From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752772AbXLFKoh (ORCPT ); Thu, 6 Dec 2007 05:44:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751879AbXLFKo3 (ORCPT ); Thu, 6 Dec 2007 05:44:29 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:46404 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751739AbXLFKo2 (ORCPT ); Thu, 6 Dec 2007 05:44:28 -0500 Date: Thu, 6 Dec 2007 11:43:18 +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: <20071206104318.GB30838@elte.hu> References: <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> <20071205210222.GA30089@elte.hu> <47572353.4040606@jlab.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47572353.4040606@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: >> 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 > > Hi, Ingo: > > Did you do configure --enable-public-release? My qmt is for qcd > calculation (one type of physics code) [...] yes, i did exactly as instructed. > [...]. Without the above flag one can only test PARALLEL overhead. > Actually the PARALLEL benchmark has the same behavior as the BARRIER. > Thanks. hm, but PARALLEL does not seem to do that much context switching. So basically you create the threads and do a few short runs to establish overhead? Threads do not get fork-balanced at the moment - but turning it on would be easy. Could you try the patch below - how does it impact your results? (and please keep affinity setting off) Ingo -----------> Subject: sched: reactivate fork balancing From: Ingo Molnar reactivate fork balancing. Signed-off-by: Ingo Molnar --- include/linux/topology.h | 3 +++ 1 file changed, 3 insertions(+) Index: linux/include/linux/topology.h =================================================================== --- linux.orig/include/linux/topology.h +++ linux/include/linux/topology.h @@ -103,6 +103,7 @@ .forkexec_idx = 0, \ .flags = SD_LOAD_BALANCE \ | SD_BALANCE_NEWIDLE \ + | SD_BALANCE_FORK \ | SD_BALANCE_EXEC \ | SD_WAKE_AFFINE \ | SD_WAKE_IDLE \ @@ -134,6 +135,7 @@ .forkexec_idx = 1, \ .flags = SD_LOAD_BALANCE \ | SD_BALANCE_NEWIDLE \ + | SD_BALANCE_FORK \ | SD_BALANCE_EXEC \ | SD_WAKE_AFFINE \ | SD_WAKE_IDLE \ @@ -165,6 +167,7 @@ .forkexec_idx = 1, \ .flags = SD_LOAD_BALANCE \ | SD_BALANCE_NEWIDLE \ + | SD_BALANCE_FORK \ | SD_BALANCE_EXEC \ | SD_WAKE_AFFINE \ | BALANCE_FOR_PKG_POWER,\