From: Peter Zijlstra <peterz@infradead.org>
To: Juri Lelli <Juri.Lelli@arm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
Rafael Wysocki <rjw@rjwysocki.net>,
Ingo Molnar <mingo@redhat.com>,
linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
Robin Randhawa <robin.randhawa@arm.com>,
Steve Muckle <smuckle.linux@gmail.com>,
tkjos@google.com, Morten Rasmussen <morten.rasmussen@arm.com>
Subject: Re: [PATCH] cpufreq: schedutil: add up/down frequency transition rate limits
Date: Mon, 21 Nov 2016 15:43:43 +0100 [thread overview]
Message-ID: <20161121144343.GH3092@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20161121143727.GO24383@e106622-lin>
On Mon, Nov 21, 2016 at 02:37:27PM +0000, Juri Lelli wrote:
> On 21/11/16 15:17, Peter Zijlstra wrote:
> > Not sure I follow. So by limiting decay to the task value, the moment we
> > add it back to the accumulated signal (wakeup), the accumulated signal
> > jumps up quickly and ramp-up is achieved.
> >
>
> This is true, but it seems that this potentially spiky behaviour
> (which in general depends on tasks composition and periodicity) might
> affect power savings (as in you don't generally want to switch between
> high and low freqs too often). So that's why I was just thinking that
> some sort of smoothing applied to the signal schedutil uses might help.
Hurm.. so during LPC it was said that fast ramp-up was desired. Note
that we'll not ramp down this fast, the accumulated signal will decay
slowly as per blocked-load PELT rules. So only ramp-up is spiky, but
that is what was desired AFAIU.
next prev parent reply other threads:[~2016-11-21 14:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-17 5:18 Viresh Kumar
2016-11-21 10:08 ` Viresh Kumar
2016-11-21 10:19 ` Peter Zijlstra
2016-11-21 10:48 ` Viresh Kumar
2016-11-21 11:12 ` Peter Zijlstra
2016-11-21 11:30 ` Viresh Kumar
2016-11-21 11:48 ` Peter Zijlstra
2016-11-21 12:14 ` Juri Lelli
2016-11-21 12:26 ` Peter Zijlstra
2016-11-21 13:53 ` Juri Lelli
2016-11-21 14:17 ` Peter Zijlstra
2016-11-21 14:37 ` Juri Lelli
2016-11-21 14:43 ` Peter Zijlstra [this message]
2016-11-21 14:59 ` Juri Lelli
2016-11-22 9:27 ` Vincent Guittot
2016-11-22 11:03 ` Patrick Bellasi
2016-11-21 14:59 ` Patrick Bellasi
2016-11-21 15:26 ` Peter Zijlstra
2016-11-21 15:34 ` Peter Zijlstra
2016-11-21 16:24 ` Patrick Bellasi
2016-11-21 16:46 ` Peter Zijlstra
2016-11-21 20:53 ` Rafael J. Wysocki
2016-12-29 3:24 ` Wanpeng Li
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20161121144343.GH3092@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=Juri.Lelli@arm.com \
--cc=linaro-kernel@lists.linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=morten.rasmussen@arm.com \
--cc=rjw@rjwysocki.net \
--cc=robin.randhawa@arm.com \
--cc=smuckle.linux@gmail.com \
--cc=tkjos@google.com \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome