From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752495AbYAPQUY (ORCPT ); Wed, 16 Jan 2008 11:20:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751823AbYAPQUI (ORCPT ); Wed, 16 Jan 2008 11:20:08 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:36222 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751328AbYAPQUG (ORCPT ); Wed, 16 Jan 2008 11:20:06 -0500 Date: Wed, 16 Jan 2008 17:19:51 +0100 From: Ingo Molnar To: Colin Fowler Cc: linux-kernel@vger.kernel.org, Peter Zijlstra Subject: Re: Performance loss 2.6.22->22.6.23->2.6.24-rc7 on CPU intensive benchmark on 8 Core Xeon Message-ID: <20080116161951.GA15000@elte.hu> References: <20080114185520.GA26540@elte.hu> <20080115220641.GC2665@elte.hu> <20080116153505.GB18553@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 * Colin Fowler wrote: > Hi Ingo, I'll need to convince my supervisor first if I can release a > binary. Technically anythin glike this needs to go through our > University's "innovations department" and requires lengthy paperwork > and NDAs :(. a binary wouldnt work for me anyway. But you could try to write a "workload simulator": just pick out the pthread ops and replace the worker functions with some dummy stuff that just touches an array that has similar size to the tiles (in a tight loop). Make sure it has similar context-switch rate and idle percentage as your real workload - then send us the .c file. As long as it's a single .c file that runs for a few seconds and outputs a precise enough "run time" result, kernel developers would pick it up and use it for optimizations. To get the # of cpus automatically you can do: cpus = system("exit `grep processor /proc/cpuinfo | wc -l`"); cpus = WEXITSTATUS(cpus); and start as many threads as many CPUs there are in the system. Ingo