Re: sched: deep power-saving states

From: Arjan van de Ven
Date: Wed Oct 22 2008 - 09:47:39 EST

On Wed, 22 Oct 2008 09:42:52 -0400
Gregory Haskins <> wrote:

> What I was thinking is that a simple mechanism to quantify the
> power-state penalty would be to add those states as priority levels in
> the cpupri namespace. E.g. We could substitute IDLE-RUNNING for IDLE,
> and add IDLE-PS1, IDLE-PS2, .. IDLE-PSn, OTHER, RT1, .. RT99. This
> means the scheduler would favor waking an IDLE-RUNNING core over an
> IDLE-PS1-PSn, etc. The question in my mind is: can the power-states
> be determined in a static fashion such that we know what value to
> quantify the idle state before we enter it? Or is it more dynamic
> (e.g. the longer it is in an MWAIT, the deeper the sleep gets).

it's a little dynamic, but just assuming the worst will be a very good
approximation of reality. And we know what we're getting into in that

Arjan van de Ven Intel Open Source Technology Centre
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