From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752666AbXCNBAv (ORCPT ); Tue, 13 Mar 2007 21:00:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752675AbXCNBAv (ORCPT ); Tue, 13 Mar 2007 21:00:51 -0400 Received: from gw1.cosmosbay.com ([86.65.150.130]:42715 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752666AbXCNBAv (ORCPT ); Tue, 13 Mar 2007 21:00:51 -0400 Message-ID: <45F74917.40806@cosmosbay.com> Date: Wed, 14 Mar 2007 02:00:07 +0100 From: Eric Dumazet User-Agent: Thunderbird 1.5.0.10 (Windows/20070221) MIME-Version: 1.0 To: Nish Aravamudan CC: Anton Blanchard , Nick Piggin , Rik van Riel , Lorenzo Allegrucci , linux-kernel@vger.kernel.org, Ingo Molnar , Suparna Bhattacharya , Jens Axboe Subject: Re: SMP performance degradation with sysbench References: <1172425476.5489.11.camel@odyssey.lan> <45E21FEC.9060605@redhat.com> <45E2E244.8040009@yahoo.com.au> <20070312220042.GA807@kryten> <29495f1d0703131736l74a63c15n94f03527d7e63500@mail.gmail.com> In-Reply-To: <29495f1d0703131736l74a63c15n94f03527d7e63500@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-1.6 (gw1.cosmosbay.com [86.65.150.130]); Wed, 14 Mar 2007 02:00:13 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nish Aravamudan a écrit : > On 3/12/07, Anton Blanchard wrote: >> >> Hi Nick, >> >> > Anyway, I'll keep experimenting. If anyone from MySQL wants to help >> look >> > at this, send me a mail (eg. especially with the sched_setscheduler >> issue, >> > you might be able to do something better). >> >> I took a look at this today and figured Id document it: >> >> http://ozlabs.org/~anton/linux/sysbench/ >> >> Bottom line: it looks like issues in the glibc malloc library, replacing >> it with the google malloc library fixes the negative scaling: >> >> # apt-get install libgoogle-perftools0 >> # LD_PRELOAD=/usr/lib/libtcmalloc.so /usr/sbin/mysqld > > Quick datapoint, still collecting data and trying to verify it's > always the case: on my 8-way Xeon, I'm actually seeing *much* worse > performance with libtcmalloc.so compared to mainline. Am generating > graphs and such still, but maybe someone else with x86_64 hardware > could try the google PRELOAD and see if it helps/hurts (to rule out > tester stupidity)? I wish I had a 8-way test platform :) Anyway, could you post some oprofile results ?