From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932342Ab2HVKyE (ORCPT ); Wed, 22 Aug 2012 06:54:04 -0400 Received: from cantor2.suse.de ([195.135.220.15]:48615 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756897Ab2HVKyB (ORCPT ); Wed, 22 Aug 2012 06:54:01 -0400 Date: Wed, 22 Aug 2012 11:48:06 +0100 From: Mel Gorman To: Jan Kara Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [MMTests] dbench4 async on ext3 Message-ID: <20120822104806.GD15058@suse.de> References: <20120620113252.GE4011@suse.de> <20120629111932.GA14154@suse.de> <20120723212146.GG9222@suse.de> <20120821220038.GA19171@quack.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20120821220038.GA19171@quack.suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 22, 2012 at 12:00:38AM +0200, Jan Kara wrote: > On Mon 23-07-12 22:21:46, Mel Gorman wrote: > > Configuration: global-dhp__io-dbench4-async-ext3 > > Result: http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-dbench4-async-ext3 > > Benchmarks: dbench4 > > > > Summary > > ======= > > > > In general there was a massive drop in throughput after 3.0. Very broadly > > speaking it looks like the Read operation got faster but at the cost of > > a big regression in the Flush operation. > > Mel, I had a look into this and it's actually very likely only a > configuration issue. In 3.1 ext3 started to default to enabled barriers > (barrier=1 in mount options) which is a safer but slower choice. When I set > barriers explicitely, I see no performance difference for dbench4 between > 3.0 and 3.1. > I've confirmed that disabling barriers fixed it, for one test machine and one test at least. I'll reschedule the tests to run with barriers disabled at some point in the future. Thanks for tracking it down, I was at least two weeks away before I got the chance to even look. -- Mel Gorman SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mel Gorman Subject: Re: [MMTests] dbench4 async on ext3 Date: Wed, 22 Aug 2012 11:48:06 +0100 Message-ID: <20120822104806.GD15058@suse.de> References: <20120620113252.GE4011@suse.de> <20120629111932.GA14154@suse.de> <20120723212146.GG9222@suse.de> <20120821220038.GA19171@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org To: Jan Kara Return-path: Content-Disposition: inline In-Reply-To: <20120821220038.GA19171@quack.suse.cz> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Aug 22, 2012 at 12:00:38AM +0200, Jan Kara wrote: > On Mon 23-07-12 22:21:46, Mel Gorman wrote: > > Configuration: global-dhp__io-dbench4-async-ext3 > > Result: http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-dbench4-async-ext3 > > Benchmarks: dbench4 > > > > Summary > > ======= > > > > In general there was a massive drop in throughput after 3.0. Very broadly > > speaking it looks like the Read operation got faster but at the cost of > > a big regression in the Flush operation. > > Mel, I had a look into this and it's actually very likely only a > configuration issue. In 3.1 ext3 started to default to enabled barriers > (barrier=1 in mount options) which is a safer but slower choice. When I set > barriers explicitely, I see no performance difference for dbench4 between > 3.0 and 3.1. > I've confirmed that disabling barriers fixed it, for one test machine and one test at least. I'll reschedule the tests to run with barriers disabled at some point in the future. Thanks for tracking it down, I was at least two weeks away before I got the chance to even look. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org