Re: [RFT][PATCH v7 0/8] sched/cpuidle: Idle loop rework

From: Rafael J. Wysocki
Date: Wed Mar 21 2018 - 09:55:16 EST


On Wednesday, March 21, 2018 1:31:07 PM CET Rik van Riel wrote:
> On Tue, 2018-03-20 at 16:12 +0100, Rafael J. Wysocki wrote:
> > Hi All,
> >
> > Thanks a lot for the feedback so far!
> >
> > Respin after recent comments from Peter.
> >
> > Patches [1-3] unmodified since v5, patch 4 is new and the other ones
> > have been updated to address feedback.
> >
> > The previous summary that still applies:

Thanks for the testing!

> For some reason I see increased CPU utilization
> with this patch series (75% -> 85%) with the same
> rate of requests being handled by the vanilla
> kernel and a kernel with these patches applied.
>
> I am running a bisect in the series to see what
> change could possibly cause that,

The first 4 patches in the v7 should not change functionality by
themselves.

If you replace the original [5/8] with the v7.2 of it I've just
posted (https://patchwork.kernel.org/patch/10299429/), then it
should not change functionality by itself too.

Then you only have 3 patches to check. :-)

> and also digging
> through system statistics to see whether it might
> be something as perverse as not mistakenly choosing
> deeper C-states on one core causing other cores to
> miss out on turbo mode...

I have no idea ATM. And what's the workload?