From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262554AbTIUUKa (ORCPT ); Sun, 21 Sep 2003 16:10:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262555AbTIUUKa (ORCPT ); Sun, 21 Sep 2003 16:10:30 -0400 Received: from sccrmhc11.comcast.net ([204.127.202.55]:26869 "EHLO sccrmhc11.comcast.net") by vger.kernel.org with ESMTP id S262554AbTIUUK3 (ORCPT ); Sun, 21 Sep 2003 16:10:29 -0400 Date: Sun, 21 Sep 2003 16:10:09 -0400 (EDT) From: Matt Hahnfeld X-X-Sender: hahnfld@sotec To: linux-kernel@vger.kernel.org Subject: SLOW machine when HIGHMEM enabled (1gb memory, kernel 2.4.22) Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I have an ASUS P4P800-VM motherboard with 2 sticks of 512mb PC3200 and a single 2.4 ghz P4 processor. The kernel is vanilla 2.4.22 configured for SMP (hyperthreading). When I use a kernel with high memory support off, I get good performance (despite not being able to use some of my memory). When I enable CONFIG_HIGHMEM4G the remaining memory is detected, but the machine takes a big performance hit and starts running very slow -- ie. kernel compilation looks like it would take 5 days instead of 5 minutes. /proc/meminfo doesn't look particularly strange and no strange log messages show up -- everything just runs slow... CONFIG_HIGHMEM64G produces the same results... Any suggestions?