maximizing CPU utilization

[sysadmin78]

Hi,

I am running VirtualBox 3.1.6 on Linux 64bit hosts AMD64 OS Ubuntu Server 10.4 LTS, quad core Xeon, previously on 32bit.

I have a Window 2003 server guest running, doing intense compilation. No matter what I do, I cannot get the best out of CPU performance as I did on same machine, but 32bit Linux OS - seems like some kind inefficient setting.

Which combination of settings would be best to maximize CPU performance on Windows guest?

- Enable VX-t... ?
- Enable Nested paging ?
- Enable Nested Paging ?
- IO APIC ?
- perhaps some kind of kernel optimization, CPU scheduler?

Thank you for any advice!

[sysadmin78]

I forgot to add that while monitoring CPU, I see 80-100% on Windows 2003 guest (1 vCPU), while on Linux 64bit hosts (using mpstat) I see only around 50% usage on one core, others are idle.
I am running only this virtual machine.

[sysadmin78]

Maybe I found out the problem. Is is not the Windows guest but running two guests that is the problem

I run one small dummy guest (32mb) that is paused, which is one kind of solution for high cpu usage when one (Windows) machine is idle. If I completely turn off this dummy paused guest machine, things get compiled in 10min, running one it takes an hour.

This is a quad core guest, though only one core is actually working.

Real question is here:
http://forums.virtualbox.org/viewtopic.php?f=7&t=35394