From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o75Frott093102 for ; Thu, 5 Aug 2010 10:53:51 -0500 Received: from linta.de (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 1B7DDC4FA52 for ; Thu, 5 Aug 2010 09:02:20 -0700 (PDT) Received: from linta.de (isilmar-3.linta.de [188.40.101.200]) by cuda.sgi.com with ESMTP id dLDlEfx33oYkC0Ie for ; Thu, 05 Aug 2010 09:02:20 -0700 (PDT) Date: Thu, 5 Aug 2010 17:53:57 +0200 From: Dominik Brodowski Subject: Re: direct-io regression [Was: How to track down abysmal performance ata - raid1 - crypto - vg/lv - xfs] Message-ID: <20100805155357.GA8245@comet.dominikbrodowski.net> References: <20100805123649.GA18672@dhcp231-156.rdu.redhat.com> <20100805113240.GA29846@think> <20100805153519.GA7242@comet.dominikbrodowski.net> <20100805153943.GO29846@think> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20100805153943.GO29846@think> 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: Chris Mason Cc: Michael Monnerie , linux-raid@vger.kernel.org, Valdis.Kletnieks@vt.edu, linux-kernel@vger.kernel.org, xfs@oss.sgi.com, Christoph Hellwig , dm-devel@redhat.com, josef@redhat.com On Thu, Aug 05, 2010 at 11:39:43AM -0400, Chris Mason wrote: > On Thu, Aug 05, 2010 at 05:35:19PM +0200, Dominik Brodowski wrote: > > On Thu, Aug 05, 2010 at 07:32:40AM -0400, Chris Mason wrote: > > > But, I'm surprised your drive is doing 8K dio reads at 16MB/s, that > > > seems a little high. > > > > Well, that's what it does: > > > > # $ dd if=/dev/mapper/vg0-home_crypt of=/dev/zero iflag=direct bs=8k count=131072 seek=131072 > > # 131072+0 records in > > # 131072+0 records out > > # 1073741824 bytes (1.1 GB) copied, 62.0177 s, 17.3 MB/s > > Can I ask you to do the test directly to the real honest to goodness > drive? If it were an SSD I'd be less surprised, but then the extra > submits shouldn't hurt the ssd that much either. >>From lower the chain up to the device: # LANG=EN dd if=/dev/mapper/vg0-root_crypt of=/dev/zero bs=8k count=131072 seek=393300 iflag=direct 131072+0 records in 131072+0 records out 1073741824 bytes (1.1 GB) copied, 63.1217 s, 17.0 MB/s # LANG=EN dd if=/dev/mapper/vg0-root of=/dev/zero bs=8k count=131072 seek=393300 iflag=direct 131072+0 records in 131072+0 records out 1073741824 bytes (1.1 GB) copied, 43.2335 s, 24.8 MB/s # LANG=EN dd if=/dev/sda5 of=/dev/zero bs=8k count=131072 seek=393300 iflag=direct 131072+0 records in 131072+0 records out 1073741824 bytes (1.1 GB) copied, 42.0868 s, 25.5 MB/s Best, Dominik _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs