[Xen-users] Re: Windows and Multiple CPUS?

["Andrew Lyon" <andrew.lyon@xxxxxxxxx>]

On Fri, Sep 19, 2008 at 2:39 PM, Andrew Lyon <andrew.lyon@xxxxxxxxx> wrote:
> Hi,
>
> Am I correct in thinking that when Xen is running on a multi-core /
> smp system and several cpus are assigned to a VM they are "presented"
> as multiple single core cpus rather than 1 or more multi-core cpus?
>
> Microsoft CPU limits are for physical sockets, not cores.
>
> Windows XP and Vista are limited to two physical cpus, running under
> Xen the maximum cpus I have seen in task manager and system properties
> is 2, although device manager shows all of the assigned cpus (up to
> 8).
>
> Windows 2003 and 2008 standard edition are limited to 4 cpus, which is
> the limit I find under Xen, again device manager shows all assigned
> cpus (up to 8).
>
> Is there any way to make windows see the cpus as multi-core so that
> all 8 cores can be used ?
>
> Andy
>

I've also noticed that if I run "xm list" repeatedly as the VM is
starting up I can actually see the cpus being initialized, the value
matches the limit i find in windows:

A Windows 2003 R2 Standard Edition 32 Bit VM:

#grep vcpu Win2003x86.cfg
vcpus=8

xm list (several times during boot process)

Win2003x86                                  24  2048     1
Win2003x86                                  24  2048     2
Win2003x86                                  24  2048     3
Win2003x86                                  24  2048     4

But if i booted this version of windows on the raw hardware all 8 cpus
would be utilized.

Andy

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users