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From: Mike Galbraith <mgalbraith@suse.de>
To: Chris Mason <clm@fb.com>, Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Matt Fleming <matt@codeblueprint.co.uk>,
	linux-kernel@vger.kernel.org
Subject: Re: sched: tweak select_idle_sibling to look for idle threads
Date: Sun, 10 Apr 2016 12:04:21 +0200	[thread overview]
Message-ID: <1460282661.4251.44.camel@suse.de> (raw)
In-Reply-To: <20160409190554.honue3gtian2p6vr@floor.thefacebook.com>

On Sat, 2016-04-09 at 15:05 -0400, Chris Mason wrote:

> This does preserve the existing logic to prefer idle cores over idle
> CPU threads, and includes some tests to try and avoid the idle scan when we're
> actually better off sharing a non-idle CPU with someone else.

My box says the "oh nevermind" checks aren't selective enough, tbench
dropped 4% at clients=cores, and 2% at clients=threads.

> Benchmarks in production show overall capacity going up between 2-5%
> depending on the metric.

Latency rules all loads certainly exist, and clearly want some love,
but the bigger the socket, and the more threads/core, the more that
traverse is gonna hurt the others, so seems either we need a better
filter, or a (yeah yeah, yet another damn) tweakable.

Oh, and bounce_to_target() seems an odd way to say full_traverse.

	-Mike

  reply	other threads:[~2016-04-10 10:04 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-05 18:08 [PATCH RFC] select_idle_sibling experiments Chris Mason
2016-04-05 18:43 ` Bastien Bastien Philbert
2016-04-05 19:28   ` Chris Mason
2016-04-05 20:03 ` Matt Fleming
2016-04-05 21:05   ` Bastien Philbert
2016-04-06  0:44   ` Chris Mason
2016-04-06  7:27 ` Mike Galbraith
2016-04-06 13:36   ` Chris Mason
2016-04-09 17:30   ` Chris Mason
2016-04-12 21:45     ` Matt Fleming
2016-04-13  3:40       ` Mike Galbraith
2016-04-13 15:54         ` Chris Mason
2016-04-28 12:00   ` Peter Zijlstra
2016-04-28 13:17     ` Mike Galbraith
2016-05-02  5:35     ` Mike Galbraith
2016-04-07 15:17 ` Chris Mason
2016-04-09 19:05 ` sched: tweak select_idle_sibling to look for idle threads Chris Mason
2016-04-10 10:04   ` Mike Galbraith [this message]
2016-04-10 12:35     ` Chris Mason
2016-04-10 12:46       ` Mike Galbraith
2016-04-10 19:55     ` Chris Mason
2016-04-11  4:54       ` Mike Galbraith
2016-04-12  0:30         ` Chris Mason
2016-04-12  4:44           ` Mike Galbraith
2016-04-12 13:27             ` Chris Mason
2016-04-12 18:16               ` Mike Galbraith
2016-04-12 20:07                 ` Chris Mason
2016-04-13  3:18                   ` Mike Galbraith
2016-04-13 13:44                     ` Chris Mason
2016-04-13 14:22                       ` Mike Galbraith
2016-04-13 14:36                         ` Chris Mason
2016-04-13 15:05                           ` Mike Galbraith
2016-04-13 15:34                             ` Mike Galbraith
2016-04-30 12:47   ` Peter Zijlstra
2016-05-01  7:12     ` Mike Galbraith
2016-05-01  8:53       ` Peter Zijlstra
2016-05-01  9:20         ` Mike Galbraith
2016-05-07  1:24           ` Yuyang Du
2016-05-08  8:08             ` Mike Galbraith
2016-05-08 18:57               ` Yuyang Du
2016-05-09  3:45                 ` Mike Galbraith
2016-05-08 20:22                   ` Yuyang Du
2016-05-09  7:44                     ` Mike Galbraith
2016-05-09  1:13                       ` Yuyang Du
2016-05-09  9:39                         ` Mike Galbraith
2016-05-09 23:26                           ` Yuyang Du
2016-05-10  7:49                             ` Mike Galbraith
2016-05-10 15:26                               ` Mike Galbraith
2016-05-10 19:16                                 ` Yuyang Du
2016-05-11  4:17                                   ` Mike Galbraith
2016-05-11  1:23                                     ` Yuyang Du
2016-05-11  9:56                                       ` Mike Galbraith
2016-05-18  6:41                                   ` Mike Galbraith
2016-05-09  3:52                 ` Mike Galbraith
2016-05-08 20:31                   ` Yuyang Du
2016-05-02  8:46       ` Peter Zijlstra
2016-05-02 14:50         ` Mike Galbraith
2016-05-02 14:58           ` Peter Zijlstra
2016-05-02 15:47             ` Chris Mason
2016-05-03 14:32               ` Peter Zijlstra
2016-05-03 15:11                 ` Chris Mason
2016-05-04 10:37                   ` Peter Zijlstra
2016-05-04 15:31                     ` Peter Zijlstra
2016-05-05 22:03                     ` Matt Fleming
2016-05-06 18:54                       ` Mike Galbraith
2016-05-09  8:33                         ` Peter Zijlstra
2016-05-09  8:56                           ` Mike Galbraith
2016-05-04 15:45                   ` Peter Zijlstra
2016-05-04 17:46                     ` Chris Mason
2016-05-05  9:33                       ` Peter Zijlstra
2016-05-05 13:58                         ` Chris Mason
2016-05-06  7:12                           ` Peter Zijlstra
2016-05-06 17:27                             ` Chris Mason
2016-05-06  7:25                   ` Peter Zijlstra
2016-05-02 17:30             ` Mike Galbraith
2016-05-02 15:01           ` Peter Zijlstra
2016-05-02 16:04             ` Ingo Molnar
2016-05-03 11:31               ` Peter Zijlstra
2016-05-03 18:22                 ` Peter Zijlstra
2016-05-02 15:10           ` Peter Zijlstra

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