From: "Paul E. McKenney" <paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
To: Steven Rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>
Cc: venki-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org,
linaro-dev-cunTk1MwBs8s++Sfvej+rw@public.gmane.org,
suresh.b.siddha-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
patches-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org,
peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org,
Viresh Kumar
<viresh.kumar-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
paul.mckenney-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org,
mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
pdsw-power-team-5wv7dgnIgG8@public.gmane.org,
tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org,
pjt-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org,
linux-rt-users-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH V2 Resend 0/4] Create sched_select_cpu() and use it for workqueues and timers
Date: Mon, 26 Nov 2012 11:03:54 -0800 [thread overview]
Message-ID: <20121126190354.GJ2474@linux.vnet.ibm.com> (raw)
In-Reply-To: <1353951352.6276.43.camel-f9ZlEuEWxVcJvu8Pb33WZ0EMvNT87kid@public.gmane.org>
On Mon, Nov 26, 2012 at 12:35:52PM -0500, Steven Rostedt wrote:
> On Mon, 2012-11-26 at 09:03 -0800, Paul E. McKenney wrote:
>
>
> > If I understand correctly (though also suffering turkey OD), the idea is
> > to offload work to more energy-efficient CPUs.
>
> This is determined by a CPU that isn't running the idle task? Is it
> because a CPU that just woke up may be running at a lower freq, and thus
> not as efficient? But pushing off to another CPU may cause cache misses
> as well. Wouldn't that also be a factor in efficiencies, if a CPU is
> stalled waiting for memory to be loaded?
Two different microarchitectures -- same instruction set (at user level,
anyway), but different power/performance characteristics. One set is
optimized for performance, the other for energy efficiency. For example,
ARM's big.LITTLE architecture.
> I should also ask the obvious. Has these patches shown real world
> efficiencies or is this just a theory? Do these patches actually improve
> battery life when applied?
I must defer to Viresh on this one.
Thanx, Paul
> Just asking.
>
> -- Steve
>
>
next prev parent reply other threads:[~2012-11-26 19:03 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-06 10:34 [PATCH V2 Resend 0/4] Create sched_select_cpu() and use it for workqueues and timers Viresh Kumar
[not found] ` <cover.1352196505.git.viresh.kumar-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2012-11-06 10:38 ` [PATCH V2 Resend 1/4] sched: Create sched_select_cpu() to give preferred CPU for power saving Viresh Kumar
2012-11-06 10:38 ` [PATCH V2 Resend 2/4] timer: hrtimer: Don't check idle_cpu() before calling get_nohz_timer_target() Viresh Kumar
2012-11-06 10:38 ` [PATCH V2 Resend 4/4] timer: Migrate running timer Viresh Kumar
2012-11-27 13:47 ` Steven Rostedt
2013-03-20 15:13 ` Viresh Kumar
2013-04-09 14:52 ` Viresh Kumar
2013-04-24 11:22 ` Viresh Kumar
2013-05-13 9:19 ` Viresh Kumar
2013-05-13 10:35 ` Thomas Gleixner
2013-05-22 8:34 ` Viresh Kumar
2013-05-22 9:06 ` Peter Zijlstra
2013-05-22 9:23 ` Viresh Kumar
2013-05-31 10:49 ` Viresh Kumar
2013-06-18 4:51 ` Viresh Kumar
2013-07-24 9:17 ` Viresh Kumar
2013-08-07 9:55 ` Viresh Kumar
2013-10-04 12:39 ` Sebastian Andrzej Siewior
2013-10-23 5:55 ` Viresh Kumar
2012-11-06 10:38 ` [PATCH V2 Resend 3/4] workqueue: Schedule work on non-idle cpu instead of current one Viresh Kumar
[not found] ` <ad25c731a6ca1bd1269555245952f05c856a9759.1352196505.git.viresh.kumar-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2012-11-26 17:15 ` Tejun Heo
2012-11-27 5:19 ` Viresh Kumar
2012-11-27 12:54 ` Vincent Guittot
[not found] ` <CAKohpom9=K976NmyFWtXx2UQyRcLAqsoGw-5AaqXRpSL6uxP_g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-01-04 11:11 ` Viresh Kumar
2013-01-04 15:09 ` Tejun Heo
2013-01-07 9:58 ` Viresh Kumar
2013-01-07 13:28 ` Steven Rostedt
2013-01-07 17:59 ` Viresh Kumar
2013-01-07 22:29 ` Steven Rostedt
2013-01-08 4:03 ` Viresh Kumar
2013-01-07 15:04 ` Tejun Heo
2013-01-07 15:40 ` Amit Kucheria
2013-01-07 18:07 ` Viresh Kumar
2013-01-09 18:49 ` Tejun Heo
2013-01-10 5:04 ` Viresh Kumar
2012-11-27 13:26 ` Steven Rostedt
2012-11-27 13:48 ` Viresh Kumar
2012-11-27 13:59 ` Steven Rostedt
2012-11-27 14:55 ` Vincent Guittot
2012-11-27 15:04 ` Steven Rostedt
2012-11-27 15:35 ` Vincent Guittot
2012-11-26 15:00 ` [PATCH V2 Resend 0/4] Create sched_select_cpu() and use it for workqueues and timers Viresh Kumar
2012-11-26 16:40 ` Steven Rostedt
[not found] ` <1353948027.6276.38.camel-f9ZlEuEWxVcJvu8Pb33WZ0EMvNT87kid@public.gmane.org>
2012-11-26 17:03 ` Paul E. McKenney
2012-11-26 17:35 ` Steven Rostedt
[not found] ` <1353951352.6276.43.camel-f9ZlEuEWxVcJvu8Pb33WZ0EMvNT87kid@public.gmane.org>
2012-11-26 19:03 ` Paul E. McKenney [this message]
2012-11-26 19:17 ` Steven Rostedt
2012-11-27 6:25 ` Viresh Kumar
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=20121126190354.GJ2474@linux.vnet.ibm.com \
--to=paulmck-23vcf4htsmix0ybbhkvfkdbpr1lh4cv8@public.gmane.org \
--cc=linaro-dev-cunTk1MwBs8s++Sfvej+rw@public.gmane.org \
--cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-rt-users-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
--cc=patches-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org \
--cc=paul.mckenney-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org \
--cc=pdsw-power-team-5wv7dgnIgG8@public.gmane.org \
--cc=peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org \
--cc=pjt-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org \
--cc=rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org \
--cc=suresh.b.siddha-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \
--cc=tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org \
--cc=tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org \
--cc=venki-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org \
--cc=viresh.kumar-QSEj5FYQhm4dnm+yROfE0A@public.gmane.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;
as well as URLs for NNTP newsgroup(s).