From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Jie Chen <chen@jlab.org>
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org
Subject: Re: Possible bug from kernel 2.6.22 and above, 2.6.24-rc4
Date: Wed, 12 Dec 2007 13:49:06 +0100 [thread overview]
Message-ID: <1197463746.7042.2.camel@twins> (raw)
In-Reply-To: <475F0B07.2060303@jlab.org>
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On Tue, 2007-12-11 at 17:11 -0500, Jie Chen wrote:
> Ingo Molnar wrote:
> > * Jie Chen <chen@jlab.org> wrote:
> >
> >> The following is pthread_sync output for 2.6.21.7-cfs-v24 #1 SMP
> >> kernel.
> >
> >> 2 threads:
> >
> >> PARALLEL time = 11.106580 microseconds +/- 0.002460
> >> PARALLEL overhead = 0.617590 microseconds +/- 0.003409
> >
> >> Output for Kernel 2.6.24-rc4 #1 SMP
> >
> >> PARALLEL time = 19.668450 microseconds +/- 0.015782
> >> PARALLEL overhead = 9.157945 microseconds +/- 0.018217
> >
> > ok, so the problem is that this PARALLEL time has an additional +9 usecs
> > overhead, right? I dont see this myself on a Core2 CPU:
> >
> > PARALLEL time = 10.446933 microseconds +/- 0.078849
> > PARALLEL overhead = 0.751732 microseconds +/- 0.177446
> >
On my dual socket AMD Athlon MP
2.6.20-13-generic
PARALLEL time = 22.751875 microseconds +/- 21.370942
PARALLEL overhead = 7.046595 microseconds +/- 24.370040
2.6.24-rc5
PARALLEL time = 17.365543 microseconds +/- 3.295133
PARALLEL overhead = 2.213722 microseconds +/- 4.797886
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next prev parent reply other threads:[~2007-12-12 12:49 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-21 20:34 Possible bug from kernel 2.6.22 and above Jie Chen
2007-11-21 22:14 ` Eric Dumazet
2007-11-22 1:52 ` Jie Chen
2007-11-22 2:32 ` Simon Holm Thøgersen
2007-11-22 2:58 ` Jie Chen
2007-11-22 20:19 ` Matt Mackall
2007-12-04 13:17 ` Possible bug from kernel 2.6.22 and above, 2.6.24-rc4 Ingo Molnar
2007-12-04 15:41 ` Jie Chen
2007-12-05 15:29 ` Jie Chen
2007-12-05 15:40 ` Ingo Molnar
2007-12-05 16:16 ` Eric Dumazet
2007-12-05 16:25 ` Ingo Molnar
2007-12-05 16:29 ` Eric Dumazet
2007-12-05 16:22 ` Jie Chen
2007-12-05 16:47 ` Ingo Molnar
2007-12-05 17:47 ` Jie Chen
2007-12-05 20:03 ` Ingo Molnar
2007-12-05 20:23 ` Jie Chen
2007-12-05 20:46 ` Ingo Molnar
2007-12-05 20:52 ` Jie Chen
2007-12-05 21:02 ` Ingo Molnar
2007-12-05 22:16 ` Jie Chen
2007-12-06 10:43 ` Ingo Molnar
2007-12-06 16:29 ` Jie Chen
2007-12-10 10:59 ` Ingo Molnar
2007-12-10 20:04 ` Jie Chen
2007-12-11 10:51 ` Ingo Molnar
2007-12-11 15:28 ` Jie Chen
2007-12-11 15:52 ` Ingo Molnar
2007-12-11 16:39 ` Jie Chen
2007-12-11 21:23 ` Ingo Molnar
2007-12-11 22:11 ` Jie Chen
2007-12-12 12:49 ` Peter Zijlstra [this message]
2007-12-05 20:36 ` Possible bug from kernel 2.6.22 and above Peter Zijlstra
2007-12-05 20:53 ` Jie Chen
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