In certain workloads, OpenSWR has the potential of being much faster than Gallium3D's LLVMpipe driver. With today's work, there are more optimizations and other enhancements for handling the OpenGL graphics workload on the CPU.
As of today in mainline Mesa is support for OpenSWR using the latest LLVM SVN (v3.9) development code, NUMA optimizations, arena optimizations, and more than 50 other commits. The rasterizer backend code was also reorganized along with other changes.
Those utilizing OpenSWR and wanting to learn more can check out the latest Mesa Git code.