From: Jens Axboe Subject: Re: Performance degradation with FFSB between 2.6.20 and 2.6.21-rc7 Date: Thu, 19 Apr 2007 14:46:30 +0200 Message-ID: <20070419124630.GD11780@kernel.dk> References: <462622F8.10107@bull.net> <20070419090346.GE20928@kernel.dk> <462736FC.3090902@bull.net> <20070419115840.GA11780@kernel.dk> <4627644E.7010002@bull.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: ext4 development , Andrew Morton , Linux Kernel Mailing List To: Valerie Clement Return-path: Received: from brick.kernel.dk ([80.160.20.94]:1754 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031239AbXDSMtA (ORCPT ); Thu, 19 Apr 2007 08:49:00 -0400 Content-Disposition: inline In-Reply-To: <4627644E.7010002@bull.net> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, Apr 19 2007, Valerie Clement wrote: > Jens Axboe wrote: > >On Thu, Apr 19 2007, Valerie Clement wrote: > >>Jens Axboe wrote: > >>>Please tell me how you are running ffsb, and also please include a > >>>dmessg from a booted system. > >>> > >>Hi, > >>our mails crossed! please see my response to Andrew. > >>You could reproduce the problem with dd command as suggested, it's more > >>easy. > >>I'm sending you the dmesg info. For my tests I used the scsci sdc device. > > > >Thanks, it does. Can you try one thing for me? If you run the test on > >sdc, try doing: > > > ># echo 64 > /sys/block/sdc/queue/iosched/quantum > > > >and repeat the test. > > > > OK, that's done. > > With the change of quantum, the throughput scores are now a little bit > better in 2.6.21 than in 2.6.20. Wonderful, now try the patch I sent in the next mail and repeat the test. -- Jens Axboe