From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o7DEDMk5064540 for ; Fri, 13 Aug 2010 09:13:23 -0500 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id D05A94B476F for ; Fri, 13 Aug 2010 07:13:47 -0700 (PDT) Received: from mail.internode.on.net (bld-mail18.adl2.internode.on.net [150.101.137.103]) by cuda.sgi.com with ESMTP id rldXR4hfpoYT0V2k for ; Fri, 13 Aug 2010 07:13:47 -0700 (PDT) Date: Sat, 14 Aug 2010 00:13:44 +1000 From: Dave Chinner Subject: Re: observed significant performance improvement using "delaylog" in Message-ID: <20100813141344.GE10429@dastard> References: <201008121346.30760.eye.of.the.8eholder@gmail.com> <4C6516CA.2010602@hardwarefreak.com> <201008131235.45050@zmi.at> <20100813122907.GA14650@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20100813122907.GA14650@infradead.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Christoph Hellwig Cc: Michael Monnerie , Stan Hoeppner , xfs@oss.sgi.com On Fri, Aug 13, 2010 at 08:29:07AM -0400, Christoph Hellwig wrote: > On Fri, Aug 13, 2010 at 12:35:44PM +0200, Michael Monnerie wrote: > > On Freitag, 13. August 2010 Stan Hoeppner wrote: > > > Some benchmark results maybe worth a look: > > > http://btrfs.boxacle.net/repository/raid/2.6.35-rc5/2.6.35-rc5/ > > > > Thanks - it would have been great to see xfs with delaylog in that > > comparison, but the graphs are very very nice. > > > > XFS seems performing better the more threads there are, just in "large > > file random reads" it's the slowest - why this? > > Any idea who is doing these runs? IIRC the tests are run by someone from IBM, but I cannot remember who it is. > Once we figure out what that large > file random reads loads is I'm sure we could fix it soon. >>From http://btrfs.boxacle.net/: Random Reads (raid, single-disk) Start with 1024 files. 100 MB files on the raid system. 35 MB files on the single-disk system. Each thread reads a fixed amount of data from a random location in one file using 4 kB reads. 5 MB reads on the raid system. 1 MB reads on the single-disk system. So it's not a small random read workload (100GB data set), so the files on XFS are probably more spread out over multiple AGs and hence further apart than other filesystems. Hence a greater average seek distance, hence it slower throughput.... > And asking > him/her to add -o delaylog would also be good. Yes, that would be an interesting comparison... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs