From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755158AbXLKPw4 (ORCPT ); Tue, 11 Dec 2007 10:52:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754323AbXLKPwk (ORCPT ); Tue, 11 Dec 2007 10:52:40 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:59081 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754186AbXLKPwi (ORCPT ); Tue, 11 Dec 2007 10:52:38 -0500 Date: Tue, 11 Dec 2007 16:52:26 +0100 From: Ingo Molnar To: Jie Chen Cc: linux-kernel@vger.kernel.org, Peter Zijlstra Subject: Re: Possible bug from kernel 2.6.22 and above, 2.6.24-rc4 Message-ID: <20071211155226.GA1056@elte.hu> References: <20071205204645.GC25694@elte.hu> <47570F83.6040601@jlab.org> <20071205210222.GA30089@elte.hu> <47572353.4040606@jlab.org> <20071206104318.GB30838@elte.hu> <47582367.6060602@jlab.org> <20071210105943.GA5370@elte.hu> <475D9BB5.20808@jlab.org> <20071211105149.GA24250@elte.hu> <475EAC81.1020408@jlab.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <475EAC81.1020408@jlab.org> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jie Chen wrote: > Hi, Ingo: > > I guess it is a good news. I did patch 2.6.21.7 kernel using your cfs > patch. The results of pthread_sync is the same as the non-patched > 2.6.21 kernel. This means the performance of is not related to the > scheduler. As for overhead of the gettimeofday, there is no difference > between 2.6.21 and 2.6.24-rc4. The reference time is around 10.5 us > for both kernel. could you please paste again the relevant portion of the output you get on a "good" .21 kernel versus the output you get on a "bad" .24 kernel? > So what is changed between 2.6.21 and 2.6.22? Any hints :-). Thank you > very much for all your help. we'll figure it out i'm sure :) Ingo