From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262710AbTGFRGc (ORCPT ); Sun, 6 Jul 2003 13:06:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266706AbTGFRG0 (ORCPT ); Sun, 6 Jul 2003 13:06:26 -0400 Received: from unthought.net ([212.97.129.24]:23215 "EHLO unthought.net") by vger.kernel.org with ESMTP id S262710AbTGFRGY (ORCPT ); Sun, 6 Jul 2003 13:06:24 -0400 Date: Sun, 6 Jul 2003 19:20:56 +0200 From: Jakob Oestergaard To: Mark Hahn Cc: Charles-Edouard Ruault , Francois Romieu , linux-kernel@vger.kernel.org Subject: Re: kernel 2.4.21 , large disk write => system crawls Message-ID: <20030706172056.GB9705@unthought.net> Mail-Followup-To: Jakob Oestergaard , Mark Hahn , Charles-Edouard Ruault , Francois Romieu , linux-kernel@vger.kernel.org References: <3F04AE6A.8000504@ruault.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 03, 2003 at 06:56:24PM -0400, Mark Hahn wrote: > > >>when i do a large disk write operation ( copy a big file for example ), > > >>the whole system becomes very busy ( system goes into 99% cpu > > it's not write-specific. you can see below that you're somehow > managing to trigger roughly two interrupts per *either* bi or bo. > for a normal IDE setup, you should see one interrupt per 16-64K > under average use. it's almost like your sys somehow thinks > that it can only transfer 1 sector per interrupt! The system is 90% in kernel when writing. That's bad (unless you're maxing out your PCI busses or main memory bandwidth of course ;) The IDE disks are most likely not running DMA. > > > everytime i experience a slowdown, there's a 'big' number in the io (bo) > > column. > > no, it's basically in=2*(bi+bo), as if your system somehow believes > it can only do a single sector per interrupt (PIO and -m1 perhaps?) > it should be more like 32K per interrupt. Try: hdparm -d1 /dev/hda -- ................................................................ : jakob@unthought.net : And I see the elder races, : :.........................: putrid forms of man : : Jakob Østergaard : See him rise and claim the earth, : : OZ9ABN : his downfall is at hand. : :.........................:............{Konkhra}...............: