Quad core support for Windows XP guests

Discussions about using Windows guests in VirtualBox.
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azenz
Posts: 13
Joined: 7. Aug 2007, 09:20

Quad core support for Windows XP guests

Post by azenz »

I am about to buy a quad core system and wonder how many cores a Windows XP system running under Linux (kernel 2.6) can effectively use. If I run video encoding under the virtual XP, how many cores will be utilised (assuming the host system is mostly idle)? If quad core isn't used, will the system at least make use of two cores? Has Innotek run any benchmarks on this?

Really appreciate your answer as that's a really important issue for me. Thanks!

Adrian
steqve
Posts: 21
Joined: 18. Jun 2007, 11:28

Post by steqve »

A wild guess....but since vbox is scheduled as one process/thread it would only run at one core at the time.

Am I completely wrong here?
azenz
Posts: 13
Joined: 7. Aug 2007, 09:20

Post by azenz »

But the point is that multi-thread apps can make use of several cores even when doing one thing (that's what many video rendering apps can do now), so in theory Virtualbox could run a VM across several cores if it were programmed that way.
sandervl
Volunteer
Posts: 1064
Joined: 10. May 2007, 10:27
Primary OS: MS Windows Vista
VBox Version: PUEL
Guest OSses: Windows, Linux, Solaris

Post by sandervl »

There is only one thread that will run guest code for your VM. VirtualBox itself is very multi-threaded. Network, disk and other tasks run in separate threads.
azenz
Posts: 13
Joined: 7. Aug 2007, 09:20

Post by azenz »

Thanks for replying, does that mean that disk operations to virtual disks while running a virtual machine are on a different thread?

Are there any plans to make virtual machines themselves multi-threaded?
azenz
Posts: 13
Joined: 7. Aug 2007, 09:20

Post by azenz »

Oh, does Virtualbox support the Kentsfield Quad Core Virtualization Technology?
jetteroheller
Posts: 4
Joined: 9. Aug 2007, 21:30
Location: Portland, OR
Contact:

Post by jetteroheller »

It seems that the point of all this is that it doesn't. I've been trying to find out if anyone is going to enable such, but at this time it looks like there's no way to get VCPUs running on a guest OS.

My host is Fedora 7, and while I've had great luck with VirtualBox running Vista and Win2003 guests, it's for single-CPU only. For multiple CPUs, I have QEMU running other Linux guests on a F7 host, but have not successfully gotten a Windows guest to run. But in Qemu you can just select how many VCPU's you want to allocate to a guest, and if you have them available, you can use them.
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