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From: Ulrich Drepper <drepper@redhat.com>
To: Pierre Peiffer <pierre.peiffer@bull.net>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@osdl.org>, Jakub Jelinek <jakub@redhat.com>
Subject: Re: [PATCH 2.6.20-rc4 0/4] futexes functionalities and improvements
Date: Tue, 16 Jan 2007 07:14:39 -0800	[thread overview]
Message-ID: <45ACEBDF.60602@redhat.com> (raw)
In-Reply-To: <45AC8E2A.3060708@bull.net>

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Pierre Peiffer wrote:
> I've run this bench 1000 times with pipe and 800 groups.
> Here are the results:

This is not what I'm mostly concerned about.  The patches create a
bottleneck since _all_ processes use the same resource.  Plus, this code
has to be run on a machine with multiple processors to get RFOs into play.

So, please do this: on an SMP (4p or more) machine, rig the test so that
it runs quite a while.  Then, in a script, start the program a bunch of
times, all in parallel.  Have the script wait until all program runs are
done and time the time until the last program finishes.

-- 
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖


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  parent reply	other threads:[~2007-01-16 15:15 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-09 16:15 Pierre Peiffer
2007-01-11 17:47 ` Ulrich Drepper
     [not found]   ` <20070111134615.34902742.akpm@osdl.org>
2007-01-12  7:53     ` Pierre Peiffer
2007-01-12  7:58       ` Ingo Molnar
2007-01-16  8:34         ` Pierre Peiffer
2007-01-16  9:44           ` Ingo Molnar
2007-01-16 15:14           ` Ulrich Drepper [this message]
2007-01-16 15:40             ` Ingo Molnar
2007-01-16 17:46               ` Ulrich Drepper
2007-01-16 17:50                 ` Ingo Molnar
2007-01-17  7:50                   ` Pierre Peiffer

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