linux-kernel - Re: [PATCH RFC 1/2] sched: Minimize the idle cpu selection race window.

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Date:   Wed, 01 Nov 2017 08:18:03 +0100
From:   Mike Galbraith <efault@....de>
To:     Atish Patra <atish.patra@...cle.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     linux-kernel@...r.kernel.org, joelaf@...gle.com,
        brendan.jackman@....com, jbacik@...com, mingo@...hat.com
Subject: Re: [PATCH RFC 1/2] sched: Minimize the idle cpu selection race
 window.

On Wed, 2017-11-01 at 07:54 +0100, Mike Galbraith wrote:
> On Wed, 2017-11-01 at 01:08 -0500, Atish Patra wrote:
> 
> > Do you have the schbench configuration somewhere that I can test? I 
> > tried various configurations but did not
> > see any improvement or regression.
> 
> No, as noted, I didn't save anything.  I watched and fiddled with
> several configurations on various sized boxen, doing this/that on top
> of the reservation thing to try to improve the "it's 100% about perfect
> spread" schbench, but didn't like the pricetag, so tossed the lot over
> my shoulder and walked away.

BTW, the biggest trouble with schbench at that time was not so much
about wakeup time stacking (though it was visible), it was using load
averages instead of instantaneous state, and sawtoothing therein.

	-Mike