The Gallium OpenSWR driver is a high performance, highly scalable software renderer targeted towards visualization workloads. For such geometry heavy workloads there is a considerable speedup over llvmpipe, which is to be expected as the geometry frontend of llvmpipe is single threaded.

This rasterizer is x86 specific and requires AVX or above. The driver fits into the gallium framework, and reuses gallivm for doing the TGSI to vectorized llvm-IR conversion of the shader kernels.

You can read more about OpenSWR on the project website.