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Date: Fri, 14 Jul 2017 17:58:53 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: "Li, Aubrey" <aubrey.li@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
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Subject: Re: [RFC PATCH v1 00/11] Create fast idle path for short idle periods
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On Fri, Jul 14, 2017 at 08:52:28AM -0700, Arjan van de Ven wrote:
> On 7/14/2017 8:38 AM, Peter Zijlstra wrote:
> > No, that's wrong. We want to fix the normal C state selection process to
> > pick the right C state.
> > 
> > The fast-idle criteria could cut off a whole bunch of available C
> > states. We need to understand why our current C state pick is wrong and
> > amend the algorithm to do better. Not just bolt something on the side.
> 
> I can see a fast path through selection if you know the upper bound of any
> selection is just 1 state.
> 
> But also, how much of this is about "C1 be fast" versus "selecting C1 is slow"

I got the impression its about we need to select C1 for longer. But the
fact that the patches don't in fact answer any of these questions,
they're wrong in principle ;-)