From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: kvm-77 Excessive Disk Access causes real time clock hang! Date: Fri, 24 Apr 2009 20:30:27 -0300 Message-ID: <20090424233027.GD15714@amt.cnet> References: <49F1DAF5.2060805@rdsoftware.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, Gleb Natapov To: Erik Rull Return-path: Received: from mx2.redhat.com ([66.187.237.31]:41141 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753503AbZDXXbv (ORCPT ); Fri, 24 Apr 2009 19:31:51 -0400 Content-Disposition: inline In-Reply-To: <49F1DAF5.2060805@rdsoftware.de> Sender: kvm-owner@vger.kernel.org List-ID: Erik, On Fri, Apr 24, 2009 at 05:29:57PM +0200, Erik Rull wrote: > Hi all, > > I'm running kvm-77 and windows xp as guest. When I start the > defragmentation of the virtualized drive within the windows guest (well > this is not a fine way, but it should work :-)), the real time clock > starts hanging - I recognized that because some underlying hardware with > own timers began to run out of synchronization. I did some research, took > a stopwatch and measured against the system time. During the measurement > of ~ 30 seconds I got a difference to the linux time (I just called > "watch -n 1 date" which should come from the mainboard system time, > doesn't it?) of ~10 seconds! This was the biggest difference I could > measure, sometimes it was a little bit less. Can you try kvm-85 with -rtc-td-hack option? kvm-84 added this option, from Gleb (CC'ed), to reinject lost RTC interrupts. > What's happening here? I reduced the io priority and the guest process > priority to a very low one - it didn't help! > > Oh - I'm running the stuff on an Intel Core2Duo T5600 @ 1.83GHz with 2 > Gig of RAM (Windows gets 1.5 Gig), the disk is an SATA with 40 Gigs. > > Best regards, > > Erik