A comparison of compiler tiling algorithms

Abstract

Linear algebra codes contain data locality which can be exploited by tiling multiple loop nests. Several approaches to tiling have been suggested for avoiding conflict misses in low associativity caches.We propose a new technique based on intra-variable padding and compare its performance with existing techniques. Results show padding improves performance of matrix multiply by over 100% in some cases over a range of matrix sizes. Comparing the efficacy of different tiling algorithms, we discover rectangular tiles are slightly more efficient than square tiles. Overall, tiling improves performance from 0-250%. Copying tiles at run time proves to be quite effective.