More RADV Radeon Vulkan Optimizations Are In The Works

We are just one week into November and already there are a number of patches volleyed onto the mailing list for continuing to optimize the RADV open-source Radeon Vulkan driver.

Among the work that's been posted to the mailing list so far this month for the RADV Radeon Vulkan driver includes:

Prefetch VBO descriptors at the right place - Samuel Pitoiset of Valve posted this small patch today that yields a "minor boost" in performance for at least Serious Sam Fusion 2017 games and Dawn of War III.

Force enable LLVM sisched for The Talos Principle - Samuel also discovered that enabling the SI scheduler in LLVM when running The Talos Principle with RADV will help performance by about 4%. Though this patch is likely to be reworked as rather than hard-coding the application/game name, the developers would like this to be treated more DriConf-style of a whitelist in XML or similar for game-specific Vulkan optimizations.

Copy indirect lowering settings from radeonsi - Bas Nieuwenhuizen uncovered that when porting these settings over from RadeonSI, the tessellation Vulkan demo goes from ~4000 to ~4200 FPS.

Keep a stage mask per pipeline - This work by David Airlie should prevent some pointless loops from happening.

Free attachments on end command buffer - Not a performance optimization per se but a memory leak fix by David Airlie.

This is on top of various fixes and optimizations that already landed in Mesa Git this month, including copy descriptor support for handling the latest Dota 2 in Steam VR mode. This work is obviously too late for Mesa 17.3 but for those not riding Mesa Git will be found in Mesa 18.0 when it debuts as stable around February, which by then will be many more RADV optimizations for sure.