X Presentation and Synchronization - will it help Wine performance

[Roderick Colenbrander]

On Tue, Aug 10, 2010 at 6:53 AM, Henri Verbeet <hverbeet at gmail.com> wrote:
> On 10 August 2010 15:27, Groeschel, Volker <volker.groeschel at sap.com> wrote:
>> I wonder if Wine will profit from the new X Presentation and Synchronization
>> feature NVIDIA is working on:
>>
>>
>>
>> http://people.freedesktop.org/~aplattner/x-presentation-and-synchronization.pdf
>>
> I doubt it, unless it will somehow make the drivers themselves faster.
>
>> e.g. when I start several instances of my game with Wine on my computer (AMD
>> X2 with Ubuntu and proprietary NVIDIA graphic drivers), performance  breaks
>> down dramatically.
>>
> Yeah, that's a fairly well known issue with the nvidia drivers, you
> can also see that when e.g. comparing fps from running two glxgears
> instances with running just a single instance. Running two instances
> at the same time will get you much less than half the performance.
> That issue may be unique to nvidia's setup, I don't get it with the
> free r600 driver. Though it should be said that performance there
> isn't quite at the level where it's fair to compare yet.
>
>
>

In my experience on Nvidia Fermi hardware performance scales linearly
at least in modern shader limited applications like the Heaven
benchmark. In four instances at relatively heavy settings, (I believe
each was running at 1024x768 or higher) the fps is fps/4 and by adding
each window I saw a linear drop.

I don't remember for sure but I think I saw the same on games on Wine,
though I would have to recheck it. Older non-Fermi hardware didn't
seem to scale as well, but I haven't done that much testing on those
GPUs.

Yesterday I talked with Nvidia guys and they also said that typically
performance should scale linearly but there can be exceptions in which
some things might be time sliced.

I might be able to do some more testing and if it shows anything
interesting I will reply here.

Roderick