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From: Ingo Molnar <mingo@elte.hu>
To: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Suresh Siddha <suresh.b.siddha@intel.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Paul Turner <pjt@google.com>
Subject: Re: sched: Avoid SMT siblings in select_idle_sibling() if possible
Date: Thu, 23 Feb 2012 12:26:50 +0100	[thread overview]
Message-ID: <20120223112650.GA23844@elte.hu> (raw)
In-Reply-To: <20120223112005.GA7645@linux.vnet.ibm.com>


* Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:

> "perf bench sched pipe" was run 10 times and average ops/sec 
> score alongwith std. dev is noted as below.
> 
> 
> 		SD_BALANCE_WAKE		SD_BALANCE_WAKE
> 		 disabled		enabled
> 
> Avg. score	108984.900 		111844.300 (+2.6%)
> std dev		20383.457		21668.604

pro perf tip of the day: did you know that it's possible to run:

  perf stat --repeat 10 --null perf bench sched pipe

and get meaningful, normalized stddev calculations for free:

       5.486491487 seconds time elapsed                                          ( +-  5.50% )

the percentage at the end shows the level of standard deviation.

You can add "--sync" as well, which will cause perf stat to call 
sync() - this gives extra stability of individual iterations and 
makes sure all IO cost is accounted to the right run.

