From: Theodore Tso Subject: Re: Performance of ext4 Date: Thu, 19 Jun 2008 11:56:45 -0400 Message-ID: <20080619155645.GA8582@mit.edu> References: <18513.345.553912.449710@frecb006361.adech.frec.bull.fr> <20080612131928.GB18229@mit.edu> <20080612180605.GD22481@skywalker> <20080616175408.GF3279@atrey.karlin.mff.cuni.cz> <20080616181353.GA20686@skywalker> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Aneesh Kumar K.V" , Jan Kara , Solofo.Ramangalahy@bull.net, Nick Dokos , linux-ext4@vger.kernel.org, linux-kernel To: Holger Kiehl Return-path: Received: from www.church-of-our-saviour.org ([69.25.196.31]:45778 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751185AbYFSP6D (ORCPT ); Thu, 19 Jun 2008 11:58:03 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Jun 17, 2008 at 11:42:36AM +0000, Holger Kiehl wrote: > Note how the size of file results.24033.helena.dwd.de changes from > 9230 before the test to 8208 bytes after the test. Also note the > date both have the same timestamp "2008-06-17 04:35". I have made a > copy of results.24033.helena.dwd.de before the test and compared it > with that after the test. The file is just truncated by 1022 bytes > and there is no garbage. So the corruption is always a truncation, correct? Did you notice the problem with ext4 w/o the patch queue? I have a suspicion that the problem may have been introduced by the delayed allocation code, but I don't have hard evidence. When you rerun your benchmark (which seems to be the closest thing we have to a reproduction case), it would be interesting to know if the problem goes away with -o nodelalloc (again, it would localize where we need to look). Thanks, regards, - Ted