Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753450AbXLEVCz (ORCPT ); Wed, 5 Dec 2007 16:02:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751644AbXLEVCs (ORCPT ); Wed, 5 Dec 2007 16:02:48 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:48926 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751564AbXLEVCr (ORCPT ); Wed, 5 Dec 2007 16:02:47 -0500 Date: Wed, 5 Dec 2007 22:02:22 +0100 From: Ingo Molnar To: Jie Chen Cc: Simon Holm Th??gersen , Eric Dumazet , linux-kernel@vger.kernel.org, Peter Zijlstra Subject: Re: Possible bug from kernel 2.6.22 and above, 2.6.24-rc4 Message-ID: <20071205210222.GA30089@elte.hu> References: <20071204131707.GA4232@elte.hu> <4756C3D9.9030107@jlab.org> <20071205154014.GA6491@elte.hu> <4756D058.1070500@jlab.org> <20071205164723.GA25641@elte.hu> <4756E44E.8080607@jlab.org> <20071205200343.GA14570@elte.hu> <475708A7.4030708@jlab.org> <20071205204645.GC25694@elte.hu> <47570F83.6040601@jlab.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47570F83.6040601@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 Content-Length: 1506 Lines: 35 * Jie Chen wrote: >> sorry to be dense, but could you give me instructions how i could >> remove the affinity mask and test the "barrier overhead" myself? I >> have built "pthread_sync" and it outputs numbers for me - which one >> would be the barrier overhead: Reference_time_1 ? > > To disable affinity, do configure --enable-public-release > --disable-thread_affinity. You should see barrier overhead like the > following: Computing BARRIER time > > Sample_size Average Min Max S.D. Outliers > 20 19.486162 19.482250 19.491400 0.002740 0 > > BARRIER time = 19.486162 microseconds +/- 0.005371 > BARRIER overhead = 8.996257 microseconds +/- 0.006575 ok, i did that and rebuilt. I also did "make check" and got src/pthread_sync which i can run. The only thing i'm missing, if i run src/pthread_sync, it outputs "PARALLEL time": PARALLEL time = 22.486103 microseconds +/- 3.944821 PARALLEL overhead = 10.638658 microseconds +/- 10.854154 not "BARRIER time". I've re-read the discussion and found no hint about how to build and run a barrier test. Either i missed it or it's so obvious to you that you didnt mention it :-) Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/