Going the distance for TLB prefetching: an application-driven study

The importance of the translation lookaside buffer (TLB) on system performance is well known. There is a large body of literature on prefetching for caches, and it is not clear how they can be adapted (or if the issues are different) for TLBs, how well suited they are for TLB prefetching, and how they compare with the recency prefetching mechanism. This paper presents the first detailed comparison of different prefetching mechanisms (previously proposed for caches) - arbitrary stride prefetching and Markov prefetching -for TLB entries, and evaluates their pros and cons. In addition, this paper proposes a novel prefetching mechanism, called distance prefetching, that attempts to capture patterns in the reference behavior in a smaller space than earlier proposals. Using detailed simulations of a wide variety of applications (56 in all) from different benchmark suites and all the, SPEC CPU2000 applications, this paper demonstrates the benefits of distance prefetching.