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Re: [Xen-users] SOLVED - Poor Windows 2003 + GPLPV performance compared to VMWare

On 19/09/12 23:00, James Harper wrote:
>> On Wed, 2012-09-19 at 13:19 +0100, Adam Goryachev wrote:
>>> On 19/09/12 19:43, Adam Goryachev wrote:
>>>> I've updated to SP2, and will re-test in the next few hours,
>>> Excellent news, the issue is completely resolved, and in fact,
>>> performance is now better than vmware, and better than the old
>>> original physical box pre-virtualisation. The entire task now
>>> completed in 30 minutes, the previous best was 40 minutes (ie, prior to
>> xen).
>> Excellent news!
>> James, since you suggested it, do you happen to know what it is about
>> pre-SP2 W2K3 that is so bad? Do those versions beat on the TPR or
>> something else?
>> (Just curious)
> Yes it will almost certainly be TPR access. I actually thought MS made the 
> change in SP1 but maybe it was SP2 (don't know if the OP upgraded from RTM to 
> sp2 or sp1 to sp2, but quite possibly I just don't remember :)
Nope, definitely had SP1, and installed SP2 to get the performance boost
(massive performance boost).
> The change they made means that the TPR doesn't get touched at all anymore, 
> so is much faster.
> For prior versions (and XP and 2000), GPLPV can patch AMD systems to use the 
> CR8 (I think) registr for TPR access which is much faster. For Intel, the 
> best I could do was cache TPR so that reads were fast... it's still quite a 
> speedup. 
Am running this on AMD, with the GPLPV drivers, so I guess something
isn't working right with that optimisation...

Specifically, using the AMD Phenom(tm) II X6 1100T Processor
Perhaps this processor doesn't have the CR8 register, maybe an opteron
is needed or something?
> I thought Xen optimised this for Intel though and my patching wasn't 
> necessary anymore? Or maybe the OP is running a version of xen that doesn't 
> have that feature??
So Xen is patched only for Intel, and therefore I missed out again since
I am on AMD, or my xen doesn't have this feature.
xen_major              : 4
xen_minor              : 1
xen_extra              : .3

All software is Debian Testing current.

Sure, I'd be happy to get additional performance from further tuning,
but I'm seriously happy at this stage of things... Now all I need to do
is get a modem working with a serial port over ethernet device.... That
I'll leave to another day/thread :)


Adam Goryachev
Website Managers
Ph: +61 2 8304 0000                            adam@xxxxxxxxxxxxxxxxxxxxxx
Fax: +61 2 8304 0001                            www.websitemanagers.com.au

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