Open-Source Radeon Vulkan Driver Improvement Scores Huge Ray-Tracing Wins

A change merged today for Mesa 24.0 is yielding much better Vulkan ray-tracing performance for the Radeon Vulkan driver "RADV" across a number of games.

The change by developer Friedrich Vock has been in the works the past two months and is about converting 1D ray launches to 2D. Due to unaligned dispatches, 1D launches only use eight threads per wave while converting them to 2D significantly increases occupancy.

With this change affecting just around 100 lines of code to RADV and the AMD ACO compiler, there is around a 30% performance boost to the game Ghostwhire Tokyo.

In the comments to the MR are even more fascinating metrics. Adriano Martins tested out the change on a Radeon RX 6700 XT ands found 10~75% better performance for various ray-traced games. Hellblade: Senua's Sacrifice, The Witcher 3: Wild Hunt, Sackboy: A Big Adventure, and others all scored nice wins with this RT improvement.

Adam Niederer also tested this change when using a Radeon RX 7900 XT and found improvements up to 140~200% in games like Chrous and big wins too for Ghostwire: Tokyo and The Witcher 3.

Real nice RADV ray-tracing wins for Mesa 24.0 that should be out as stable around the end of February and in turn also make it into the likes of Ubuntu 24.04 LTS and Fedora 40 this spring. The RADV ray-tracing performance has sure come a long way over the past two years.