Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932231Ab0HDKZa (ORCPT ); Wed, 4 Aug 2010 06:25:30 -0400 Received: from isilmar-3.linta.de ([188.40.101.200]:38451 "EHLO linta.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756253Ab0HDKZ3 (ORCPT ); Wed, 4 Aug 2010 06:25:29 -0400 Date: Wed, 4 Aug 2010 12:25:26 +0200 From: Dominik Brodowski To: Michael Monnerie , Christoph Hellwig Cc: linux-raid@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com Subject: Re: How to track down abysmal performance ata - raid1 - crypto - vg/lv - xfs Message-ID: <20100804102526.GB13766@isilmar-3.linta.de> Mail-Followup-To: Dominik Brodowski , Michael Monnerie , Christoph Hellwig , linux-raid@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com References: <20100804073546.GA7494@comet.dominikbrodowski.net> <20100804085039.GA11671@infradead.org> <20100804091317.GA27779@isilmar-3.linta.de> <20100804092122.GA2998@infradead.org> <20100804073546.GA7494@comet.dominikbrodowski.net> <201008041116.09822@zmi.at> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100804092122.GA2998@infradead.org> <201008041116.09822@zmi.at> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2382 Lines: 58 Hey, many thanks for your feedback. It seems the crypto step is the culprit: Reading 1.1 GB with dd, iflag=direct, bs=8k: /dev/sd* 35.3 MB/s ( 90 %) /dev/md* 39.1 MB/s (100 %) /dev/mapper/md*_crypt 3.9 MB/s ( 10 %) /dev/mapper/vg1-* 3.9 MB/s ( 10 %) The "good" news: it also happens on my notebook, even though it has a different setup (no raid, disk -> lv/vg -> crypt). On my notebook, I'm more than happy to test out different kernel versions, patches etc. /dev/sd* 17.7 MB/s (100 %) /dev/mapper/vg1-* 16.2 MB/s ( 92 %) /dev/mapper/*_crypt 3.1 MB/s ( 18 %) On a different system, a friend of mine reported (with 2.6.33): /dev/sd* 51.9 MB/s (100 %) dm-crypt 32.9 MB/s ( 64 %) This shows that the speed drop when using dmcrypt is not always a factor of 5 to 10... Btw, it occurs both with aes-lrw-benbi and aes-cbc-essiv:sha256 , and (on my notebook) the CPU is mostly idling or waiting. Best, Dominik PS: Bonnie output: Writing intelligently...done Rewriting...done Reading intelligently...done start 'em...done...done...done... Create files in sequential order...done. Stat files in sequential order...done. Delete files in sequential order...done. Create files in random order...done. Stat files in random order...done. Delete files in random order...done. Version 1.03d ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP ABCABCABCABCABC 16G 60186 4 24796 4 53386 5 281.1 1 ------Sequential Create------ --------Random Create-------- -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 3176 16 +++++ +++ 4641 28 5501 20 +++++ +++ 2286 9 ABCABCABCABCABCABC,16G,,,60186,4,24796,4,,,53386,5,281.1,1,16,3176,16,+++++,+++,4641,28,5501,20,+++++,+++,2286,9 -- 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/