Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933424Ab0HEPyP (ORCPT ); Thu, 5 Aug 2010 11:54:15 -0400 Received: from isilmar-3.linta.de ([188.40.101.200]:47742 "EHLO linta.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756454Ab0HEPyN (ORCPT ); Thu, 5 Aug 2010 11:54:13 -0400 Date: Thu, 5 Aug 2010 17:53:57 +0200 From: Dominik Brodowski To: Chris Mason Cc: josef@redhat.com, Valdis.Kletnieks@vt.edu, Michael Monnerie , Christoph Hellwig , linux-raid@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com 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> Mail-Followup-To: Dominik Brodowski , Chris Mason , josef@redhat.com, Valdis.Kletnieks@vt.edu, Michael Monnerie , Christoph Hellwig , linux-raid@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com References: <20100805123649.GA18672@dhcp231-156.rdu.redhat.com> <20100805113240.GA29846@think> <20100805153519.GA7242@comet.dominikbrodowski.net> <20100805153943.GO29846@think> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100805153943.GO29846@think> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1617 Lines: 41 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 -- 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/