Optimizing Matrix Multiply using PHiPAC: a Portable, High-Performance, ANSI C Coding Methodology

Modern microprocessors can achieve high performance on linear algebra kernels but this currently requires extensive machine-specific hand tuning. We have developed a methodology whereby near-peak performance on a wide range of systems can be achieved automatically for such routines. First, by analyzing current machines and C compilers, we've developed guidelines for writing Portable, High-Performance, ANSI C (PHiPAC, pronounced "fee-pack"). Second, rather than code by hand, we produce parameterized code generators. Third, we write search scripts that find the best parameters for a given system. We report on a BLAS GEMM compatible multi-level cache-blocked matrix multiply generator which produces code that achieves around 90% of peak on the Sparcstation-20/61, IBM RS/6000-590, HP 712/80i, SGI Power Challenge R8k, and SGI Octane R10k, and over 80% of peak on the SGI Indigo R4k. The resulting routines are competitive with vendoroptimized BLAS GEMMs. CS Division, University of Californi..