Mesa Preparing To Support Gallium Driver Specific DRIRC Tuning Options

We will likely be seeing more driver-specific per-application performance/workaround tuning within Mesa Gallium3D drivers moving forward.

Mesa DRIRC via driconf allows for per-application OpenGL workarounds and setting other bits that can help with performance for tunables that can help some games/applications but isn't suitable for globally enabling by default. Right now there isn't support for Gallium3D driver-specific tunables in DRIRC, but that is being changed by AMD developers.

Nicolai Hähnle of AMD has posted a set of 16 patches for allowing Gallium3D drivers to support driver-specific drirc options. Right now, for example, RadeonSI patches exist for hard-coding sisched for select applications (currently Superposition). Rather than needing to hard-code such "hacks" into Mesa, with these patches the sisched tunable can be easily set via drirc for specific applications.

This allowing of Gallium3D drivers to define and use their own configuration options will allow delivers to "provide some more opportunities for performance tuning", all about getting the best Linux gaming performance now that Mesa/Gallium3D drivers are nearly functionally-complete and there are just lots of little bits of optimizations left for squeezing more performance out of these drivers.

The Windows GPU drivers and binary Linux graphics drivers have long relied upon per-application/game profiles/settings for workarounds and obtaining maximum performance, but it's long been a controversial point among the open-source drivers.

This patch series will also make it possible for Gallium3D state trackers besides the OpenGL/Mesa state tracker to expose options too, such as for the Direct3D "Nine" state tracker.

More details via these 16 patches.