Multiple Upcoming Games To Feature Optimized RADV “Radeon Vulkan” Support, Performance On Par With Windows

Multiple upcoming games are said to be receiving optimizations from the Mesa Radeon Vulkan driver (RADV), which is being worked on by Valve's Linux graphics development team. The optimizations are expected to offer similar performance as a user would find in a closed-source Windows operating system environment. In addition to optimizations, patchwork is also being integrated into this new game.

Samuel Pitoiset, Valve's Mesa developer, recently uploaded a patch that will fix stalling in specific "wait" packets, as outlined in the below text:

This is really noticeable for games that resolve a bunch of occlusion queries (in this case 4096) because it seems that emitting 4096 WAIT_REG_MEM packets can stall more than expected. Fixes this by waiting for queries in the resolve query shader.

This improves performance of an unreleased game by +~10% (71->78 FPS). RADV should now be really close to Windows performance for that title.

While the games are currently unknown and open to speculation, the amount of focus from Valve's Linux developers to ensure an impressive amount of optimizations being completed before the game's release is much higher than most other titles have seen, especially for optimizing for Steam Play and Proton.

Hans-Kristian Arntzen, the lead developer for implementing Direct3D 12 on Vulkan for Proton and Steam Play, also known as VKD3D-Proton, was mentioned in the merge request filed recently:

This removes the bubble with occlusion queries reported by Hans-Kristian and gives +~10% FPS in that game.

Mesa 23.2-devel also received a patch limiting the number of context rolls. The code radv: track DB_COUNT_CONTROL was uploaded to Mesa 23.2, with Pitoiset commenting,

This can be really noticeable for the BeginQuery/Draw/EndQuery pattern. It seems to improve a depth-only pass by +35% in one upcoming game because this removes a bunch of context rolls.

Michael Larabel of the Linux hardware site Phoronix mentioned that the timing of this implementation is most likely coinciding with the new game in development that has been receiving so much support recently. The merge request notes that "Hans-Kristian confirmed this specific pass no longer has context rolls. We did compare against native."

Mesa 23.2 will roll out in August and will have continued optimizations. Hopefully, we will find out the mystery title before then that is being optimized on both closed- and open-source channels, especially with Valve's backing and known partners that have assisted the group in the past. It is likely we will get more information about the games soon.

News Sources: Phoronix 1, 2, Mesa 1, 2