Radeon RADV Driver Enables Displayable DCC For Some Performance Benefit

The open-source Mesa Radeon Vulkan driver "RADV" has now enabled displayable DCC (Delta Color Compression) support that should yield some performance benefit while there still is more work to be completed.

Google engineer and RADV co-founder Bas Nieuwenhuizen has merged the displayable DCC support into this open-source Radeon Vulkan driver. Delta Color Compression can help with video memory bandwidth savings for both dGPUs and APUs by basically storing pixel differences within a block as a delta relative to one pixel at full precision per block, which often times c can mean measurable bandwidth savings and in turn greater performance.

The RadeonSI driver for some time has supported displayable DCC within that open-source AMD OpenGL driver while now the initial support has been flipped on for the RADV Vulkan code.

Bas noted in the merge request that with this initial support it "generally has a small speedup or same perf" in the testing thus far. The code still needs to be adapted with buffer modifier support, optimized re-tiling/re-tile memory management, and less overhead around overlays.

This improvement will be found in Mesa 21.1 due out in Q2.