From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753873Ab0E1Se2 (ORCPT ); Fri, 28 May 2010 14:34:28 -0400 Received: from mvp.visionpro.com ([63.91.95.2]:2152 "EHLO mvpexchange120.machinevisionproducts.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751678Ab0E1Se1 convert rfc822-to-8bit (ORCPT ); Fri, 28 May 2010 14:34:27 -0400 User-Agent: Microsoft-Entourage/12.24.0.100205 Date: Fri, 28 May 2010 11:34:25 -0700 Subject: Slow Disk I/O From: "Brian D. McGrew" To: Message-ID: Thread-Topic: Slow Disk I/O Thread-Index: Acr+lGXMpv9Xq7EQPUO6EkQ0K1VVzQ== Mime-version: 1.0 Content-type: text/plain; charset="ISO-8859-1" Content-transfer-encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Good morning All! Iım running CentOS 5.4 x86_64 on a Dell T5500 with 3GB || 12GB or RAM. Iım running a 2.6.18-128.el5 kernel. There is a 500GB SATA drive connected to the onboard SATA controller. I can reproduce this problem with CentOS 5.4 i386 on the Dell T5500, T5400 and Optiplex 740ıs. So now, on to the problem... In our software, weıre reading in 5MP image files in the neighborhood of 500 to 1500 files at a time. Just a simple for() loop, open, read, close... Nothing fancy... When I have 3GB of RAM in the system, life is good.. Each read takes 8 to 10ms... This is a good thing! If I bump the memory up to 12GB, all of the reads are now taking 150 to 200ms. My default, va.swappines to set to 60... If I decrease this number, the problem gets much worse. If I up va.swappines to 100, the problem gets a little better, but not a whole lot. What should I be looking at??? -b