A Swap-based Cache Set Index Scheme to Leverage both Superpage and Page Coloring Optimizations

Abstract

We propose a novel cache set index scheme called SWAP (swap-based cache set index). SWAP introduces a pseudophysical address space that is used by the operating system. The real physical address used for cache and main memory access is obtained by simply swapping some of superpage number bits with cache set index bits from the pseudo-physical address. By adding a level of indirection to the physical memory management, we simultaneously support both page coloring and superpage optimizations. These work together to improve TLB and shared LLC performance with negligible cost. Our results show that SWAP can improve performance by an average of 15.1% (by up to 25.2%) compared to 7.34% and 8.26% for superpage and page coloring, respectively.