From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261729AbULGBkV (ORCPT ); Mon, 6 Dec 2004 20:40:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261730AbULGBkV (ORCPT ); Mon, 6 Dec 2004 20:40:21 -0500 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:57288 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S261729AbULGBkM (ORCPT ); Mon, 6 Dec 2004 20:40:12 -0500 Date: Mon, 6 Dec 2004 17:43:31 -0200 From: Marcelo Tosatti To: Alain Tesio Cc: linux-kernel@vger.kernel.org Subject: Re: HIGHMEM=4G slows down ps2pdf with 2.4.28 Message-ID: <20041206194331.GC2282@dmt.cyclades> References: <20041201232522.6e39c954@alain> <20041202190815.GA2843@dmt.cyclades> <20041203215819.15bab008@alain> <20041206184118.GA2282@dmt.cyclades> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041206184118.GA2282@dmt.cyclades> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 06, 2004 at 04:41:18PM -0200, Marcelo Tosatti wrote: > On Fri, Dec 03, 2004 at 09:58:19PM +0100, Alain Tesio wrote: > > On Thu, 2 Dec 2004 17:08:15 -0200 > > Marcelo Tosatti wrote: > > > > > On Wed, Dec 01, 2004 at 11:25:22PM +0100, Alain Tesio wrote: > > > > Hi, > > > > > > > > With a 2.4.28 kernel, 1.5 Go RAM and nothing exotic, everything works fine > > > > with CONFIG_HIGHMEM4G and CONFIG_HIGHMEM=y except that > > > > ps2pdf is about 30 times slower > > > > > How does /proc/mtrr look like? > > > > > > Maybe some of your memory is configured as uncacheable. > > > > reg00: base=0x00000000 ( 0MB), size=1024MB: write-back, count=1 > > reg01: base=0x40000000 (1024MB), size= 256MB: write-back, count=1 > > reg02: base=0x50000000 (1280MB), size= 128MB: write-back, count=1 > > reg03: base=0x58000000 (1408MB), size= 64MB: write-back, count=1 > > reg04: base=0x5c000000 (1472MB), size= 32MB: write-back, count=1 > > reg05: base=0x5e000000 (1504MB), size= 16MB: write-back, count=1 > > > > I don't think that the hosting company played with the bios settings, > > and I don't do anything special with memory. > > Alain, > > All memory is correctly configured in MTRR it seems (all of it is write-back cacheable). > > Do you have CONFIG_HIGHIO=y ? That might help a lot. The kernel has to use > bounce buffers for IO otherwise. However you report 30x slower without HIGHMEM - thats a bit too much for the added overhead of bounce buffers. Anyway, try CONFIG_HIGHIO=y if you dont have it configured this way.