From: Christian Kujau Subject: Re: [Jfs-discussion] benchmark results Date: Sat, 26 Dec 2009 11:06:38 -0800 Message-ID: <4B365EBE.5050804@nerdbynature.de> References: <19251.26403.762180.228181@tree.ty.sabi.co.uk> <20091224212756.GM21594@thunk.org> <20091225161453.GD32757@thunk.org> <20091225162238.GB19303@bitmover.com> <4B36333B.3030600@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Larry McVoy , tytso@mit.edu, jfs-discussion@lists.sourceforge.net, linux-nilfs@vger.kernel.org, xfs@oss.sgi.com, reiserfs-devel@vger.kernel.org, Peter Grandi , ext-users , linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org To: jim owens Return-path: Received: from moutng.kundenserver.de ([212.227.17.10]:60180 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752576AbZLZTHV (ORCPT ); Sat, 26 Dec 2009 14:07:21 -0500 In-Reply-To: <4B36333B.3030600@hp.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 26.12.09 08:00, jim owens wrote: >> I was using "sync" to make sure that the data "should" be on the disks > > Good, but not good enough for many tests... info sync [...] > On Linux, sync is only guaranteed to schedule the dirty blocks for > writing; it can actually take a short time before all the blocks are > finally written. Noted, many times already. That's why I wrote "should be" - but in this special scenario (filesystem speed tests) I don't care for file integrity: if I pull the plug after "sync" and some data didn't make it to the disks, I'll only look if the testscript got all the timestamps and move on to the next test. I'm not testing for "filesystem integrity after someone pulls the plug" here. And remember, I'm doing "sync" for all the filesystems tested, so the comparison still stands. Christian.