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From: Quentin Perret <qperret@google.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	dietmar.eggemann@arm.com, patrick.bellasi@matbug.net,
	lenb@kernel.org, linux-kernel@vger.kernel.org,
	valentin.schneider@arm.com, ionela.voinescu@arm.com
Subject: Re: [RFC] Documentation/scheduler/schedutil.txt
Date: Fri, 20 Nov 2020 09:27:24 +0000	[thread overview]
Message-ID: <20201120092724.GB2653684@google.com> (raw)
In-Reply-To: <20201120091904.6zvovj2yxjxtnq2x@vireshk-i7>

On Friday 20 Nov 2020 at 14:49:04 (+0530), Viresh Kumar wrote:
>     This is unlikely to be an issue on systems where cpufreq policies are
>     shared between multiple CPUs, because in those cases the policy
>     utilization is computed as the maximum of the CPU utilization values
>     over the whole policy and if that turns out to be low, reducing the
>     frequency for the policy most likely is a good idea anyway.

Hmm, I'm not sure I agree with this actually. We may be migrating the
task to a different policy altogether. And even if we migrate to another
CPU in the current policy, the task util_avg may be small just because
it was packed with other tasks on a rq, which means it may not increase
the util of the destination rq by much.

ISTR Douglas' EM-based schedutil boosting series was addressing that at
some point, I'll go have a look back at that discussion...

  reply	other threads:[~2020-11-20  9:27 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-20  7:55 [RFC] Documentation/scheduler/schedutil.txt Peter Zijlstra
2020-11-20  8:56 ` Peter Zijlstra
2020-11-20  9:13   ` Quentin Perret
2020-11-20  9:19     ` Viresh Kumar
2020-11-20  9:27       ` Quentin Perret [this message]
2020-11-23  9:30   ` Dietmar Eggemann
2020-11-23 10:05     ` Vincent Guittot
2020-11-23 11:27       ` Dietmar Eggemann
2020-11-23 13:42         ` Vincent Guittot
2020-11-23 18:39           ` Dietmar Eggemann
2020-11-20 11:45 ` Valentin Schneider
2020-11-20 14:37 ` Morten Rasmussen
2020-11-23  9:26 ` Dietmar Eggemann
2020-11-23 14:51   ` Peter Zijlstra
2020-12-02 14:18 ` Mel Gorman
2020-12-02 15:54   ` Peter Zijlstra
2020-12-02 16:45     ` Mel Gorman
2020-12-02 16:58       ` Peter Zijlstra

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