From: Steven Rostedt <rostedt@goodmis.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Tejun Heo <tj@kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
pjt@google.com, paul.mckenney@linaro.org, tglx@linutronix.de,
suresh.b.siddha@intel.com, venki@google.com, mingo@redhat.com,
peterz@infradead.org, Arvind.Chauhan@arm.com,
linaro-dev@lists.linaro.org, patches@linaro.org,
pdsw-power-team@arm.com, linux-kernel@vger.kernel.org,
linux-rt-users@vger.kernel.org
Subject: Re: [PATCH V2 Resend 3/4] workqueue: Schedule work on non-idle cpu instead of current one
Date: Mon, 07 Jan 2013 17:29:55 -0500 [thread overview]
Message-ID: <1357597795.5190.10.camel@gandalf.local.home> (raw)
In-Reply-To: <CAKohpom9DxoojtcpMfmyGeUcEw8=tsS4n+TFMRV3+9_UBaod7g@mail.gmail.com>
On Mon, 2013-01-07 at 23:29 +0530, Viresh Kumar wrote:
> > By default, I would suggest for cache locality,
> > that we try to keep it on the same CPU. But if there's a better CPU to
> > run on, it runs there.
>
> That would break our intention behind this routine. We should run
> it on a cpu which we think is the best one for it power/performance wise.
If you are running on a big.Little box sure. But for normal (read x86 ;)
systems, it should probably stay on the current CPU.
>
> So, i would like to call the sched_select_cpu() routine from this routine to
> get the suggested cpu.
Does the caller need to know? Or if you have a big.LITTLE setup, it
should just work automagically?
>
> This routine would however would see more changes later to optimize it
> more.
>
> > Also, we could still add a debug option that
> > makes it always run on other CPUs to slap developers that don't read.
>
> I don't think we need it :(
> It would be a new API, with zero existing users. And so, whomsoever uses
> it, should know what exactly he is doing :)
Heh, you don't know kernel developers well do you? ;-)
Once a new API is added to the kernel tree, it quickly becomes
(mis)used.
-- Steve
next prev parent reply other threads:[~2013-01-07 22:29 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 [this message]
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
2012-11-26 19:17 ` Steven Rostedt
2012-11-27 6:25 ` Viresh Kumar
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