From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752574AbXLEV25 (ORCPT ); Wed, 5 Dec 2007 16:28:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753903AbXLEV2r (ORCPT ); Wed, 5 Dec 2007 16:28:47 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:57194 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752292AbXLEV2r (ORCPT ); Wed, 5 Dec 2007 16:28:47 -0500 Date: Wed, 5 Dec 2007 13:26:31 -0800 From: Arjan van de Ven To: Holger.Wolf@de.ibm.com Cc: wolf@linux.vnet.ibm.com, mingo@elte.hu, schwidefsky@de.ibm.com, linux-kernel@vger.kernel.org Subject: Re: Scheduler behaviour Message-ID: <20071205132631.79940bd5@laptopd505.fenrus.org> In-Reply-To: <475706E2.50805@linux.vnet.ibm.com> References: <475706E2.50805@linux.vnet.ibm.com> Organization: Intel X-Mailer: Claws Mail 3.0.2 (GTK+ 2.12.1; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 05 Dec 2007 21:15:30 +0100 Holger Wolf wrote: > We discovered performance degradation with dbench when using kernel > 2.6.23 compared to kernel 2.6.22. > > In our case we booted a Linux in a IBM System z9 LPAR with 256MB of > ram with 4 CPU's. This system uses a striped LV with 16 disks on a > Storage Server connected via 8 4GBit links. > A dbench was started on that system performing I/O operations on the > striped LV. dbench runs were performed with 1 to 62 processes. > Measurements with a 2.6.22 kernel were compared to measurements with > a 2.6.23 kernel. We saw a throughput degradation from 7.2 to 23.4 this is good news! dbench rewards unfair behavior... so higher dbench usually means a worse kernel ;) -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org