Accelerating Data Movement on Future Chip Multi-Processors
Abstract
Moving data between cores on hardware coherent architectures suffers from memory latency and causes cache misses and o-herence traffic, which are obstacles to achieving high perform-ance. In this paper, we evaluate the potential for hardware opti-mization of message data transfer on chip multiprocessors with a combination of NAS parallel MPI benchmarks, Intel IMB MPI benchmarks, and a few microbenchmarks on a full-system simulator based on Simics and FeS2. We show that while pas-sive hardware driven by cores can reduce cache traffic, it pro-vides limited performance gains. We propose a data move-ment manager (DMM) that uses the on-chip coherence protocols to implement zero-copy message passing between separate ad-dress spaces and to remove synchronization and copy overheads from the processors. We also discuss methods for managing data placement in caches to reduce latency. We show that such a design shows substantial promise for both cache traffic reduc-tion and performance improvements.