From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262623AbULPGpr (ORCPT ); Thu, 16 Dec 2004 01:45:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262624AbULPGpq (ORCPT ); Thu, 16 Dec 2004 01:45:46 -0500 Received: from web53305.mail.yahoo.com ([206.190.39.234]:21637 "HELO web53305.mail.yahoo.com") by vger.kernel.org with SMTP id S262623AbULPGpi (ORCPT ); Thu, 16 Dec 2004 01:45:38 -0500 Comment: DomainKeys? See http://antispam.yahoo.com/domainkeys DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; b=cONyJpuQR5iOowKp33LaqPoZhyvZlLE5KKOra4+38Qh6/+MN82oPAnE21zDoMGsdzkQwEsnh3MkMlfzXbJIRdWbwRpxujLJwZGxSN0Wji/imTrlqLDEYTCKgXT48cXvrLW3GTMSVB7FGGxpXstWbPXgVPIveqwQtUu6Nyg1bPVY= ; Message-ID: <20041216064538.93385.qmail@web53305.mail.yahoo.com> Date: Wed, 15 Dec 2004 22:45:38 -0800 (PST) From: firnnauriel Subject: bcopy's performance on 2.4.20 (Redhat) and 2.40.20-8um (UML) To: linux-kernel@vger.kernel.org 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 Greetings to all! I would like to ask for your advice regarding this question: "In general, is the memcpy"s performance on UML (User Mode Linux) environment better than the host OS? If that is the case, can you give the reason behind it (ex. UML"s architecture)?" Here"s the evironment: HOST OS: Redhat 9 (kernel 2.4.20-8) Brand/Model: Dell PowerEdge 2600 CPU: Intel Xeon 2.4 GHz Memory: 2 GB Disk Space: 73 GB UML Kernel version : 2.40.20-lsm1-8um Allocated Mem : 256MB I used lmbench-2.0.4 for the bandwith and latency testing. here"s the result: host memcpy : 597.1 MB/s (higher is better) page fault : 2.00000 (smaller is better) uml memcpy : 668.4 page fault : 48.0 The result in page fault might be because of low memory allocated in UML. But the question is, why is the memcpy on UML (668.4 MB/s) performs faster that the host OS? I already asked the developer of lmbench, and he adviced me to ask this question to the linux kernel mailing list. I would really appreciate any inputs and advice. Thank you! __________________________________ Do you Yahoo!? Jazz up your holiday email with celebrity designs. Learn more. http://celebrity.mail.yahoo.com