From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mel Gorman <mgorman@suse.de>, Doug Smythies <dsmythies@telus.net>,
"open list:THERMAL" <linux-pm@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Sargun Dhillon <sargun@sargun.me>, Tejun Heo <tj@kernel.org>,
Xie XiuQi <xiexiuqi@huawei.com>,
xiezhipeng1@huawei.com,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Subject: Re: [PATCH v2] sched/freq: move call to cpufreq_update_util
Date: Wed, 13 Nov 2019 15:09:47 +0100 [thread overview]
Message-ID: <bcba52bc-6780-1efc-6ef4-1a75f1cef33d@arm.com> (raw)
In-Reply-To: <CAKfTPtBMNnM2tTfb72VtufDpwBvqu6Ttj3dnLgoNOZ--Q6qo+Q@mail.gmail.com>
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.
next prev parent reply other threads:[~2019-11-13 14:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1573570093-1340-1-git-send-email-vincent.guittot@linaro.org>
2019-11-12 15:05 ` [PATCH v2] sched/freq: move call to cpufreq_update_util Vincent Guittot
2019-11-12 17:11 ` Valentin Schneider
2019-11-12 17:20 ` Vincent Guittot
2019-11-12 17:44 ` Valentin Schneider
2019-11-13 10:49 ` Dietmar Eggemann
2019-11-13 13:30 ` Vincent Guittot
2019-11-13 14:09 ` Dietmar Eggemann [this message]
2019-11-13 17:50 ` Vincent Guittot
2019-11-13 18:09 ` Vincent Guittot
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