Per-node multithreading and remote latency

This paper evaluates the use of per-node multithreading to hide remote memory and synchronization latencies in software DSMs. As with hardware systems, multithreading in software systems can be used to reduce the costs of remote requests by running other threads when the current thread blocks. We added multithreading to the CVM software DSM and evaluated its impact on the performance of a suite of common shared memory programs. Multithreading resulted in speed improvements of at least 20 percent in two of the applications, and better than 15 percent for several other applications. However, we also found that good performance cannot always be achieved transparently for nontrivial applications. Also, the characteristics of the underlying DSM protocol can have a large effect on multithreading's utility.