From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760363AbYEHJNc (ORCPT ); Thu, 8 May 2008 05:13:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755429AbYEHJNY (ORCPT ); Thu, 8 May 2008 05:13:24 -0400 Received: from viefep18-int.chello.at ([213.46.255.22]:3342 "EHLO viefep18-int.chello.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755365AbYEHJNX (ORCPT ); Thu, 8 May 2008 05:13:23 -0400 X-SourceIP: 80.56.237.116 Subject: Re: sysbench+mysql(oltp, readonly) 30% regression with 2.6.26-rc1 From: Peter Zijlstra To: "Zhang, Yanmin" Cc: Mike Galbraith , LKML , Ingo Molnar In-Reply-To: <1210237267.3453.143.camel@ymzhang> References: <1210136148.3453.59.camel@ymzhang> <1210177575.6525.4.camel@lappy.programming.kicks-ass.net> <1210228531.3453.124.camel@ymzhang> <1210233617.4895.6.camel@marge.simson.net> <1210237267.3453.143.camel@ymzhang> Content-Type: text/plain; charset=utf-8 Date: Thu, 08 May 2008 11:13:18 +0200 Message-Id: <1210237998.13978.189.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2008-05-08 at 17:01 +0800, Zhang, Yanmin wrote: > On Thu, 2008-05-08 at 10:00 +0200, Mike Galbraith wrote: > > On Thu, 2008-05-08 at 14:35 +0800, Zhang, Yanmin wrote: > > > On Wed, 2008-05-07 at 18:26 +0200, Peter Zijlstra wrote: > > > > On Wed, 2008-05-07 at 12:55 +0800, Zhang, Yanmin wrote: > > > > > Comparing with kernel 2.6.25, sysbench+mysql(oltp, readonly) has many > > > > > regression with 2.6.26-rc1. > > > > > > > > > > 1) 8-core stoakley: 28%; > > > > > 2) 16-core tigerton: 20%; > > > > > 3) Itanium Montvale: 50%. > > > > > > > > > > Bisect located below patch. > > > > > > > > > > 8f1bc385cfbab474db6c27b5af1e439614f3025c is first bad commit > > > > > commit 8f1bc385cfbab474db6c27b5af1e439614f3025c > > > > > Author: Peter Zijlstra > > > > > Date: Sat Apr 19 19:45:00 2008 +0200 > > > > > > > > > > sched: fair: weight calculations > > > > > > > > > > In order to level the hierarchy, we need to calculate load based on the > > > > > root view. That is, each task's load is in the same unit. > > > > > > > > > > > > > > > > > > > > After I manually reverted the patch against 2.6.26-rc1 while fixing a couple of > > > > > conflictions/errors, sysbench oltp regression became less than 3% on 8-core > > > > > stoakley. > > > > > > > > Does this patch help? > > > With the patch, oltp testing result is about 50% worse than the one of pure > > > 2.6.26-rc1. > > > > Hm. I was doing some sysbench+postgress(oltp, ro) testing on my little > > Q6600 box this morning, and saw a different picture. > How many cpu are in the Q6600? That's an Intel Quad core (Kentsfield). > > In attached pdf, .bkl refers to Linus' BKL patch, .weight is the weight > > fix, both are applied to git.today. The script I used is also attached. > With my 8-core stoakley (using mysql): > 1) 2.6.25: > Number of threads: 6 > read/write requests: 8025024 (66874.53 per sec.) > Number of threads: 8 > read/write requests: 9132816 (76106.14 per sec.) > Number of threads: 10 > read/write requests: 9244998 (77040.75 per sec.) > Number of threads: 12 > read/write requests: 8994174 (74950.36 per sec.) > Number of threads: 14 > read/write requests: 9051322 (75426.54 per sec.) > Number of threads: 16 > read/write requests: 9015412 (75126.93 per sec.) > > 2) 2.6.26-rc1: > Number of threads: 6 > read/write requests: 5754056 (47949.87 per sec.) > Number of threads: 8 > read/write requests: 6528480 (54403.29 per sec.) > Number of threads: 10 > read/write requests: 6444690 (53705.16 per sec.) > Number of threads: 12 > read/write requests: 6544258 (54534.23 per sec.) > Number of threads: 14 > read/write requests: 6796650 (56637.65 per sec.) > Number of threads: 16 > read/write requests: 6718110 (55983.18 per sec.) > > 3) 2.6.26-rc1+weight > Number of threads: 16 > read/write requests: 3219076 (26824.22 per sec.) > > I'm not sure if more cpu could introduce more contention in this test. those numbers make me sad :-(