From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262076AbTKTQpX (ORCPT ); Thu, 20 Nov 2003 11:45:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262078AbTKTQpW (ORCPT ); Thu, 20 Nov 2003 11:45:22 -0500 Received: from mail.it.helsinki.fi ([128.214.205.39]:46467 "EHLO mail.it.helsinki.fi") by vger.kernel.org with ESMTP id S262076AbTKTQpQ (ORCPT ); Thu, 20 Nov 2003 11:45:16 -0500 Date: Thu, 20 Nov 2003 18:45:13 +0200 (EET) From: Mikael Johansson X-X-Sender: mpjohans@soul.helsinki.fi To: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: RAID-0 read perf. decrease after 2.4.20 Message-ID: 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 So the write speed has gone up a bit, but the read speed performance has plunged. Any ideas on what happened between 2.4.20 and 2.4.21 and what to do about it? I'm eagerly awaiting suggestions, good read speed is quite critical for many of our calculations :-) I will of course provide more details if necessary. Have a nice day, Mikael J. http://www.helsinki.fi/~mpjohans/