Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757558AbZKJSh1 (ORCPT ); Tue, 10 Nov 2009 13:37:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752846AbZKJSh0 (ORCPT ); Tue, 10 Nov 2009 13:37:26 -0500 Received: from cantor2.suse.de ([195.135.220.15]:53059 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752535AbZKJSh0 (ORCPT ); Tue, 10 Nov 2009 13:37:26 -0500 Date: Tue, 10 Nov 2009 19:37:30 +0100 From: Jan Kara To: Jeff Moyer Cc: Corrado Zoccolo , Jan Kara , jens.axboe@oracle.com, LKML , Chris Mason , Andrew Morton , Mike Galbraith Subject: Re: Performance regression in IO scheduler still there Message-ID: <20091110183730.GA27326@duck.suse.cz> References: <20091026172012.GC7233@duck.suse.cz> <4e5e476b0911051500j7587dd6dh975148475418efcf@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 910 Lines: 24 On Fri 06-11-09 09:14:53, Jeff Moyer wrote: > Corrado Zoccolo writes: > > > Hi Jeff, > > what hardware are you using for tests? > > I see aggregated random read bandwidth is larger than sequential read > > bandwidth, and write bandwidth greater than read. > > Is this a SAN with multiple independent spindles? > > Yeah, this is a single path to an HP EVA storage array. There are 24 or > so disks striped in the pool used to create the volume I am using. Jan, > could you repeat your tests with /sys/block/sdX/queue/iosched/low_latency > set to 0? I'll give it a spin tomorrow... Honza -- Jan Kara SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/