A simple hardware prefetching scheme using sequentiality for shared-memory multiprocessors

Abstract

To reduce the memory access latency on shared-memory multiprocessors, several prefetching schemes have been proposed. The sequential prefetching scheme is a simple hardware-controlled scheme, which exploits the sequentiality of memory accesses to predict which blocks will be read in the near Future. Aggressive sequential prefetching prefetches many blocks on each miss to reduce the miss rates and results in good performance For application programs with high sequentiality. However, conservative sequential prefetching prefetches a few blocks on each miss to avoid prefetching of useless blocks, which shows better performance than aggressive sequential prefetching for application programs with low sequentiality. We analyze the relationship between the sequentiality of application programs and the effectiveness of sequential prefetching on various memory and network latency and propose a new adaptive sequential prefetching scheme. Simply adding a small table to the sequential prefetching scheme, the proposed scheme prefetches a large number of blocks for application programs with high sequentiality and reduces the miss rates significantly, and prefetches a small number of blocks for application programs with low sequentiality and avoids loading useless blocks.