Re: Fwd: Re: Xen 4.3 / 4.4 - concurrent APIs, VGA Passthru

[Gordan Bobic <gordan@bobich.net>]

On 08/02/2014 11:49 AM, Georg Bege wrote:
> Hello again
>
> Well so far I can now tell, I tested it on WinXP x64 quite a lot
> - most things are working.
> Including AAA games like Witcher 2, I didnt try a very memory consuming
> game yet.
> But I dont really think that I have the same bug you are refering to -
> in WinXP x64 the /PATCHTPR boot flag did help greatly, it really boosted
> the performance to near native.

What does this flag do? Googling for it found no results.

> I dont think I encountered any memory usage, used like applications
> consuming the first 4GB of the DomU.

I am inclined to agree, you aren't hitting the same problem.

> Im trying to figure what to do for Windows 7, its working good too -
> even with VGA Passthrough,
> but its almost always consuming 33%-80% CPU usage for no reason...

Can you check from within the domU which process is eating CPU? Or are 
you saying that with Windows 7 inside your domU task manager is showing 
0% CPU usage but xentop is showing 33-80% CPU usage?

> I also stumpled upon the issue that if you reboot a VGA Passthru DomU
> then that the GFX adapter looses performance (which was explained
> somewhere in the docs already).

That is _very_ wrong. That only happens on ATI GPUs, I have never seen 
that happen with an Nvidia GPU.

> Atm. all this is done with Xen 4.4 - Im not sure why I would go back to
> Xen 4.3, Xen is improving greatly over each version I think, that older
> versions have more (unfixed) issues is quite logical.

IMO that doesn't follow for any software. More feature doesn't mean 
fewer bugs, usually the opposite.

> I just wonder what I can do for Win7 performance wise so that I can test
> things like Borderlands 2 you referred to... or any other high memory
> usage application.

Borderlands 2 runs under XP64 just fine. I'm not sure what else to 
suggest, I rebuilt one of my two XP64 VMs to Win7 x64 the other day 
relatively painlessly. Same config, just different disk image. No 
problems so far.

Gordan