Xen users - Aug 2009 - Windows 2000 server VM on Xen open source CPU hog?

Hi,

I''m running a Windows 2000 server and a Windows 2003 server as guests
on
a Linux dom0.
Windows 2000 server seems to hog the CPU (constant at 200%, ie. using
two CPUs) according to xentop.
Windows 2003 uses virtually no CPU.

Any ideas how I can fix this?

best,
Jan


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

> Hi,
> 
> I''m running a Windows 2000 server and a Windows 2003 server as
guests
on
> a Linux dom0.
> Windows 2000 server seems to hog the CPU (constant at 200%, ie. using
> two CPUs) according to xentop.
> Windows 2003 uses virtually no CPU.
> 
> Any ideas how I can fix this?
> 
What does Windows 2000 report it''s CPU usage at?

Does the problem appear with only a single CPU (and preferably a UP
HAL)?

GPLPV (which doesn''t work on W2K) has an option to patch windows
kernels
< W2K3SP2 to improve performance. Backporting just that part might not
be a huge deal, although the problem that fixes wouldn''t cause 2
cpu''s
to be pegged at 100%...

James

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

Hi James,
> What does Windows 2000 report it''s CPU usage at?
>   
Below 10% when xentop consistently reports 190-199.5%.
> Does the problem appear with only a single CPU (and preferably a UP
> HAL)?
>   
I haven''t tried that yet. The server used to run on physical hardware
so
anything that was on it was migrated to the VM. I noticed there are two
(?) HALs registered: ACPI Multiprocessor PC and MPS Multiprocessor PC...
> GPLPV (which doesn''t work on W2K) has an option to patch windows
kernels
> < W2K3SP2 to improve performance. Backporting just that part might not
> be a huge deal, although the problem that fixes wouldn''t cause 2
cpu''s
> to be pegged at 100%...
>   
I had a look at GPLPV but quickly realised Windows 2000 wasn''t
supported...

Jan


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

On Thu, Aug 27, 2009 at 10:21 AM, Jan Bakuwel<jan.bakuwel@gmail.com>
wrote:
>> GPLPV (which doesn''t work on W2K) has an option to patch
windows kernels
>> < W2K3SP2 to improve performance. Backporting just that part might
not
>> be a huge deal, although the problem that fixes wouldn''t cause
2 cpu''s
>> to be pegged at 100%...
>>
>
> I had a look at GPLPV but quickly realised Windows 2000 wasn''t
supported...
James, if I remember correctly, you mentioned something about newer
Xen version or Intel CPUs emulating the TPR register.
Would upgrading to (say) Xen 3.4 help reduce CPU load on vanilla
Win2000 under Xen?

-- 
Fajar

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

> >
> > I had a look at GPLPV but quickly realised Windows 2000
wasn''t
supported...
> 
> James, if I remember correctly, you mentioned something about newer
> Xen version or Intel CPUs emulating the TPR register.
> Would upgrading to (say) Xen 3.4 help reduce CPU load on vanilla
> Win2000 under Xen?
> 
I''m not sure exactly where that support got to and how it compares to
the no-tpr optimisations that Microsoft made in 2003sp2.

It wouldn''t peg the cpu''s at 200% though - I suspect the
problem lies
elsewhere, although the tpr issue may be adding to it.

James

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

I ran into the same problem with Citrix''s commercial product.

We saw the same thing as you, CPU usage was reported very high when the
processors were pretty much idle in windows.  When there was load in
windows, the usage in xentop dropped, as if it was the inverse of the
real usage.  This is only true with the multiproc hal.

After lots and lots of searching, I found the following KB that resolved
the issue:
http://support.microsoft.com/default.aspx?scid=kb;EN-US;919521

Unfortunately, it was a while ago that I dealt with this issue so I
don''t remember all the details, but I think it has something to do with
the way windows 2000 multiproc hal idles the cpus.  With the above
registry setting, it idle''s at 0% ,as reported in xentop.

Let me know if this setting solves your problem too.

Doug Magee

-----Original Message-----
From: xen-users-bounces@lists.xensource.com
[mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Jan Bakuwel
Sent: Wednesday, August 26, 2009 11:21 PM
To: James Harper
Cc: xen-users@lists.xensource.com
Subject: Re: [Xen-users] Windows 2000 server VM on Xen open source CPU
hog?

Hi James,
> What does Windows 2000 report it''s CPU usage at?
>   
Below 10% when xentop consistently reports 190-199.5%.
> Does the problem appear with only a single CPU (and preferably a UP
> HAL)?
>   
I haven''t tried that yet. The server used to run on physical hardware
so
anything that was on it was migrated to the VM. I noticed there are two
(?) HALs registered: ACPI Multiprocessor PC and MPS Multiprocessor PC...
> GPLPV (which doesn''t work on W2K) has an option to patch windows
kernels
> < W2K3SP2 to improve performance. Backporting just that part might not
> be a huge deal, although the problem that fixes wouldn''t cause 2
cpu''s
> to be pegged at 100%...
>   
I had a look at GPLPV but quickly realised Windows 2000 wasn''t
supported...

Jan


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

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