From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Mike Galbraith <efault@gmx.de>
Cc: lkml <linux-kernel@vger.kernel.org>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Paul Turner <pjt@google.com>,
Arjan Van De Ven <arjan@linux.intel.com>
Subject: Re: [patch v3] sched: fix select_idle_sibling() induced bouncing
Date: Mon, 11 Jun 2012 19:22:11 +0200 [thread overview]
Message-ID: <1339435331.31548.19.camel@twins> (raw)
In-Reply-To: <1339433835.7358.30.camel@marge.simpson.net>
On Mon, 2012-06-11 at 18:57 +0200, Mike Galbraith wrote:
> Traversing an entire package is not only expensive, it also leads to tasks
> bouncing all over a partially idle and possible quite large package. Fix
> that up by assigning a 'buddy' CPU to try to motivate. Each buddy may try
> to motivate that one other CPU, if it's busy, tough, it may then try it's
> SMT sibling, but that's all this optimization is allowed to cost.
>
> Sibling cache buddies are cross-wired to prevent bouncing.
>
> Signed-off-by: Mike Galbraith <efault@gmx.de>
The patch could do with a little comment on how you achieve the
cross-wiring because staring at the code I go cross-eyed again ;-)
Anyway, I think I'll grab it since nobody seems to have any objections
and the numbers seem good.
PJT any progress on your load-tracking stuff? Arjan is interested in the
avg runtime estimation it has to make the whole wake an idle thing
conditional on.
next prev parent reply other threads:[~2012-06-11 17:22 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-24 11:04 [rfc][patch] select_idle_sibling() inducing bouncing on westmere Mike Galbraith
2012-05-24 13:17 ` Peter Zijlstra
2012-05-24 13:20 ` Peter Zijlstra
2012-05-25 6:14 ` Mike Galbraith
2012-05-26 6:37 ` Mike Galbraith
2012-05-26 7:29 ` Peter Zijlstra
2012-05-26 8:27 ` Mike Galbraith
2012-05-27 9:17 ` Mike Galbraith
2012-05-27 11:02 ` Mike Galbraith
2012-05-27 11:12 ` Mike Galbraith
2012-05-27 14:11 ` Arjan van de Ven
2012-05-27 14:29 ` Mike Galbraith
2012-05-27 14:32 ` Mike Galbraith
2012-05-29 18:58 ` Andreas Herrmann
2012-05-25 6:08 ` Mike Galbraith
2012-05-25 8:06 ` Mike Galbraith
2012-06-05 14:30 ` Mike Galbraith
2012-06-11 16:57 ` [patch v3] sched: fix select_idle_sibling() induced bouncing Mike Galbraith
2012-06-11 17:22 ` Peter Zijlstra [this message]
2012-06-11 17:55 ` Mike Galbraith
2012-06-11 18:53 ` Suresh Siddha
2012-06-12 3:18 ` Mike Galbraith
2012-06-20 10:48 ` [tip:sched/core] sched: Improve scalability via 'CPU buddies', which withstand random perturbations tip-bot for Mike Galbraith
2012-07-24 14:18 ` tip-bot for Mike Galbraith
2012-06-19 8:47 ` [patch v3] sched: fix select_idle_sibling() induced bouncing Paul Turner
2012-06-06 10:17 ` [rfc][patch] select_idle_sibling() inducing bouncing on westmere Mike Galbraith
2012-06-06 10:38 ` Mike Galbraith
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