Not Quite My Tempo: Matching Prefetches to Memory Access Times

Modern prefetchers can generally be divided into two categories, spatial and temporal, based on the type of correlations they at-tempt to exploit. Although these two types have different advan-tages, and perform well on different application sets, a design that utilizes both types of information will be able to achieve greater prefetch accuracy. We address the lack of temporal information in the state-of-the-art Spatial Memory Streaming (SMS) prefetcher by proposing Tempo, a novel banked implementation of SMS that fur-ther classifies cache accesses within the same physical page based on the repetitive miss latency, or tempo, present in the local ac-cess stream. Evaluated on the SPEC CPU2006 benchmark suite, Tempo reduces useless prefetches by 17.6%, and achieves 1.45% and 2.57 % increase in IPC on high and low bandwidth memory configurations over a purely spatial SMS design. 1