[Fedora-xen] Unable to use multiple CPUs inside an HVM

[David Levinger]

You were 100% correct Andrew.  The problem was with how I configured XP,
though I seriously thought I knew better.  I sysprepped my image and redid
it with the "multi-processor" hal and voila I now see and utilize both
cores.  The odd part, however, is that the time required to complete a
processor intensive operation seems to remain almost the same.  Instead of
using 50% of the available host CPU it now using 100% but estimates only a
tem minute savings in processing time. Whaaaaat?

 

I still feel like I'm missing something rather important, but at least
both CPUs are now available for use.

 

d

 

  _____  

From: Andrew Cathrow [mailto:acathrow at redhat.com] 
Sent: Sunday, April 20, 2008 11:12 AM
To: David Levinger
Cc: fedora-xen at redhat.com
Subject: Re: [Fedora-xen] Unable to use multiple CPUs inside an HVM

 

When Windows installed selects the HAL library appropriate the the
hardware. If you install on a single CPU system then the uniprocessor HAL
is installed.
If you then add a second vcpu to the guest then the windows HAL won't see
it. 
You'll need to replace Window's hal. See links below for some background.
I don't think there is a Microsoft *supported* way to do this but I've
done this a number of times without issue on XP and 2000, but I've not
tried this on 2003, 2008 or Vista

http://support.microsoft.com/kb/309283/en-us
http://support.microsoft.com/default.aspx?scid=kb;EN-US;237556



On Sat, 2008-04-19 at 10:40 -0700, David Levinger wrote:



Hey Guys,

I have a fully virtualized XP guest that is set to have 2 VCPUs and in the
guest I see 2 CPUs but when it is under heavy load it only utilizes 1 of
the physical cores.

Both xm and virsh show that the guest only has 1 CPU, but my config file
and the guest show it should have 2.

What am I missing? How can I get this guest to have access to both cores?

Thanks!

David

 
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