linux-kernel - Re: [Bugme-new] [Bug 12562] New: High overhead while switching or synchronizing threads on different cores

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Message-ID: <51126.1233633409@turing-police.cc.vt.edu>
Date:	Mon, 02 Feb 2009 22:56:49 -0500
From:	Valdis.Kletnieks@...edu
To:	Thomas Pilarski <thomas.pi@...or.de>
Cc:	Mike Galbraith <efault@....de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Gregory Haskins <ghaskins@...ell.com>,
	bugme-daemon@...zilla.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [Bugme-new] [Bug 12562] New: High overhead while switching or synchronizing threads on different cores

On Mon, 02 Feb 2009 08:43:55 +0100, Thomas Pilarski said:
> Am Freitag, den 30.01.2009, 08:57 +0100 schrieb Mike Galbraith:
> > One of those "don't _ever_ do that" things?
> 
> I did not known random() uses a system call. It's rather unrealistic to
> have five million system calls in a second. By adding a small loop with
> some calculations near the random, the problem disappears too.
> It is a unlucky chosen data generator.

Am I the only one that's scared by the concept of anything that beats
on random numbers enough to need 5 million of them a second, but is still
using the relatively sucky one that's in most glibc's? :) 


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