From: Mike Galbraith <efault@gmx.de>
To: Yinghai Lu <yinghai.lu@oracle.com>
Cc: Greg KH <gregkh@suse.de>, Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
John Wright <john.wright@hp.com>
Subject: Re: 2.6.32.y stable kernel regression with taskset
Date: Thu, 16 Sep 2010 05:45:12 +0200 [thread overview]
Message-ID: <1284608712.7403.10.camel@marge.simson.net> (raw)
In-Reply-To: <4C9114A6.6040500@oracle.com>
On Wed, 2010-09-15 at 11:47 -0700, Yinghai Lu wrote:
> found problem with cpuscaling test.
>
> Under 2.6.32.21 Userspace gov
> min freq load test time is nearly the same as max freq load test time around ~16 seconds
>
> under 2.6.18-194
> min freq load test time is ~40 seconds
> max freq load test time is ~ 17 seconds
>
> the test is
> 1. set governor for one cpu to userspace
> 2. set freq to min for that cpu
> 3. using taskset to put load test only on that cpu, and get the time for load test.
>
> so that mean taskset did not put load test on cpu that we want. and other cpu still have ondemand governor and load test get done much faster
>
> git bisect report:
>
> c6fc81afa2d7ef2f775e48672693d8a0a8a7325d is the first bad commit
> commit c6fc81afa2d7ef2f775e48672693d8a0a8a7325d
> Author: John Wright <john.wright@hp.com>
> Date: Tue Apr 13 16:55:37 2010 -0600
>
> sched: Fix a race between ttwu() and migrate_task()
Known issue. There's a sched series for 32-stable in the pipeline.
-Mike
next prev parent reply other threads:[~2010-09-16 3:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-15 18:47 Yinghai Lu
2010-09-16 3:45 ` Mike Galbraith [this message]
2010-09-16 14:42 ` Greg KH
2010-09-16 19:35 ` Yinghai Lu
2010-09-17 4:46 ` Mike Galbraith
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