From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264652AbUFLGcD (ORCPT ); Sat, 12 Jun 2004 02:32:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264653AbUFLGcD (ORCPT ); Sat, 12 Jun 2004 02:32:03 -0400 Received: from smtp106.mail.sc5.yahoo.com ([66.163.169.226]:26216 "HELO smtp106.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S264652AbUFLGcA (ORCPT ); Sat, 12 Jun 2004 02:32:00 -0400 Message-ID: <40CAA358.9070603@yahoo.com.au> Date: Sat, 12 Jun 2004 16:31:52 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040401 Debian/1.6-4 X-Accept-Language: en MIME-Version: 1.0 To: Guy Van Sanden CC: linux-kernel@vger.kernel.org Subject: Re: PROBLEM: Heavy iowait on 2.6 kernels References: <1086942905.10540.69.camel@cronos.home.vsb> In-Reply-To: <1086942905.10540.69.camel@cronos.home.vsb> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Guy Van Sanden wrote: > I recently discovered why my new Gentoo server slows to a crawl on a > intermediate load on the 2.6 kernel series. The reason seems to be an > unusual amount of iowait. > I can reproduce this on two systems, one with a KT400 and and one with > Sis735 chipset. > > iostat -c 1 (or vmstat) while running something like bonnie produces > iowaits of 99%. > Any 2.6 kernel responds the same (regardless of the patchset), even > vanilla. (2.6.5-mm, 2.6.6-mm, 2.6.6-vanilla and 2.6.5-gentoo-r1). > Any 2.4-series kernel is fine. > Hi, can you try booting with elevator=deadline, please? Then include a vmstat 1 output for a 2.6 and a 2.4 kernel. I don't think 2.4 kernels will show iowait, so some real performance measurements would be helpful. Thanks