RADV Lands "Big Page" Optimization For Navi 2

It's not clear if AMD has provided the independent RADV Vulkan driver developers at the likes of Valve, Red Hat, and Google with any Navi 2 hardware yet, but they do seem to be making progress on this open-source Radeon Vulkan driver separate from their official AMDVLK open-source driver.

Over the course of summer there was initial RADV support for Sienna Cichlid followed by Navy Flounder. Both these parts are unreleased GFX10.3 Radeon GPUs that appear to most definitely be Navi 2 at this point. That has been followed by work on bringing up ACO back-end support for GFX10.3 and other GFX10.3-specific work.

A few days ago what seems to be the first of likely more to follow GFX10.3-specific optimization work was introduced for Mesa 20.3-devel. RADV has added a "BIG_PAGE" optimization on GFX10.3 for helping to enhance the performance. The BIG_PAGE mode reduces traffic between the CB/DB/TCP blocks if the buffers respect a specific alignment. No performance numbers were shared as part of the change besides acknowledging it should help the performance.

The change is now in Mesa 20.3. The baseline for the forthcoming Navi 2 GPU support on Linux is the Linux 5.9 kernel, Mesa 20.2, and LLVM 11.0 (for the AMDGPU back-end with RadeonSI or optionally RADV), while building up into the latest development code-bases for these prominent components is this continued GFX10.3/Navi2 work. As usual, when it comes to new GPU support on Linux at launch, the newer the code generally equates to a more featureful and performant experience as well as generally addressing any initial show-stopping bugs.