Re: [discussion]sched: a rough proposal to enable power saving inscheduler

From: Matthew Garrett
Date: Mon Aug 20 2012 - 14:17:01 EST


On Mon, Aug 20, 2012 at 10:06:06AM +0200, Ingo Molnar wrote:

> If the answer is 'yes' then there's clear cases where the kernel
> (should) automatically know the events where we switch from
> balancing for performance to balancing for power:

No. We can't identify all of these cases and we can't identify corner
cases. Putting this kind of policy in the kernel is an awful idea. It
should never be altering policy itself, because it'll get it wrong and
people will file bugs complaining that it got it wrong and the biggest
case where you *need* to be able to handle switching between performance
and power optimisations (your rack management unit just told you that
you're going to have to drop power consumption by 20W) is one where the
kernel doesn't have all the information it needs to do this. So why
bother at all?

--
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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