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

[Georg Bege <therion@ninth-art.de>]

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-------- Original-Nachricht --------
Betreff: 	Re: [Xen-devel] Fwd: Re: Xen 4.3 / 4.4 - concurrent APIs, VGA
Passthru
Datum: 	Sun, 03 Aug 2014 12:09:55 +0200
Von: 	Georg Bege <therion@ninth-art.de>
Antwort an: 	therion@ninth-art.de
An: 	Gordan Bobic <gordan@bobich.net>



Am 03.08.2014 11:49, schrieb Gordan Bobic:
> 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.    
See:
http://lists.xenproject.org/archives/html/xen-users/2013-09/msg00254.html

But now I came to the conclusion that I dont have the same issue with
Win7 at all (see last email).

>
>> 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 cant check, as states in the last email it must be about interrupts or
power saving states - it only happens when I pass in the GFX.
Without this the CPU is just idling on 0% inside the DomU.

>
>> 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.
Interesting information, thank you - if that is so then maybe Im still
hitting some other problems on WinXP as well - but I must say, Im
tinkering a lot so I have to re-verify this.
>
>> 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.
Ya maybe, as said Xen 4.3 isnt really working at all to me - as Im not
even able to passthru my GFX (err code 43) so I cannot even do the same
tests.

>
>> 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




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