From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754056AbYIXSRS (ORCPT ); Wed, 24 Sep 2008 14:17:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751909AbYIXSRE (ORCPT ); Wed, 24 Sep 2008 14:17:04 -0400 Received: from terminus.zytor.com ([198.137.202.10]:46113 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751517AbYIXSRD (ORCPT ); Wed, 24 Sep 2008 14:17:03 -0400 Message-ID: <48DA8402.1090701@zytor.com> Date: Wed, 24 Sep 2008 11:16:34 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: cristi.magherusan@net.utcluj.ro CC: Yan Li , linux-kernel@vger.kernel.org, Ingo Molnar , joerg.roedel@amd.com, rjmaomao@gmail.com, Yinghai Lu , Thomas Gleixner , nancydreaming@gmail.com Subject: Re: [PATCH 1/2] VMware guest detection for x86 and x86-64 References: <48D12490.5010003@zytor.com> <48da36b9.160d6e0a.22a5.ffffec9d@mx.google.com> <1222265424.5708.5.camel@localhost> <20080924142322.GA21049@yantp.cn.ibm.com> <1222279994.27604.2.camel@localhost> In-Reply-To: <1222279994.27604.2.camel@localhost> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Cristi Magherusan wrote: > On Wed, 2008-09-24 at 22:23 +0800, Yan Li wrote: >> On Wed, Sep 24, 2008 at 05:10:24PM +0300, Cristi Magherusan wrote: >>> On Wed, 2008-09-24 at 20:22 +0800, Yan Li wrote: >>>> Detects whether we are running as a VMware guest or not. Detection is >>>> based upon DMI vendor string. >>>> >>>> It provides a function: >>>> int is_vmware_guest(void) >>>> that can be used easily to detect if we are running as a VMware guest >>>> or not. >>> We can also use this feature to force the HZ value to 100 or 250 at most >>> when running in a virtual environment, since VirtualBox had some issues >>> with this by taking a lot of CPU time when the HZ was set to 1000. >> That's good. But this function is used for detecting VMware guest >> only. Do you think VMware also suffers from this problem? >> > I don't know for sure about VMware, but someone who has it installed can > try it. I had this issue with a CentOS 5-server virtual machine > downloaded from http://www.thoughtpolice.co.uk/vmware/ > > The fix consisted in using a kernel compiled with the HZ value set to > 100 instead of the default which was 1000. > HZ is a compile-time constant, though. Changing that would require adding a bunch of general divides, at the very least. -hpa