From: Mike Galbraith <efault@gmx.de>
To: Olof Johansson <olof@lixom.net>
Cc: Willy Tarreau <w@1wt.eu>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: Scheduler(?) regression from 2.6.22 to 2.6.24 for short-lived threads
Date: Wed, 13 Feb 2008 06:49:22 +0100 [thread overview]
Message-ID: <1202881762.27877.5.camel@homer.simson.net> (raw)
In-Reply-To: <1202808206.7829.36.camel@homer.simson.net>
On Tue, 2008-02-12 at 10:23 +0100, Mike Galbraith wrote:
> If you plunk a usleep(1) in prior to calling thread_func() does your
> testcase performance change radically? If so, I wonder if the real
> application has the same kind of dependency.
The answer is yes for 2.6.22, and no for 2.6.24, which surprised me.
2.6.22.17-smp
homer:..local/tmp # ./threadtest2
10000000 loops time 16215 ms
10000000 loops time 16268 ms
10000000 loops time 16246 ms
homer:..local/tmp # ./threadtest3 (with usleep(1))
10000000 loops time 13938 ms
10000000 loops time 13921 ms
10000000 loops time 13898 ms
2.6.24.1-smp
homer:..local/tmp # ./threadtest2
10000000 loops time 14663 ms
10000000 loops time 14523 ms
10000000 loops time 14466 ms
homer:..local/tmp # ./threadtest3
10000000 loops time 14513 ms
10000000 loops time 14500 ms
10000000 loops time 14464 ms
echo 0 > /proc/sys/kernel/sched_child_runs_first
homer:..local/tmp # ./threadtest2
10000000 loops time 14157 ms
10000000 loops time 14097 ms
10000000 loops time 14153 ms
homer:..local/tmp # ./threadtest3
10000000 loops time 14065 ms
10000000 loops time 14075 ms
10000000 loops time 14018 ms
next prev parent reply other threads:[~2008-02-13 5:49 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-09 0:04 Olof Johansson
2008-02-09 0:08 ` Ingo Molnar
2008-02-09 0:32 ` Olof Johansson
2008-02-09 7:58 ` Mike Galbraith
2008-02-09 8:03 ` Willy Tarreau
2008-02-09 10:58 ` Mike Galbraith
2008-02-09 11:40 ` Willy Tarreau
2008-02-09 13:37 ` Mike Galbraith
2008-02-09 16:19 ` Willy Tarreau
2008-02-09 17:33 ` Mike Galbraith
2008-02-10 5:29 ` Olof Johansson
2008-02-10 6:15 ` Willy Tarreau
2008-02-10 7:00 ` Olof Johansson
2008-02-10 7:58 ` Willy Tarreau
2008-02-11 8:15 ` Mike Galbraith
2008-02-11 17:26 ` Olof Johansson
2008-02-11 19:58 ` Mike Galbraith
2008-02-11 20:31 ` Olof Johansson
2008-02-12 9:23 ` Mike Galbraith
2008-02-13 5:49 ` Mike Galbraith [this message]
2008-02-11 21:45 ` Bill Davidsen
2008-02-12 4:30 ` Mike Galbraith
[not found] <fa.6N2dhyJ1cmBqiuFKgCaYfwduM+0@ifi.uio.no>
2008-02-09 1:49 ` Robert Hancock
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