >> > > Mmm, won't we run at max (or reach max) with a, say, 100ms/500ms DL task >> > > running alone? >> > >> > not for a 100ms running task. You have to run more than 320ms to reach max value >> > >> > 100ms/500ms will vary between 0 and 907 >> >> OK, right, my point I guess is still that such a task will run fine at >> ~250 and it might be save more energy by doing so? > > As discussed on IRC, we still endup selecting 1/5 of max freq because > util_dl is below max. > > So, turning point is at ~320ms/[something_bigger], which looks a pretty > big runtime, but I'm not sure if having that is OK. Also, it becomes > smaller with CFS/RT background "perturbations". Mmm. > > BTW, adding Luca and Claudio. :)
Argh... I have added few more but forgot Luca and Claudio. I'm very sorry
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