A Green & Open Christmas: GL 4.3 For Maxwell/Pascal, Huge Maxwell Performance Boost

There is some very exciting Nouveau news just ahead of Christmas if you are interested in this open-source NVIDIA driver on Maxwell graphics cards.

First up, Maxwell and Pascal graphics processors now have OpenGL 4.3 patches! Presently these newer NVIDIA GPUs on Nouveau are at OpenGL 4.1, but with three new patches from Samuel Pitoiset, he's enabling OpenGL 4.3. He explained in the series, "arb_shader_image_load_store-atomicity will most likely hang your box, I think it's now quite reasonable to enable GL 4.3
on Maxwell/Pascal GPUs. I suspect that test to be wrong because it doesn't even work on the NVIDIA blob. I have tested a bunch of benchmarks (UE4 demos) and real games like Shadow of Mordor and they all work fine."

Hopefully we see that OpenGL 4.3 enablement for Maxwell/Pascal in the Nouveau NVC0 Gallium3D driver in Mesa Git in short order.

Samuel Pitoiset's other Mesa patches are just as exciting if not more exciting. Being the "performance freak" that I am, this other patch series is like the best possible way to end a year for a Linux driver. Samuel has implemented scheduling control code to improve instruction pipelining on Maxwell GPUs. This NVC0 driver code makes use of new Maxwell control codes On a GeForce GTX 750 Ti as a test case, Samuel is seeing performance boosts from 53% all the way up to 259%. In many OpenGL test cases it's common to see over 200% performance improvements.

He had also explained, "On Maxwell, control codes are mainly used for setting the number of stall counts and for producing/consuming dependency barriers in order to avoid hazards...I think it's enough to understand the power of Maxwell control codes...Nouveau is still far away from the blob, but now I think Maxwell is actually in roughly the same shape as Kepler in terms of performance and features."

Great to see this latest work takes the NVC0 Gallium3D driver for putting Maxwell support closer to parity with the older Kepler GPUs.