From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261877AbVFMRBb (ORCPT ); Mon, 13 Jun 2005 13:01:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261880AbVFMRBa (ORCPT ); Mon, 13 Jun 2005 13:01:30 -0400 Received: from mailhub3.nextra.sk ([195.168.1.146]:55556 "EHLO mailhub3.nextra.sk") by vger.kernel.org with ESMTP id S261877AbVFMRB2 (ORCPT ); Mon, 13 Jun 2005 13:01:28 -0400 Message-ID: <42ADBBE0.1030901@rainbow-software.org> Date: Mon, 13 Jun 2005 19:01:20 +0200 From: Ondrej Zary User-Agent: Mozilla Thunderbird 1.0.2 (X11/20050317) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Alan Cox CC: Nick Piggin , Grant Coady , Linux Kernel Mailing List Subject: Re: Odd IDE performance drop 2.4 vs 2.6? References: <42AD6362.1000109@rainbow-software.org> <1118669975.13260.23.camel@localhost.localdomain> <42AD92F2.7080108@yahoo.com.au> <1118675343.13773.1.camel@localhost.localdomain> In-Reply-To: <1118675343.13773.1.camel@localhost.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Alan Cox wrote: > On Llu, 2005-06-13 at 15:06, Nick Piggin wrote: > >>>Make sure you have pre-empt disabled and the antcipatory I/O scheduler >>>disabled. >>> >> >>I don't think that those could explain it. > > > Try it and see. The anticipatory I/O scheduler does horrible things to > my IDE streaming performance numbers and to swap performance. It tries > to merge I/O by delaying it which is deeply ungood when it comes to IDE > streaming even if its good for general I/O. Changing the scheduler did not help (the results are about the same with any of the 4 schedulers). Read ahead is already set to 256 (increasing to 1024 did not help either). Kernel compilation takes too much time here so I didn't test with preempt disabled. The drive is WD300BB (7200RPM) in UDMA2 mode. root@pentium:~# cat /sys/block/hda/queue/scheduler noop anticipatory [deadline] cfq root@pentium:~# hdparm -tT /dev/hda /dev/hda: Timing cached reads: 176 MB in 2.00 seconds = 88.00 MB/sec Timing buffered disk reads: 34 MB in 3.02 seconds = 11.26 MB/sec root@pentium:~# hdparm /dev/hda /dev/hda: multcount = 16 (on) IO_support = 1 (32-bit) unmaskirq = 1 (on) using_dma = 1 (on) keepsettings = 1 (on) readonly = 0 (off) readahead = 256 (on) geometry = 58168/16/63, sectors = 58633344, start = 0 -- Ondrej Zary