From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265985AbUEUVNk (ORCPT ); Fri, 21 May 2004 17:13:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266025AbUEUVNk (ORCPT ); Fri, 21 May 2004 17:13:40 -0400 Received: from [213.171.41.46] ([213.171.41.46]:6916 "EHLO kaamos.homelinux.net") by vger.kernel.org with ESMTP id S265985AbUEUVNg (ORCPT ); Fri, 21 May 2004 17:13:36 -0400 From: Alexey Kopytov Organization: MySQL AB To: Andrew Morton Subject: Re: Random file I/O regressions in 2.6 [patch+results] Date: Sat, 22 May 2004 01:13:30 +0400 User-Agent: KMail/1.6.2 Cc: linuxram@us.ibm.com, nickpiggin@yahoo.com.au, peter@mysql.com, linux-kernel@vger.kernel.org, axboe@suse.de References: <200405022357.59415.alexeyk@mysql.com> <200405200506.03006.alexeyk@mysql.com> <20040520145902.27647dee.akpm@osdl.org> In-Reply-To: <20040520145902.27647dee.akpm@osdl.org> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200405220113.31136.alexeyk@mysql.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Friday 21 May 2004 01:59, Andrew Morton wrote: >The patches in Linus's tree improve sysbench significantly here. It's a >256MB 2-way with IDE disks, writeback caching enabled: > >sysbench --num-threads=16 --test=fileio --file-total-size=2G > --file-test-mode=rndrw run > >2.4.27-pre2, ext2: > > Time spent for test: 61.0240s > 0.06s user 6.03s system 4% cpu 2:05.95 total > Time spent for test: 60.8456s > 0.11s user 5.49s system 4% cpu 2:04.94 total > >2.6.6-bk, AS, ext2: > > Time spent for test: 62.5316s > 0.05s user 5.27s system 4% cpu 2:01.28 total > Time spent for test: 62.7401s > 0.04s user 5.17s system 4% cpu 2:00.50 total I ran the tests with a configuration as close to yours as possible. Here are the results for mem=256M, 2G total file size (ext3): 2.4.25: Time spent for test: 79.4146s 0.20user 16.08system 3:20.29elapsed 8%CPU Time spent for test: 78.9797s 0.11user 15.84system 3:19.76elapsed 7%CPU 2.6.6-bk, AS: Time spent for test: 81.2208s 0.13user 17.97system 3:13.30elapsed 9%CPU Time spent for test: 82.5538s 0.14user 18.00system 3:14.88elapsed 9%CPU This correlates very well your results. But when I returned back to my original configuration (mem=640M, 3G total file size), I got the following: 2.4.25: Time spent for test: 77.5377s 2.6.6-bk, AS: Time spent for test: 83.1929s It seems like the smaller file size just hides the regression, but I have to run some more tests to ensure this. >I don't know why you're still seeing significant discrepancies. > >What sort of disk+controller system are you using? If scsi, what is the >tag queue depth set to? Is writeback caching enabled on the disk? It's IDE disk without TCQ support with writeback caching enabled. -- Alexey Kopytov, Software Developer MySQL AB, www.mysql.com Are you MySQL certified? www.mysql.com/certification