Timer hickups on XP Guest

Dtag · Post by **Dtag** » 17. Dec 2007, 16:25

Hi
I am running XP as guest on a Ubuntu 7.10 Host machine. Unfortunately I am experiencing some problems recently concerning timing on the Windows machine. It seems like the time was having hick-ups on the XP machine. So Time runs normally for a while, suddenly it gets stuck for a few seconds, and then runs quicker than usual to catch up again. This problem is visible for all timing related things on the machine, even cursor blinking or the windows clock. I believe it may be related to the process priority on my Linux host - I tried using renice to increase the priority but for some reason it didn't have any effect.
Any ideas?
Thanks alot in advance

Post by **frank** » 4. Jan 2008, 11:08

Try to add the parameter 'nohz=off' to the kernel command line of your Ubuntu host. Note that you have to add this parameter to the 'kopt' line in /boot/grub/menu.lst. Don't forget to execute update-grub after changing the menu.lst file.

Does this kernel parameter makes any difference?

Dtag · Post by **Dtag** » 22. Jan 2008, 22:39

Hi
thanks for the reply, and sorry for my late rereply

... I added the parameter to this line:
# kopt=root=UUID=aac93673-9bfd-4bce-b4b5-7d3b3fb3446d ro nohz=off

And then executed update-grub which appeared to modify the boot.lst further by adding that nohz=off to other lines as well. Correct I guess.

While the timing does appear to behave a bit differently, the clock is still not ticking correctly inside my VM

Any other ideas?

Post by **frank** » 28. Mar 2008, 11:34

Please use the new vboxdrv kernel parameter 'force_async_tsc=1' which was introduced in VirtualBox 1.5.6. Have a look at

http://vbox.innotek.de/pipermail/vbox-u ... 03017.html