From: Vincent Guittot <vincent.guittot@linaro.org>
To: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
"open list:THERMAL" <linux-pm@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Juri Lelli <juri.lelli@redhat.com>,
Joel Fernandes <joelaf@google.com>,
Steve Muckle <smuckle@google.com>
Subject: Re: [PATCH v2 2/3] sched/fair: util_est: update before schedutil
Date: Mon, 14 May 2018 11:20:53 +0200 [thread overview]
Message-ID: <CAKfTPtB_qJn5erf6oqtu9sMS045keTz5Y0VKRifdThMfUGtXpg@mail.gmail.com> (raw)
In-Reply-To: <20180511131509.16275-3-patrick.bellasi@arm.com>
Hi Patrick,
On 11 May 2018 at 15:15, Patrick Bellasi <patrick.bellasi@arm.com> wrote:
> When a task is enqueue the estimated utilization of a CPU is updated
> to better support the selection of the required frequency.
> However, schedutil is (implicitly) updated by update_load_avg() which
> always happens before util_est_{en,de}queue(), thus potentially
> introducing a latency between estimated utilization updates and
> frequency selections.
>
> Let's update util_est at the beginning of enqueue_task_fair(),
> which will ensure that all schedutil updates will see the most
> updated estimated utilization value for a CPU.
>
> Reported-by: Vincent Guittot <vincent.guittot@linaro.org>
> Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Vincent Guittot <vincent.guittot@linaro.org>
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-pm@vger.kernel.org
> Fixes: 7f65ea42eb00 ("sched/fair: Add util_est on top of PELT")
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
>
> ---
>
> Changes in v2:
> - improve comment in enqueue_task_fair() (Peter)
> - add "Fixes" tag
> - add "Acked-by" Viresh tag
> ---
next prev parent reply other threads:[~2018-05-14 9:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-11 13:15 [PATCH v2 0/3] Improve schedutil integration for FAIR tasks Patrick Bellasi
2018-05-11 13:15 ` [PATCH v2 1/3] sched/cpufreq: always consider blocked FAIR utilization Patrick Bellasi
2018-05-14 9:16 ` Vincent Guittot
2018-05-14 16:48 ` Patrick Bellasi
2018-05-15 6:21 ` Vincent Guittot
2018-05-11 13:15 ` [PATCH v2 2/3] sched/fair: util_est: update before schedutil Patrick Bellasi
2018-05-14 9:20 ` Vincent Guittot [this message]
2018-05-11 13:15 ` [PATCH v2 3/3] sched/fair: schedutil: explicit update only when required Patrick Bellasi
2018-05-15 10:12 ` Vincent Guittot
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