Comparative evaluation of latency tolerance techniques for software distributed shared memory

A key challenge in achieving high performance on software DSMs is overcoming their relatively large communication latencies. In this paper, we consider two techniques which address this problem: prefetching and multithreading. While previous studies have examined each of these techniques in isolation, this paper is the first to evaluate both techniques using a consistent hardware platform and set of applications, thereby allowing direct comparisons. In addition, this is the first study to consider combining prefetching and multithreading in a software DSM . We performed our experiments on real hardware using a full implementation of both techniques. Our experimental results demonstrate that both prefetching and multithreading result in significant performance improvements when applied individually. In addition, we observe that prefetching and multithreading can potentially complement each other by using prefetching to hide memory latency and multithreading to hide synchronization latency.