From: Patrick Bellasi <patrick.bellasi@arm.com>
To: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
"open list:THERMAL" <linux-pm@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Joel Fernandes <joelaf@google.com>,
Steve Muckle <smuckle@google.com>, Todd Kjos <tkjos@google.com>
Subject: Re: [PATCH 2/2] sched/fair: util_est: add running_sum tracking
Date: Tue, 5 Jun 2018 17:54:31 +0100 [thread overview]
Message-ID: <20180605165431.GF32302@e110439-lin> (raw)
In-Reply-To: <20180605153105.GM16081@localhost.localdomain>
On 05-Jun 17:31, Juri Lelli wrote:
> On 05/06/18 16:11, Patrick Bellasi wrote:
>
> [...]
>
> > If I run an experiment with your example above, while using the
> > performance governor to rule out any possible scale invariance
> > difference, here is what I measure:
> >
> > Task1 (40ms delayed by the following Task2):
> > mean std max
> > running_avg 455.387449 22.940168 492.0
> > util_avg 433.233288 17.395477 458.0
> >
> > Task2 (waking up at same time of Task1 and running before):
> > mean std max
> > running_avg 430.281834 22.405175 455.0
> > util_avg 421.745331 22.098873 456.0
> >
> > and if I compare Task1 above with another experiment where Task1 is
> > running alone:
> >
> > Task1 (running alone):
> > mean std min
> > running_avg 460.257895 22.103704 460.0
> > util_avg 435.119737 17.647556 461.0
>
> Wait, why again in this last case running_avg != util_avg? :)
I _think_ it's mostly due to the rouding errors we have because of the
reasons I've explained in the reply to Joel:
https://lkml.org/lkml/2018/6/5/559
20180605152156.GD32302@e110439-lin
at the end, while commenting about the division overhead.
I should try the above examples while tracking the full signal at
___update_load_avg() time.
--
#include <best/regards.h>
Patrick Bellasi
next prev parent reply other threads:[~2018-06-05 16:54 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-04 16:05 [PATCH 0/2] Improve estimated utilization of preempted FAIR tasks Patrick Bellasi
2018-06-04 16:05 ` [PATCH 1/2] sched/fair: pelt: use u32 for util_avg Patrick Bellasi
2018-06-05 1:30 ` kbuild test robot
2018-06-05 1:34 ` kbuild test robot
2018-06-04 16:06 ` [PATCH 2/2] sched/fair: util_est: add running_sum tracking Patrick Bellasi
2018-06-04 17:46 ` Joel Fernandes
2018-06-05 15:21 ` Patrick Bellasi
2018-06-05 19:33 ` Joel Fernandes
2018-06-05 19:43 ` Joel Fernandes
2018-06-05 1:29 ` kbuild test robot
2018-06-05 6:57 ` Vincent Guittot
2018-06-05 15:11 ` Patrick Bellasi
2018-06-05 15:31 ` Juri Lelli
2018-06-05 16:54 ` Patrick Bellasi [this message]
2018-06-05 20:46 ` Joel Fernandes
2018-06-05 23:15 ` Saravana Kannan
2018-06-06 8:26 ` Vincent Guittot
2018-06-06 10:38 ` Patrick Bellasi
2018-06-05 10:46 ` kbuild test robot
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