From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gilles PIETRI Subject: Clock issue in Windows XP guests Date: Thu, 04 Mar 2010 10:43:50 +0100 Message-ID: <4B8F80D6.1030703@gilouweb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from dingo.eclaireurs.org ([91.121.140.153]:37077 "EHLO dingo.eclaireurs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755509Ab0CDJoP (ORCPT ); Thu, 4 Mar 2010 04:44:15 -0500 Received: from localhost (localhost.localdomain [127.0.0.1]) by dingo.eclaireurs.org (Postfix) with ESMTP id 989D13DE84 for ; Thu, 4 Mar 2010 10:44:11 +0100 (CET) Received: from dingo.eclaireurs.org ([127.0.0.1]) by localhost (dingo.eclaireurs.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id lb1pAfMZ3oiJ for ; Thu, 4 Mar 2010 10:44:11 +0100 (CET) Received: from [192.168.51.29] (xbn44-1-82-67-143-163.fbx.proxad.net [82.67.143.163]) by dingo.eclaireurs.org (Postfix) with ESMTPSA id 1174C3DE83 for ; Thu, 4 Mar 2010 10:44:11 +0100 (CET) Sender: kvm-owner@vger.kernel.org List-ID: Hi, I have a host running a 2.6.32.7 kernel, and I'm using qemu-kvm 0.12.2. I have multiple guests, and one of them is running Windows XP. If I stare at the clock, I see that every now & then (~5s), it slows down a bit, and then try to cope with it. If I run some NTP synchronization software like ntpd, the offset is as high as 1s lost every 10s or so, which makes it impossible to use anything time based on the guest (audio stuff, mainly). I tried messing (as said on IRC) with the -rtc parameters, but to no avail. I tried the driftfix=slew option found in the --help output, but it says that driftfix is not a valid setting for rtc.. And anyway, I have no idea what this does (I'll be reading about it probably...) I've seen something remotely connected to this on the proxmox forum, but it was not that helpful (and proxmox runs qemu 0.11.x as it seems): http://forum.proxmox.com/threads/2050-Slow-clock-time-drift-in-windows-guests?p=17962 I remember using the -rtc-td-hack (and in fact, just read again about it here: http://forum.proxmox.com/threads/2381-Recommended-clock-source-for-KVM-guests), but it's not there anymore in 0.12.x, and I have no idea what it used to do (going on for some reading as well, when I have some time ;)) Oh, and the guests running linux are working just fine, and have no clock issue. Has anyone encountered such a problem? Regards, Gilou