Re: kvm-77 Excessive Disk Access causes real time clock hang!

[Marcelo Tosatti <mtosatti@redhat.com>]

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