The Impact of Synchronization and Granularity on Parallel Systems

In this paper, we study the impact of synchronization and granularity on the performance of parallel systems using an execution-driven simulation technique. We find that even though there can be a lot of parallelism at the fine grain level, synchronization and scheduling strategies determine the ultimate performance of the system. Loop-iteration level parallelism seems to be a more appropriate level when those factors are considered. We also study barrier synchronization and data synchronization at the loopiteration level and found both schemes are needed for a better performance