From: Viresh Kumar <viresh.kumar@linaro.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Lists linaro-kernel <linaro-kernel@lists.linaro.org>,
Linux PM <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: [PATCH 3/3] cpufreq: schedutil: remove redundant code from sugov_next_freq_shared()
Date: Tue, 7 Mar 2017 16:01:08 +0530 [thread overview]
Message-ID: <20170307103108.GA4526@vireshk-i7> (raw)
In-Reply-To: <CAJZ5v0hov8Lz_MK9dxP9MyqSmPNRfWV9Wia4DtAZtOPmoTOqAw@mail.gmail.com>
On 06-03-17, 13:24, Rafael J. Wysocki wrote:
> On Mon, Mar 6, 2017 at 5:45 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> > On 04-03-17, 01:11, Rafael J. Wysocki wrote:
> >> So one idea is that if SCHED_CPUFREQ_RT_DL is set in flags, we don't even
> >> need to start the loop which is quite a cost to simply notice that there's
> >> nothing to do.
> >
> > Hmm. Isn't the probability of this flag being set, same for all CPUs in the
> > policy?
>
> No, I don't think so.
Why do you think so? I thought all CPU in the policy can have the RT/DL flag set
and the probability of all of them is just the same.
> So to the point, the code was written this way on purpose and not just
> by accident as your changelog suggests and
I didn't wanted to convey that really and I knew that it was written on purpose.
> if you want to change it, you need numbers.
What kind of numbers can we get for such a change ? I tried to take the running
average of the time it takes to execute this routine over 10000 samples, but it
varies a lot even with the same build. Any tests like hackbench, etc wouldn't be
of any help as well.
--
viresh
next prev parent reply other threads:[~2017-03-07 10:32 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-02 8:33 [PATCH 0/3] cupfreq: schedutil: Minor fix and cleanups Viresh Kumar
2017-03-02 8:33 ` [PATCH 1/3] cpufreq: schedutil: move cached_raw_freq to struct sugov_policy Viresh Kumar
2017-03-02 22:05 ` Rafael J. Wysocki
2017-03-03 3:07 ` Viresh Kumar
2017-03-02 8:33 ` [PATCH 2/3] cpufreq: schedutil: Pass sg_policy to get_next_freq() Viresh Kumar
2017-03-02 8:33 ` [PATCH 3/3] cpufreq: schedutil: remove redundant code from sugov_next_freq_shared() Viresh Kumar
2017-03-04 0:03 ` Rafael J. Wysocki
2017-03-04 0:11 ` Rafael J. Wysocki
2017-03-06 4:45 ` Viresh Kumar
2017-03-06 12:24 ` Rafael J. Wysocki
2017-03-07 10:31 ` Viresh Kumar [this message]
2017-03-07 13:19 ` Rafael J. Wysocki
2017-03-08 4:18 ` Viresh Kumar
2017-03-08 10:50 ` Rafael J. Wysocki
2017-03-08 11:15 ` Viresh Kumar
2017-03-08 12:54 ` Rafael J. Wysocki
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