[vfio-users] VGA Passthrough limitations?

[Andrei Grigore]

I have passed the ignore msrs parameter but there is no change. I will
check with dmesg though. This happens in any game: WoW, SC2, HotS, D3 ...I
do not have anything besides Blizzard games to test this with, but I am
pretty sure is not game related.
On May 18, 2016 4:42 PM, "Quentin Deldycke" <quentindeldycke at gmail.com>
wrote:

> Easy to see, dmesg and you should have plently of flood about it :)
>
> --
> Deldycke Quentin
>
>
> On 18 May 2016 at 16:39, thibaut noah <thibaut.noah at gmail.com> wrote:
>
>> I'm thinking same thing as heroes of the storm, msrs spamming ?
>>
>> 2016-05-18 14:27 GMT+02:00 Andrei Grigore <andrei.grg at gmail.com>:
>>
>>> Dear all,
>>>
>>> I have this very strange issue that I can not understand:
>>>
>>> Everything works flawlessly or even better than bare metal. ...thing is,
>>> if I enable stereoscopic 3d vision (nvidia) in game, the performance drops
>>> to unplayable. The reason for that are CPU /RAM intensive elements such as
>>> view distances. Dropping other graphical elements to the lowest possible
>>> value makes no difference. This means that the GPU is not the bottleneck.
>>> Tested this on bare metal and i get around 50 fps with everything maxed
>>> out. With VGA passthrough I barely get 20. Disabling 3d vision boosts
>>> everything to 60 fps.
>>>
>>> The entire 3d vision sensor usb bus is passed through as well. I am
>>> running just this VM with 8/8 cores of a fx-8230 cpu with 12 gb of ram. The
>>> cpu is passed with host-passthrough. I am even using your latest patch and
>>> had enabled hyperv extensions with nvidia GPUs.
>>>
>>> The VM is installed clean with nothing but the games in it. As said
>>> using the same drivers on a bare metal windows works flawlessly.
>>>
>>> I cannot understand where the bottleneck is. CPU usage is not even close
>>> to 100%, plenty of ram left and not even 1MB of swap is made.
>>>
>>> I don't even know where to seek the problem. What can cause such a
>>> massive fps drop? Is there any bandtwidth limit that caps the 2x rendering
>>> needed for 3d vision?
>>>
>>> Many thanks,
>>> Andrei.
>>>
>>> _______________________________________________
>>> vfio-users mailing list
>>> vfio-users at redhat.com
>>> https://www.redhat.com/mailman/listinfo/vfio-users
>>>
>>>
>>
>> _______________________________________________
>> vfio-users mailing list
>> vfio-users at redhat.com
>> https://www.redhat.com/mailman/listinfo/vfio-users
>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/vfio-users/attachments/20160518/c98b2677/attachment.htm>