From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263715AbTKXKFt (ORCPT ); Mon, 24 Nov 2003 05:05:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263726AbTKXKFt (ORCPT ); Mon, 24 Nov 2003 05:05:49 -0500 Received: from web13902.mail.yahoo.com ([216.136.175.28]:65077 "HELO web13902.mail.yahoo.com") by vger.kernel.org with SMTP id S263715AbTKXKFh (ORCPT ); Mon, 24 Nov 2003 05:05:37 -0500 Message-ID: <20031124100534.24941.qmail@web13902.mail.yahoo.com> X-RocketYMMF: knobi.rm Date: Mon, 24 Nov 2003 02:05:34 -0800 (PST) From: Martin Knoblauch Reply-To: knobi@knobisoft.de Subject: Re: RAID-0 read perf. decrease after 2.4.20 To: linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >Hello All! > >Has anyone else experienced a drastic drop in read performance on >software >RAID-0 with post 2.4.20 kernels? We have a few Athlon XP's here at our >lab with double IDE disks on different channels set up as RAID-0. Some >bonnie++ benchmark results with various kernels, on the same machine >(Athlon XP 2400+, 2 GHz, 1.5 GB RAM, VIA chipset, 2*Maxtor 120 GB >6Y060L0): >write read >2.4.20-ac1: 88,000 135,000 K/sec >2.4.21-pre7: 93,000 75,000 >2.4.22-ac4: 94,000 82,000 Hi, I can attest a similar drop in read performance on a IA64 box going from a 2.4.19ish kernel to 2.4.22. In our setup the RAID0 is LVM, not MD.The RAID is used a a scratch device for a out-of-core finite element program (NASTRAN). The setup is some 20 disks on 4 controllers. "iozone" read/reread Performance went from about 400MB/sec to 260 MB/sec, while write went up a notch. Unfortunatelly the read performance is more important for the application in question. Due to the fact that I have no controll over the use of the system I cannot make any experiments to find out what killed performance. Sorry :-( Martin ===== ------------------------------------------------------ Martin Knoblauch email: knobi@knobisoft.de or knobi@rocketmail.com www: http://www.knobisoft.de