Re: [PATCHSET] workqueue: reimplement CPU hotplug to keep idleworkers

From: Tejun Heo
Date: Fri Jul 20 2012 - 15:41:14 EST


Hello, Rafael.

On Fri, Jul 20, 2012 at 09:44:04PM +0200, Rafael J. Wysocki wrote:
> Well, there are use cases I'm not really familiar with.
>
> Pretty much the only use case I'm sufficiently familiar with is
> suspend/hibernate where we unplug all of the nonboot CPUs at one point.
>
> The other use cases, which I don't really think are entirely valid,
> are on some ARM platforms where CPUs are unplugged instead of being put into
> C-states or equivalent (because we don't have a good mechanism for handling
> multiprocessor C-states; there's a set of patches for that waiting for
> the merge window in the Len's tree). I'm hoping to get rid of those
> use cases in future entirely.

I see, so the highest frequency user would most likely be
suspend/resume - especially with opportunistic approach like the one
used in androids.

Thanks for the explanation.

--
tejun
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