An evaluation of DELTA, a decoupled pre-fetching virtual shared memory system

Decoupled pre-fetching is a technique for reducing the page miss overheads in Distributed Shared Memory systems by separating out those instructions responsible for data fetching from the main instruction stream and running them on a separate CPU whose function is to predict store accesses ahead of time. This approach differs from other pre-fetching approaches in that the predictions of data usage are obtained dynamically from partial evaluation of the program and this promises to produce considerably better performance in circumstances where the access patterns are non-regular and cannot be extracted by static analysis of the program. This paper reviews the techniques of decoupled pre-fetching with particular emphasis on Cache only Memory Architectures (COMA). It then presents a more thorough evaluation of the ideas than has previously been attempted using some of the SPLASH benchmarks. It is shown that the techniques perform well on some programs but that, as expected, the benefits of pre-fetching are negated when there is a high rate of data invalidation caused by global updating