From: Ted Ts'o Subject: Re: ext4 performance regression 2.6.27-stable versus 2.6.32 and later Date: Thu, 29 Jul 2010 22:20:55 -0400 Message-ID: <20100730022055.GL4506@thunk.org> References: <4C508A54.7070002@uni-konstanz.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux , Ext4 Developers List , Karsten Schaefer To: Kay Diederichs Return-path: Received: from thunk.org ([69.25.196.29]:42379 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754953Ab0G3CU6 (ORCPT ); Thu, 29 Jul 2010 22:20:58 -0400 Content-Disposition: inline In-Reply-To: <4C508A54.7070002@uni-konstanz.de> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Jul 28, 2010 at 09:51:48PM +0200, Kay Diederichs wrote: > > When looking at the I/O statistics while the benchmark is running, we > see very choppy patterns for 2.6.32, but quite smooth stats for > 2.6.27-stable. Could you try to do two things for me? Using (preferably from a recent e2fsprogs, such as 1.41.11 or 12) run filefrag -v on the files created from your 2.6.27 run and your 2.6.32 run? Secondly can capture blktrace results from 2.6.27 and 2.6.32? That would be very helpful to understand what might be going on. Either would be helpful; both would be greatly appreciated. Thanks, - Ted