A scalable auto-tuning framework for compiler optimization

We describe a scalable and general-purpose framework for auto-tuning compiler-generated code. We combine Active Harmony´s parallel search backend with the CHiLL compiler transformation framework to generate in parallel a set of alternative implementations of computation kernels and automatically select the one with the best-performing implementation. The resulting system achieves performance of compiler-generated code comparable to the fully automated version of the ATLAS library for the tested kernels. Performance for various kernels is 1.4 to 3.6 times faster than the native Intel compiler without search. Our search algorithm simultaneously evaluates different combinations of compiler optimizations and converges to solutions in only a few tens of search-steps.