Trying Out MESA_NO_ERROR / KHR_no_error Support On Mesa 17.2-dev

[droste]

At least Need For Speed Hot Pursuit (2010) is crashing and Burnout Paradise (though I would have to check to confirm this one).
But I just assumed that it was the games' fault.

Do you think there will be cpu gains with this extension eventually?
I admit I was surprised to see identical performance in Feral games because I expected it would relieve the cpu, if only a little bit.
Hitman, in particular, is in dire need for anything that could improve its cpu bottleneck

As soon as every GL function has a "no error" variant in the source code this should cause less load on the CPU. Right now if you enable this only some functions actually skip the validation. The function that don't skip the validation will just not report the error. So nothing is gained here. But Samuel Pitoiset and Timothy Arceri are actively adding more functions with a "no error" code path which actually skips the validation.

This file contains the GL entry points:

https://cgit.freedesktop.org/mesa/mesa/tree/src/mapi/glapi/gen/gl_API.xml

Only functions with the following have a "no error" code path:

<function name="..." no_error="true" ...>

For example this series add some "no error" implementations:

https://lists.freedesktop.org/archives/mesa-dev/2017-May/155584.html

[Tomin]

Do you think there will be cpu gains with this extension eventually?
I admit I was surprised to see identical performance in Feral games because I expected it would relieve the cpu, if only a little bit.

I think they've only removed the checks that are easiest to remove and there is more work to do to actually gain anything from this.

[gurv]

As soon as every GL function has a "no error" variant in the source code this should cause less load on the CPU. Right now if you enable this only some functions actually skip the validation. The function that don't skip the validation will just not report the error. So nothing is gained here. But Samuel Pitoiset and Timothy Arceri are actively adding more functions with a "no error" code path which actually skips the validation.

This file contains the GL entry points:

https://cgit.freedesktop.org/mesa/mesa/tree/src/mapi/glapi/gen/gl_API.xml

Only functions with the following have a "no error" code path:

<function name="..." no_error="true" ...>

For example this series add some "no error" implementations:
https://lists.freedesktop.org/archiv...ay/155584.html

Thank you and Tomin for these informations, I hadn't realized this new functionality was only starting being developed.
So it makes sense that I didn't see much difference yet.
Now I'm excited for the possible improvements down the road