From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754114Ab0CWUBY (ORCPT ); Tue, 23 Mar 2010 16:01:24 -0400 Received: from 2605ds1-ynoe.0.fullrate.dk ([90.184.12.24]:41563 "EHLO shrek.krogh.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753894Ab0CWUBX (ORCPT ); Tue, 23 Mar 2010 16:01:23 -0400 X-Greylist: delayed 568 seconds by postgrey-1.27 at vger.kernel.org; Tue, 23 Mar 2010 16:01:22 EDT Message-ID: <4BA91BD2.2010700@krogh.cc> Date: Tue, 23 Mar 2010 20:51:46 +0100 From: Jesper Krogh User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Ben Gamari , linux-kernel Subject: Re: Poor interactive performance with I/O loads with fsync()ing References: <4b9fa440.12135e0a.7fc8.ffffe745@mx.google.com> In-Reply-To: <4b9fa440.12135e0a.7fc8.ffffe745@mx.google.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ben Gamari wrote: > Hey all, > > Recently I started using the Xapian-based notmuch mail client for everyday > use. One of the things I was quite surprised by after the switch was the > incredible hit in interactive performance that is observed during database > updates. Things are particularly bad during runs of 'notmuch new,' which scans > the file system looking for new messages and adds them to the database. > Specifically, the worst of the performance hit appears to occur when the > database is being updated. I would suggest that you include a 2.6.31 kernel in your testing. I have seen something that seems like "huge" stalls in 2.6.32 but I havent been able to "dig into it" to find more. In 2.6.32 I have seen IO-wait numbers around 80% on a 16 core machine with 128GB of memory and load-numbers over 120 under workloads that didn't make 2.6.31 sweat at all. Filesystems are a mixture of ext3 and ext4 (so it could be the barriers)? -- Jesper