SPECULATIVE EVALUATION FOR PARALLEL GRAPH REDUCTION

Speculative evaluation can improve the performance of parallel graph reduction systems through increased parallelism. Although speculation is costly, much of the burden can be absorbed by processors which would otherwise be idle. Despite the overhead required for speculative task management, our prototype implementation achieves 70% efficiency for speculative graph reduction, with little impact on mandatory tasks. Through speculative evaluation, some simple benchmarks exhibit nearly a factor of five speedup over their conservative counterparts.