From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 19 Aug 2001 15:50:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 19 Aug 2001 15:50:19 -0400 Received: from [24.93.35.62] ([24.93.35.62]:24841 "EHLO ns1.austin.rr.com") by vger.kernel.org with ESMTP id ; Sun, 19 Aug 2001 15:50:12 -0400 From: "Marvin Justice" To: "'Matthias Schniedermeyer'" , "'Alan Cox'" Cc: Subject: RE: Strange Slowdown Date: Sun, 19 Aug 2001 14:53:46 -0500 Message-ID: <000001c128e8$a8f31070$36481c18@ujx7u> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook CWS, Build 9.0.2416 (9.0.2910.0) In-Reply-To: <20010818182300.A15860@citd.de> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > > After i switched "High Memory-Support" to "OFF"(4GB > Before) the speed went > > > to normal, but now less than half RAM is used. > > > Any suggestions? > > > > This sounds like the top of memory is running uncached due > to wrong mtrr > > settings from the BIOS. Can you post your /proc/mtrr > > Because of other reasons i'm back to 2.2.19 > > /proc/mtrr from 2.2.19 show this > -- /proc/mtrr -- > reg00: base=0x00000000 ( 0MB), size=1024MB: write-back, count=1 > reg01: base=0x40000000 (1024MB), size= 512MB: write-back, count=1 > reg02: base=0x60000000 (1536MB), size= 256MB: write-back, count=1 > reg03: base=0x70000000 (1792MB), size= 128MB: write-back, count=1 > reg04: base=0x78000000 (1920MB), size= 64MB: write-back, count=1 > reg05: base=0x7c000000 (1984MB), size= 32MB: write-back, count=1 > -- end -- > (32MB "missing". Seems like Linux uses these "missing" MBs.) > > For the 2.4.X-Kernel i had switched off the MTRR-Kernel-Option! > > Maybe i should try it another time with MTRR-Support switched on. > Or i should use "mem=2016M". > I had a similar problem which could be solved by either passing the "mem=" option at boot time as you suggest(in which case you permanently lose the upper 32MB) or by using the /proc/mtrr interface ( as described in Documentation/mtrr.txt) to assign the "missing" region. For your system you might try something like: echo "base=0x7e000000 size=0x2000000 type=write-back" >| /proc/mtrr Marvin Justice