Messages in this thread | | | Date | Wed, 13 Nov 2019 19:09:32 +0100 | From | Vincent Guittot <> | Subject | Re: [PATCH v2] sched/freq: move call to cpufreq_update_util |
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Le Wednesday 13 Nov 2019 à 18:50:35 (+0100), Vincent Guittot a écrit : > Le Wednesday 13 Nov 2019 à 15:09:47 (+0100), Dietmar Eggemann a écrit : > > On 13.11.19 14:30, Vincent Guittot wrote: > > > On Wed, 13 Nov 2019 at 11:50, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote: > > >> > > >> On 12.11.19 16:05, Vincent Guittot wrote: > > >>> Le Tuesday 12 Nov 2019 à 15:48:13 (+0100), Vincent Guittot a écrit : > > > > [...] > > > > >>>> @@ -7493,9 +7495,9 @@ static void update_blocked_averages(int cpu) > > >>>> * that RT, DL and IRQ signals have been updated before updating CFS. > > >>>> */ > > >>>> curr_class = rq->curr->sched_class; > > >>>> - update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); > > >>>> - update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); > > >>>> - update_irq_load_avg(rq, 0); > > >>>> + decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); > > >>>> + decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); > > >>>> + decayed |= update_irq_load_avg(rq, 0); > > >> > > >> Why not 'decayed = update_cfs_rq_load_avg()' like in the > > >> !CONFIG_FAIR_GROUP_SCHED case? > > > > > > Because it is handled by the update_load_avg() in > > > for_each_leaf_cfs_rq_safe() loop > > > > > > This means that we can have 2 calls to cpufreq_update_util in > > > update_blocked_average() but at least the values will be up to date in > > > both calls unlike previously. > > > > > > I'm going to prepare an additional patch to remove this useless call. > > > I have also seen some possible further optimization that i need to > > > study a bit more before preparing a patch > > > > I see. The update_load_avg() call for the taskgroup skeleton se > > (cfs_rq->tg->se[cpu]). But what happens to the cpu which only has the > > root cfs_rq i the list? It doesn't have a skeleton se. > > you're right. I have to add the following to make sure it will be called > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 2eb1aa8..9fc077c 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -7604,9 +7604,13 @@ static void update_blocked_averages(int cpu) > cpu, > cfs_rq == &rq->cfs ? 0 : (long)cfs_rq->tg ); > > - if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) > + if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) { > update_tg_load_avg(cfs_rq, 0); > > + if (cfs_rq == &rq->cfs) > + decayed = 1; > + } > + > trace_sched_load_contrib_blocked(cpu, > &cfs_rq->avg, > cfs_rq == &rq->cfs ? 0 : (long)cfs_rq->tg );
the proper fix without some debug trace events :-)
@@ -7567,9 +7569,13 @@ static void update_blocked_averages(int cpu) for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) { struct sched_entity *se; - if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) + if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) { update_tg_load_avg(cfs_rq, 0); + if (cfs_rq == &rq->cfs) + decayed = 1; + } + /* Propagate pending load changes to the parent, if any: */ se = cfs_rq->tg->se[cpu]; if (se && !skip_blocked_update(se))
> >
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