RADV Driver Lands Another Optimization: "Missing In RADV For A Very Long Time"
A four year old optimization idea for the RADV driver was scratched off the TODO list last week for next quarter's Mesa 26.1 release.
Opened back in May 2022 was this ticket by Timur Kristof of Valve's Linux graphics team:
After no major work on it until a week ago, Samuel Pitoiset -- also of Valve's Linux graphics team -- has ported the optimization over to the RADV Vulkan driver.
This code was merged last week for Mesa 26.1 RADV to optimize the clipping performance with PA_SU_HARDWARE_SCREEN_OFFSET.
The PA_SU_HARDWARE_SCREEN_OFFSET register has been found on AMD GPUs for at least 16+ years and making use of it should help with clipping performance. No specific performance numbers were shared though as part of either the issue tracker or merge request.
Opened back in May 2022 was this ticket by Timur Kristof of Valve's Linux graphics team:
"radv: Port si_emit_guardband to RADV
Setting PA_SU_HARDWARE_SCREEN_OFFSET properly (like RadeonSI does) should improve clipping (not culling) performance."
After no major work on it until a week ago, Samuel Pitoiset -- also of Valve's Linux graphics team -- has ported the optimization over to the RADV Vulkan driver.
👁 RADV long time optimization merged
This code was merged last week for Mesa 26.1 RADV to optimize the clipping performance with PA_SU_HARDWARE_SCREEN_OFFSET.
👁 PA_SU_HARDWARE_SCREEN_OFFSET documentation
The PA_SU_HARDWARE_SCREEN_OFFSET register has been found on AMD GPUs for at least 16+ years and making use of it should help with clipping performance. No specific performance numbers were shared though as part of either the issue tracker or merge request.