Latest Round Of Optimizations Wrap Up For Old ATI R300 To R500 GPUs On Linux

Last week I wrote about Mesa's R300 Gallium3D driver seeing new optimizations for R300~R500 class GPUs from the ATI days, thanks to the open-source community. Another merge request is now open that finishes up the latest optimization spree for these old pre-AMD GPUs on Linux.

Independent Mesa contributor Pavel Ondračka has been working on some R300 shader optimizations and on Sunday opened up his latest merge request that completes the optimization work he set out to achieve. It stems from an issue raised several months prior around possibly merging ADD and MUL instructions into MAD when effectively only two sources are used.

Old ATI/AMD GPUs continue seeing driver improvements on Linux thanks to the open-source code and passionate community developers.

The latest MR adds MOV+MAD handling and other small tweaks. On top of the prior work, the latest R300g optimizations do help a bit on a ShaderDB run with slight reductions to the generated instruction count:

total instructions in shared programs: 136382 -> 135151 (-0.90%)
instructions in affected programs: 52418 -> 51187 (-2.35%)
total temps in shared programs: 18939 -> 18926 (-0.07%)
temps in affected programs: 641 -> 628 (-2.03%)

The R300 Gallium3D driver covers from ATI R300 up through R500 (Radeon X1000 series) GPUs on Linux. Though if you are still relying on the R300g driver for day-to-day use on Linux in 2022, you ought to really consider upgrading soon for a far faster, more featureful, and much greater power efficiency with today's modern hardware.