linux-kernel - Re: [PATCH V3 3/5] cpufreq: ondemand: queue work for policy->cpus together

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Date:	Wed, 28 Oct 2015 07:38:20 +0100
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V3 3/5] cpufreq: ondemand: queue work for policy->cpus together

On Tuesday, October 13, 2015 01:39:03 PM Viresh Kumar wrote:
> Currently update_sampling_rate() runs over each online CPU and
> cancels/queues work on it. Its very inefficient for the case where a
> single policy manages multiple CPUs, as they can be processed together.

In the case of one policy object shared between multiple CPUs, I'm
wondering why we don't use a single delayed work function for all of them
in the first place.  That would address the problem at the source instead
of dealing with the symptoms.

> Also drop the unnecessary cancel_delayed_work_sync() as we are doing a
> mod_delayed_work_on() in gov_queue_work(), which will take care of
> pending works for us.

I'd prefer a separate patch for that if poss.

Thanks,
Rafael

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