From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261965AbTKYFBe (ORCPT ); Tue, 25 Nov 2003 00:01:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261967AbTKYFBe (ORCPT ); Tue, 25 Nov 2003 00:01:34 -0500 Received: from [64.65.189.210] ([64.65.189.210]:58084 "EHLO mail.pacrimopen.com") by vger.kernel.org with ESMTP id S261965AbTKYFBc (ORCPT ); Tue, 25 Nov 2003 00:01:32 -0500 Subject: Re: RAID-0 read perf. decrease after 2.4.20 From: Joshua Schmidlkofer To: Linux Kernel Mailing List In-Reply-To: <20031124100534.24941.qmail@web13902.mail.yahoo.com> References: <20031124100534.24941.qmail@web13902.mail.yahoo.com> Content-Type: text/plain Message-Id: <1069736477.1552.11.camel@menion.home> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.5 Date: Mon, 24 Nov 2003 21:01:18 -0800 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2003-11-24 at 02:05, Martin Knoblauch wrote: > >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 > > And this isn't the read-ahead size change thing?