rusticl status update

Karol Herbst

September 28, 2026

What happened since last year?

Driver support

  • panfrost passed conformance, enabled by default
  • freedreno enabled by default

New features

  • OpenCL 3.1!
  • cl_ext_float_atomics
  • cl_khr_subgroup_extended_types
  • cl_khr_subgroup_ballot
  • cl_khr_subgroup_clustered_reduce
  • cl_khr_subgroup_non_uniform_arithmetic
  • cl_khr_subgroup_non_uniform_vote
  • cl_khr_subgroup_rotate

Performance

  • Queue Profiling done on the GPU
    • Speeds up darktables on freedreno a lot
  • Meta kernels:
    • buffer fills
  • Better workgroup size selection

mesa-libclc

  • Soft fork of upstream LLVM’s libclc
  • Contains bug fixes for conformance
  • Latest release based on llvm-22
  • Plan is to upstream fixes
  • LLVM release cycle makes us catch issues too late sometimes

Work in progress