From: Viresh Kumar <viresh.kumar@linaro.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Lukasz Luba <lukasz.luba@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Zhang Rui <rui.zhang@intel.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Amit Daniel Kachhap <amit.kachhap@gmail.com>,
Javi Merino <javi.merino@kernel.org>,
Amit Kucheria <amit.kucheria@verdurent.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Quentin Perret <qperret@google.com>,
Rafael Wysocki <rjw@rjwysocki.net>,
"open list:THERMAL" <linux-pm@vger.kernel.org>
Subject: Re: [PATCH 2/2] thermal: cpufreq_cooling: Reuse effective_cpu_util()
Date: Thu, 30 Jul 2020 11:54:14 +0530 [thread overview]
Message-ID: <20200730062414.uq3ip7ukpu7nkiyg@vireshk-mac-ubuntu> (raw)
In-Reply-To: <CAKfTPtA+BPegK2h6PQMFs+p4dpxO+sk1FDQuOfJvSpGCJ-rBrA@mail.gmail.com>
On 17-07-20, 11:46, Vincent Guittot wrote:
> On Thu, 16 Jul 2020 at 16:24, Lukasz Luba <lukasz.luba@arm.com> wrote:
> > On 7/16/20 12:56 PM, Peter Zijlstra wrote:
> > > Currently cpufreq_cooling appears to estimate the CPU energy usage by
> > > calculating the percentage of idle time using the per-cpu cpustat stuff,
> > > which is pretty horrific.
> >
> > Even worse, it then *samples* the *current* CPU frequency at that
> > particular point in time and assumes that when the CPU wasn't idle
> > during that period - it had *this* frequency...
>
> So there is 2 problems in the power calculation of cpufreq cooling device :
> - How to get an accurate utilization level of the cpu which is what
> this patch is trying to fix because using idle time is just wrong
> whereas scheduler utilization is frequency invariant
Since this patch is targeted only towards fixing this particular
problem, should I change something in the patch to make it acceptable
?
> - How to get power estimate from this utilization level. And as you
> pointed out, using the current freq which is not accurate.
This should be tackled separately I believe.
--
viresh
next prev parent reply other threads:[~2020-07-30 6:24 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 6:36 [PATCH 0/2] cpufreq_cooling: Get effective CPU utilization from scheduler Viresh Kumar
2020-07-14 6:36 ` [PATCH 1/2] sched/core: Rename and move schedutil_cpu_util to core.c Viresh Kumar
2020-07-14 12:52 ` Rafael J. Wysocki
2020-07-14 6:36 ` [PATCH 2/2] thermal: cpufreq_cooling: Reuse effective_cpu_util() Viresh Kumar
2020-07-14 8:23 ` Peter Zijlstra
2020-07-14 13:05 ` Rafael J. Wysocki
2020-07-15 7:32 ` Viresh Kumar
2020-07-15 12:47 ` Rafael J. Wysocki
2020-07-16 11:56 ` Peter Zijlstra
2020-07-16 14:24 ` Lukasz Luba
2020-07-16 15:43 ` Peter Zijlstra
2020-07-17 9:55 ` Lukasz Luba
2020-07-17 9:46 ` Vincent Guittot
2020-07-17 10:30 ` Lukasz Luba
2020-07-17 12:13 ` Vincent Guittot
2020-07-30 6:24 ` Viresh Kumar [this message]
2020-07-30 11:16 ` Lukasz Luba
2020-10-19 7:40 ` Viresh Kumar
2020-10-19 11:10 ` Lukasz Luba
2020-10-22 8:32 ` Viresh Kumar
2020-10-22 9:05 ` Peter Zijlstra
2020-10-22 11:06 ` Viresh Kumar
2020-10-22 11:30 ` Rafael J. Wysocki
2020-10-22 11:57 ` Peter Zijlstra
2020-10-22 12:07 ` Rafael J. Wysocki
2020-10-22 11:39 ` Peter Zijlstra
2020-07-17 10:14 ` Quentin Perret
2020-07-17 10:33 ` Quentin Perret
2020-07-17 10:43 ` Quentin Perret
2020-07-22 9:13 ` Viresh Kumar
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