From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261568AbUEDXBi (ORCPT ); Tue, 4 May 2004 19:01:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261631AbUEDXBi (ORCPT ); Tue, 4 May 2004 19:01:38 -0400 Received: from [213.171.41.46] ([213.171.41.46]:7684 "EHLO kaamos.homelinux.net") by vger.kernel.org with ESMTP id S261568AbUEDXBf (ORCPT ); Tue, 4 May 2004 19:01:35 -0400 From: Alexey Kopytov Organization: MySQL AB To: Ram Pai Subject: Re: Random file I/O regressions in 2.6 Date: Wed, 5 May 2004 03:01:31 +0400 User-Agent: KMail/1.6.2 Cc: Andrew Morton , nickpiggin@yahoo.com.au, peter@mysql.com, linux-kernel@vger.kernel.org, axboe@suse.de References: <200405022357.59415.alexeyk@mysql.com> <1083683034.13688.7.camel@localhost.localdomain> <1083699554.13688.64.camel@localhost.localdomain> In-Reply-To: <1083699554.13688.64.camel@localhost.localdomain> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="koi8-r" Content-Transfer-Encoding: 7bit Message-Id: <200405050301.32355.alexeyk@mysql.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ram Pai wrote: >Without the patch: >------------------ >Time spent for test: 20.6661s > >no of times window reset because of hits: 0 >no of times window reset because of misses: 7 >no of times window was shrunk because of hits: 6716 >no of times the page request was non-contiguous: 5880 >no of times the page request was contiguous : 19639 > >With the patch: >-------------- >Time spent for test: 19.5370s > >no of times window got reset because of hits: 0 >no of times window got reset because of misses: 0 >no of times window was shrunk because of hits: 5844 >no of times the page request was non-contiguous: 5830 >no of times the page request was contiguous : 20232 > >Would be nice if Alexey tries the patch on his machine and sees any >major difference. Here's what I have (same hardware and test setups): Without the patch (but with Ram's patch applied): ------------------ Time spent for test: 125.4429s no of times window reset because of hits: 0 no of times window reset because of misses: 127 no of times window was shrunk because of hits: 1153 no of times the page request was non-contiguous: 3968 no of times the page request was contiguous : 10686 With the patch: --------------- Time spent for test: 86.5459s no of times window reset because of hits: 0 no of times window reset because of misses: 0 no of times window was shrunk because of hits: 1066 no of times the page request was non-contiguous: 5860 no of times the page request was contiguous : 18099 I wonder if there are some plans to further improve 2.6 behavior on this workload to match that of 2.4? Is the remaing regression a result of the different readahead handling, or it might be caused by IDE driver or I/O scheduler tuning? -- Alexey Kopytov, Software Developer MySQL AB, www.mysql.com Are you MySQL certified? www.mysql.com/certification