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

[Erik Rull <erik.rull@rdsoftware.de>]

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.

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