Thanks,

	Ingo

  reply	other threads:[~2012-02-23 11:26 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-15  9:46 sched: Avoid SMT siblings in select_idle_sibling() if possible Peter Zijlstra
2011-11-16  1:14 ` Suresh Siddha
2011-11-16  9:24   ` Mike Galbraith
2011-11-16 18:37     ` Suresh Siddha
2011-11-17  1:59       ` Mike Galbraith
2011-11-17 15:38         ` Mike Galbraith
2011-11-17 15:56           ` Peter Zijlstra
2011-11-17 16:38             ` Mike Galbraith
2011-11-17 17:36               ` Suresh Siddha
2011-11-18 15:14                 ` Mike Galbraith
2011-11-18 15:17                   ` [patch 1/6] sched: use rt.nr_cpus_allowed to recover select_task_rq() cycles Mike Galbraith
2011-11-18 15:35                     ` Peter Zijlstra
2011-11-18 17:34                       ` Mike Galbraith
2011-11-22 14:17                       ` Mike Galbraith
2011-11-22 14:18                         ` [patch 1/7] " Mike Galbraith
2011-12-06  9:50                           ` [tip:sched/core] sched: Use " tip-bot for Mike Galbraith
2011-11-22 14:20                         ` [patch 2/7] sched: save some hrtick_start_fair cycles Mike Galbraith
2011-12-06 20:20                           ` [tip:sched/core] sched: Save " tip-bot for Mike Galbraith
2011-11-22 14:21                         ` [patch 3/7] sched: set skip_clock_update in yield_task_fair() Mike Galbraith
2011-11-23 11:53                           ` Peter Zijlstra
2011-11-23 12:06                             ` Mike Galbraith
2011-11-23 14:48                           ` Peter Zijlstra
2011-11-24  3:50                             ` Mike Galbraith
2011-11-24 10:12                               ` Peter Zijlstra
2011-11-25  6:39                                 ` Mike Galbraith
2011-12-06  9:51                           ` [tip:sched/core] sched: Set " tip-bot for Mike Galbraith
2011-11-22 14:22                         ` [patch 4/7] sched: convert rq->avg_idle to rq->avg_event Mike Galbraith
2011-11-23 11:55                           ` Peter Zijlstra
2011-11-23 12:09                             ` Mike Galbraith
2011-11-23 12:27                               ` Peter Zijlstra
2011-11-23 12:57                                 ` Mike Galbraith
2011-11-23 14:21                                   ` Mike Galbraith
2011-11-22 14:23                         ` [patch 5/7] sched: ratelimit select_idle_sibling()for sync wakeups Mike Galbraith
2011-11-22 14:24                         ` [patch 6/7] sched: use rq->avg_event to resurrect nohz ratelimiting Mike Galbraith
2011-11-23 11:57                           ` Peter Zijlstra
2011-11-23 12:35                           ` Mike Galbraith
2011-11-22 14:26                         ` [patch 7/7] sched: only use TTWU_QUEUE when waker/wakee CPUs do not share top level cache Mike Galbraith
2011-11-23 12:08                           ` Peter Zijlstra
2011-11-18 15:39                     ` [patch 1/6] sched: use rt.nr_cpus_allowed to recover select_task_rq() cycles Hillf Danton
2011-11-18 15:18                   ` [patch 2/6] sched: convert rq->avg_idle to rq->avg_event Mike Galbraith
2011-11-18 15:19                   ` [patch 3/6] sched: use rq->avg_event to resurrect nohz ratelimiting Mike Galbraith
2011-11-18 15:36                     ` Peter Zijlstra
2011-11-18 17:42                       ` Mike Galbraith
2011-11-19  0:51                         ` Van De Ven, Arjan
2011-11-19  4:15                           ` Mike Galbraith
2011-11-18 15:20                   ` [patch 4/6] sched: ratelimit select_idle_sibling()for sync wakeups Mike Galbraith
2011-11-18 15:22                   ` [patch 5/6] sched: save some hrtick_start_fair cycles Mike Galbraith
2011-11-18 15:23                   ` [patch 6/6] sched: set skip_clock_update in yield_task_fair() Mike Galbraith
2012-02-20 14:41                   ` sched: Avoid SMT siblings in select_idle_sibling() if possible Peter Zijlstra
2012-02-20 15:03                     ` Srivatsa Vaddagiri
2012-02-20 18:25                       ` Mike Galbraith
2012-02-21  0:06                         ` Srivatsa Vaddagiri
2012-02-21  6:37                           ` Mike Galbraith
2012-02-21  8:09                             ` Srivatsa Vaddagiri
2012-02-20 18:14                     ` Mike Galbraith
2012-02-20 18:15                       ` Peter Zijlstra
2012-02-20 19:07                       ` Peter Zijlstra
2012-02-21  5:43                         ` Mike Galbraith
2012-02-21  8:32                           ` Srivatsa Vaddagiri
2012-02-21  9:21                             ` Mike Galbraith
2012-02-21 10:37                               ` Peter Zijlstra
2012-02-21 14:58                                 ` Srivatsa Vaddagiri
2012-02-23 10:49                       ` Srivatsa Vaddagiri
2012-02-23 11:19                         ` Ingo Molnar
2012-02-23 12:18                           ` Srivatsa Vaddagiri
2012-02-23 11:20                         ` Srivatsa Vaddagiri
2012-02-23 11:26                           ` Ingo Molnar [this message]
2012-02-23 11:32                             ` Srivatsa Vaddagiri
2012-02-23 16:17                               ` Ingo Molnar
2012-02-23 11:21                         ` Mike Galbraith
2012-02-25  6:54                           ` Srivatsa Vaddagiri
2012-02-25  8:30                             ` Mike Galbraith
2012-02-27 22:11                               ` Suresh Siddha
2012-02-28  5:05                                 ` Mike Galbraith
2011-11-17 19:08             ` Suresh Siddha
2011-11-18 15:12               ` Peter Zijlstra
2011-11-18 15:26                 ` Mike Galbraith
2011-12-06  9:49               ` [tip:sched/core] sched: Clean up domain traversal in select_idle_sibling() tip-bot for Suresh Siddha
2011-11-18 23:40 ` [tip:sched/core] sched: Avoid SMT siblings in select_idle_sibling() if possible tip-bot for Peter Zijlstra
     [not found] <1329764866.2293.376.camhel@twins>
2012-03-05 15:24 ` Srivatsa Vaddagiri
2012-03-06  9:14   ` Ingo Molnar
2012-03-06 10:03     ` Srivatsa Vaddagiri
2012-03-22 15:32     ` Srivatsa Vaddagiri
2012-03-23  6:38       ` Mike Galbraith
2012-03-26  8:29       ` Peter Zijlstra
2012-03-26  8:36       ` Peter Zijlstra
2012-03-26 17:35         ` Srivatsa Vaddagiri
2012-03-26 18:06           ` Peter Zijlstra
2012-03-27 13:56             ` Mike Galbraith

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