linux-kernel - Re: [PATCH V3 3/7] workqueue: Add helpers to schedule work on any cpu

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Message-ID: <20130328181332.GD14088@htj.dyndns.org>
Date:	Thu, 28 Mar 2013 11:13:32 -0700
From:	Tejun Heo <tj@...nel.org>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	pjt@...gle.com, paul.mckenney@...aro.org, tglx@...utronix.de,
	suresh.b.siddha@...el.com, venki@...gle.com, mingo@...hat.com,
	peterz@...radead.org, rostedt@...dmis.org,
	linaro-kernel@...ts.linaro.org, robin.randhawa@....com,
	Steve.Bannister@....com, Liviu.Dudau@....com,
	charles.garcia-tobin@....com, Arvind.Chauhan@....com,
	linux-rt-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V3 3/7] workqueue: Add helpers to schedule work on any cpu

On Thu, Mar 21, 2013 at 11:29:37AM -0700, Tejun Heo wrote:
> Yes, I actually like that part a lot although I do wish the idle check
> was inlined.
> 
> What I'm wondering is whether the kinda out-of-band decision via
> sched_select_cpu() is justified given that it can and is likely to go
> through full scheduling decision anyway.  For timer, we don't have
> that, so it makes sense.  For work items, it's a bit different.
> 
> To rephrase, *if* the scheduler can't already make proper decisions
> regarding power consumption on an idlish system, maybe it can be
> improved to do so?  It could as well be that this CPU selection is
> special enough that it's just better to keep it separate as this
> patchset proposes.  This is something up to the scheduler people.
> Peter, Ingo, what do you guys think?

Ping.  Peter, Ingo?

Viresh, would it be difficult to make another measurement of the same
workload with the said workqueues converted to unbound?  I think that
would at least provide a nice reference point.

Thanks.

-- 
tejun
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