From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux PM <linux-pm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Juri Lelli <juri.lelli@arm.com>,
Patrick Bellasi <patrick.bellasi@arm.com>,
Joel Fernandes <joelaf@google.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: [RFC][PATCH v2 2/2] cpufreq: schedutil: Avoid decreasing frequency of busy CPUs
Date: Tue, 21 Mar 2017 15:03:25 +0100 [thread overview]
Message-ID: <20170321140325.gf64gc7eaqu335t5@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtBp7GevDfnOTrOnrc79XP1mbY0onq=uh4Aw2tGu-DgHGw@mail.gmail.com>
On Tue, Mar 21, 2017 at 02:37:08PM +0100, Vincent Guittot wrote:
> On 21 March 2017 at 14:22, Peter Zijlstra <peterz@infradead.org> wrote:
> For the not overloaded case, it makes sense to immediately update to
> OPP to be aligned with the new utilization of the CPU even if it was
> not idle in the past couple of ticks
Yeah, but we cannot know. Also, who cares?
> > does exactly that. Note that the lack of idle time is an exact
> > equivalent of 100% utilized.
> >
> > So even while we cannot currently detect the 100% utilized state through
> > the running state tracking; because averages etc.. we can detect the
> > lack of idle time.
>
> But after how much lack of idle time do we consider that we are overloaded ?
0 :-)
Note that utilization is an absolute metric, not a windowed one. That
is, there is no actual time associated with it. Now, for practical
purposes we end up using windowed things in many places,
next prev parent reply other threads:[~2017-03-21 14:50 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-19 13:21 [PATCH 0/2] cpufreq: schedutil: Fix and optimization Rafael J. Wysocki
2017-03-19 13:30 ` [PATCH 1/2] cpufreq: schedutil: Fix per-CPU structure initialization in sugov_start() Rafael J. Wysocki
2017-03-20 3:28 ` Viresh Kumar
2017-03-20 12:36 ` Rafael J. Wysocki
2017-03-19 13:34 ` [RFC][PATCH 2/2] cpufreq: schedutil: Force max frequency on busy CPUs Rafael J. Wysocki
2017-03-19 21:24 ` Rafael J. Wysocki
2017-03-19 21:42 ` Rafael J. Wysocki
2017-03-20 10:38 ` Peter Zijlstra
2017-03-20 12:31 ` Rafael J. Wysocki
2017-03-20 3:57 ` Viresh Kumar
2017-03-20 8:26 ` Vincent Guittot
2017-03-20 12:34 ` Patrick Bellasi
2017-03-22 23:56 ` Joel Fernandes
2017-03-23 22:08 ` Vincent Guittot
2017-03-25 3:48 ` Joel Fernandes
2017-03-27 6:59 ` Vincent Guittot
2017-03-20 12:59 ` Rafael J. Wysocki
2017-03-20 13:20 ` Vincent Guittot
2017-03-20 12:48 ` Rafael J. Wysocki
2017-03-20 10:36 ` Peter Zijlstra
2017-03-20 12:35 ` Rafael J. Wysocki
2017-03-20 12:50 ` Peter Zijlstra
2017-03-20 13:04 ` Rafael J. Wysocki
2017-03-20 13:06 ` Patrick Bellasi
2017-03-20 13:05 ` Rafael J. Wysocki
2017-03-20 14:13 ` Patrick Bellasi
2017-03-20 21:46 ` [RFC][PATCH v2 2/2] cpufreq: schedutil: Avoid decreasing frequency of " Rafael J. Wysocki
2017-03-21 6:40 ` Viresh Kumar
2017-03-21 12:30 ` Rafael J. Wysocki
2017-03-21 8:50 ` Vincent Guittot
2017-03-21 11:56 ` Patrick Bellasi
2017-03-21 13:22 ` Peter Zijlstra
2017-03-21 13:37 ` Vincent Guittot
2017-03-21 14:03 ` Peter Zijlstra [this message]
2017-03-21 14:18 ` Vincent Guittot
2017-03-21 14:25 ` Patrick Bellasi
[not found] ` <CAKfTPtALorn7HNpz4LOfWWSc3u+9y5iHB5byzfTHGQXDA+tVJQ@mail.gmail.com>
2017-03-21 14:58 ` Peter Zijlstra
2017-03-21 17:00 ` Vincent Guittot
2017-03-21 17:01 ` Vincent Guittot
2017-03-21 14:26 ` Rafael J. Wysocki
2017-03-21 14:38 ` Patrick Bellasi
2017-03-21 14:46 ` Rafael J. Wysocki
2017-03-21 14:50 ` Rafael J. Wysocki
2017-03-21 15:04 ` Peter Zijlstra
2017-03-21 15:18 ` Rafael J. Wysocki
2017-03-21 17:00 ` Peter Zijlstra
2017-03-21 17:17 ` Rafael J. Wysocki
2017-03-21 15:08 ` Patrick Bellasi
2017-03-21 15:18 ` Peter Zijlstra
2017-03-21 19:28 ` Patrick Bellasi
2017-03-21 15:02 ` Peter Zijlstra
2017-03-21 11:50 ` Patrick Bellasi
2017-03-21 23:08 ` [RFC][PATCH v3 2/2] cpufreq: schedutil: Avoid reducing frequency of busy CPUs prematurely Rafael J. Wysocki
2017-03-22 9:26 ` Peter Zijlstra
2017-03-22 9:54 ` Viresh Kumar
2017-03-23 1:04 ` Joel Fernandes
2017-03-23 19:26 ` Sai Gurrappadi
2017-03-23 20:48 ` Sai Gurrappadi
2017-03-24 1:39 ` Rafael J. Wysocki
2017-03-24 19:08 ` Sai Gurrappadi
2017-03-25 1:14 ` Sai Gurrappadi
2017-03-25 1:39 ` Rafael J. Wysocki
2017-03-27 7:04 ` Vincent Guittot
2017-03-27 21:01 ` Sai Gurrappadi
2017-03-27 21:11 ` Rafael J. Wysocki
2017-05-08 3:49 ` Wanpeng Li
2017-05-08 4:01 ` Viresh Kumar
2017-05-08 5:15 ` Wanpeng Li
2017-05-08 22:16 ` Rafael J. Wysocki
2017-05-08 22:36 ` Wanpeng Li
2017-05-08 23:01 ` Rafael J. Wysocki
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