linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Vincent Guittot <vincent.guittot@linaro.org>
To: Lukasz Luba <lukasz.luba@arm.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
	Chris Redpath <Chris.Redpath@arm.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Quentin Perret <qperret@google.com>,
	"open list:THERMAL" <linux-pm@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	segall@google.com, Mel Gorman <mgorman@suse.de>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	CCj.Yeh@mediatek.com
Subject: Re: [PATCH 1/3] sched/fair: Prepare variables for increased precision of EAS estimated energy
Date: Wed, 7 Jul 2021 12:50:15 +0200	[thread overview]
Message-ID: <CAKfTPtCy-dbo0xnW8iKaQy94_iV=JYbMU-X4qanzL6RXcL7xEw@mail.gmail.com> (raw)
In-Reply-To: <58cb7ad3-ffff-8940-4c8e-2c46dcc86d54@arm.com>

On Wed, 7 Jul 2021 at 12:41, Lukasz Luba <lukasz.luba@arm.com> wrote:
>
>
>
> On 7/7/21 11:32 AM, Vincent Guittot wrote:
> > On Wed, 7 Jul 2021 at 12:29, Lukasz Luba <lukasz.luba@arm.com> wrote:
> >>
> >>
> >>
> >> On 7/7/21 11:11 AM, Vincent Guittot wrote:
> >>> On Wed, 7 Jul 2021 at 12:06, Lukasz Luba <lukasz.luba@arm.com> wrote:
> >>>>
> >>
> >> [snip]
> >>
> >>>> No. It's in 0.1uW scale, so 800Watts. Which is 16 CPUs * 64Watts
> >>>
> >>> Oh! you want 0.1uW precision .... This doesn't seem realistic at all.
> >>> I'm not even sure that the power model can even reach an accuracy of
> >>> 1mW
> >>>
> >>
> >> True, the EM is registering platform with 1mW precision, but 1uW
> >
> > Do you mean 1uW or 0.1uW ?
>
> In this patch set I've proposed 0.1uW, but I'm open to drop one
> order of magnitude. The 1uW still be good.

I don't want to underestimate the capabilities of the power model but
I don't see which benefit you will get with 0.1uW precision
With a 1uW precision the long type currently used for the returned
value is fine for 32bits machine AFAICT

  reply	other threads:[~2021-07-07 10:50 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-25 15:26 [PATCH 0/3] Improve EAS energy estimation and increase precision Lukasz Luba
2021-06-25 15:26 ` [PATCH 1/3] sched/fair: Prepare variables for increased precision of EAS estimated energy Lukasz Luba
2021-06-30 17:01   ` Rafael J. Wysocki
2021-06-30 17:28     ` Lukasz Luba
2021-07-02 19:07       ` Lukasz Luba
2021-07-07  7:07   ` Vincent Guittot
2021-07-07  7:49     ` Lukasz Luba
2021-07-07  8:00       ` Vincent Guittot
2021-07-07  8:23         ` Lukasz Luba
2021-07-07  9:37           ` Vincent Guittot
2021-07-07  9:48             ` Lukasz Luba
2021-07-07  9:56               ` Vincent Guittot
2021-07-07 10:06                 ` Lukasz Luba
2021-07-07 10:11                   ` Vincent Guittot
2021-07-07 10:29                     ` Lukasz Luba
2021-07-07 10:32                       ` Vincent Guittot
2021-07-07 10:41                         ` Lukasz Luba
2021-07-07 10:50                           ` Vincent Guittot [this message]
2021-07-07 11:02                             ` Lukasz Luba
2021-07-07 13:53                               ` Vincent Guittot
2021-07-07 14:25                                 ` Lukasz Luba
2021-07-07  9:45           ` Dietmar Eggemann
2021-07-07  9:54             ` Lukasz Luba
2021-06-25 15:26 ` [PATCH 2/3] PM: EM: Make em_cpu_energy() able to return bigger values Lukasz Luba
2021-07-05 12:44   ` Dietmar Eggemann
2021-07-06 19:44     ` Lukasz Luba
2021-07-07  7:07   ` Peter Zijlstra
2021-07-07  8:09     ` Lukasz Luba
2021-07-07 10:01       ` Peter Zijlstra
2021-07-07 10:23         ` Lukasz Luba
2021-06-25 15:26 ` [PATCH 3/3] PM: EM: Increase energy calculation precision Lukasz Luba
2021-07-05 12:45   ` Dietmar Eggemann
2021-07-06 19:51     ` Lukasz Luba

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='CAKfTPtCy-dbo0xnW8iKaQy94_iV=JYbMU-X4qanzL6RXcL7xEw@mail.gmail.com' \
    --to=vincent.guittot@linaro.org \
    --cc=CCj.Yeh@mediatek.com \
    --cc=Chris.Redpath@arm.com \
    --cc=bristot@redhat.com \
    --cc=dietmar.eggemann@arm.com \
    --cc=juri.lelli@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=lukasz.luba@arm.com \
    --cc=mgorman@suse.de \
    --cc=mingo@redhat.com \
    --cc=morten.rasmussen@arm.com \
    --cc=peterz@infradead.org \
    --cc=qperret@google.com \
    --cc=rjw@rjwysocki.net \
    --cc=rostedt@goodmis.org \
    --cc=segall@google.com \
    --cc=viresh.kumar@linaro.org \
    --subject='Re: [PATCH 1/3] sched/fair: Prepare variables for increased precision of EAS estimated energy' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).