Improving performance of OpenMP for SMP clusters through overlapped page migrations

Costly page migration is a major obstacle to integrating OpenMP and page-based software distributed shared memory (SDSM) to realize the easy-touse programming paradigm for SMP clusters. To reduce the impact of the page migration overhead on the execution time of an application, the previous researches have mainly focused on reducing the number of page migrations and hiding the page migration overhead by overlapping computation and communication. We propose the 'collective-prefetch' technique, which overlaps page migrations themselves even when the prior approach cannot be effectively applied. Experiments with a communication-intensive application show that our technique reduces the page migration overhead significantly, and the overall execution time was reduced to 57%∼79%.