From: Mike Galbraith <efault@gmx.de>
To: Uladzislau Rezki <urezki@gmail.com>
Cc: Atish Patra <atish.patra@oracle.com>,
Peter Zijlstra <peterz@infradead.org>,
Joel Fernandes <joelaf@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Brendan Jackman <brendan.jackman@arm.com>,
Josef Bacik <jbacik@fb.com>, Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH RFC 1/2] sched: Minimize the idle cpu selection race window.
Date: Tue, 28 Nov 2017 11:49:11 +0100 [thread overview]
Message-ID: <1511866151.8472.51.camel@gmx.de> (raw)
In-Reply-To: <20171128093422.5hmrkonj3z6twy2y@pc636>
On Tue, 2017-11-28 at 10:34 +0100, Uladzislau Rezki wrote:
> On Fri, Nov 24, 2017 at 07:46:30PM +0100, Mike Galbraith wrote:
>
> > My view is you're barking up the wrong tree: you're making the idle
> > data SIS is using more accurate, but I question the benefit. That it
> > makes an imperfect placement decision occasionally due to raciness is
> > nearly meaningless compared to the cost of frequent bounce.
> Before sitting down and start testing, i just illustrated how we can
> apply claim_wake_up to ilb asking community a specific view on it:
> drawbacks, pros/cons, proposals etc.
Even if you make the thing atomic, what is ILB supposed to do, look
over its shoulder every step of the way and sh*t it's pants if somebody
touches claim_wake_up as it's about to or just after it did something?
If you intend to make all of LB race free, good luck.
-Mike
next prev parent reply other threads:[~2017-11-28 11:05 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-31 5:27 [PATCH RFC 0/2] Fix race window during idle cpu selection Atish Patra
2017-10-31 5:27 ` [PATCH RFC 1/2] sched: Minimize the idle cpu selection race window Atish Patra
2017-10-31 8:20 ` Peter Zijlstra
2017-10-31 8:48 ` Mike Galbraith
2017-11-01 6:08 ` Atish Patra
2017-11-01 6:54 ` Mike Galbraith
2017-11-01 7:18 ` Mike Galbraith
2017-11-01 16:36 ` Atish Patra
2017-11-01 20:20 ` Mike Galbraith
2017-11-05 0:58 ` Joel Fernandes
2017-11-22 5:23 ` Atish Patra
2017-11-23 10:52 ` Uladzislau Rezki
2017-11-23 13:13 ` Mike Galbraith
2017-11-23 16:00 ` Josef Bacik
2017-11-23 17:40 ` Mike Galbraith
2017-11-23 21:11 ` Atish Patra
2017-11-24 10:26 ` Uladzislau Rezki
2017-11-24 18:46 ` Mike Galbraith
2017-11-26 20:58 ` Mike Galbraith
2017-11-28 9:34 ` Uladzislau Rezki
2017-11-28 10:49 ` Mike Galbraith [this message]
2017-11-29 10:41 ` Uladzislau Rezki
2017-11-29 18:15 ` Mike Galbraith
2017-11-30 12:30 ` Uladzislau Rezki
2017-10-31 5:27 ` [PATCH DEBUG 2/2] sched: Add a stat for " Atish Patra
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