From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261170AbULWHIH (ORCPT ); Thu, 23 Dec 2004 02:08:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261172AbULWHIG (ORCPT ); Thu, 23 Dec 2004 02:08:06 -0500 Received: from holomorphy.com ([207.189.100.168]:2485 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S261170AbULWHIF (ORCPT ); Thu, 23 Dec 2004 02:08:05 -0500 Date: Wed, 22 Dec 2004 23:07:57 -0800 From: William Lee Irwin III To: Paramveer Singh Cc: linux-kernel@vger.kernel.org Subject: Re: 2.4.21 opteron 32 Gig RAM has 10k block writes/sec on running posgresql 7.4.6 disk i/o intensive app Message-ID: <20041223070757.GZ771@holomorphy.com> References: <11f564b9041222225638905557@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <11f564b9041222225638905557@mail.gmail.com> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 23, 2004 at 12:26:48PM +0530, Paramveer Singh wrote: > we are using a RedHat AS3 U3 box (2.4.21-4.ELsmp) to run a very > intensive database app which does a _huge_ number of inserts durnig > the data generation phase. However, we are noticing a unexpected > performance drops with user cpu utilization numbers falling to near 0. > most of the cpu is used up in iowait. > CPU states: cpu user nice system irq softirq iowait idle > total 2.0% 0.0% 7.6% 0.0% 0.0% 362.4% 27.2% > /proc/slabinfo showed huge numbers in buffer_head. The line was: > buffer_head 4908452 4962249 200 260854 261171 1 : 16000 4000 Please try to reproduce on a more recent RHEL3, e.g. RHEL3-U4 released today. -- wli