Synchronization optimizations for efficient execution on multi-cores

摘要

Multi-cores are becoming ubiquitous as exemplified by Sun's Niagra-2, Intel's Nehalem and AMD's Sau Paulo octal cores. The number of cores per chip is expected to rise in foreseeable future, as evidenced by the recently announced Intel's 80-core Teraflops Research Chip. Exploiting the parallelism of multicores necessitates concurrent software. One way to parallelize programs, not amenable to auto-parallelization, is via explicit synchronization. The placement of the synchronization primitives has a large bearing on how much thread-level parallelism (TLP) can be achieved. In this paper, we propose novel predication-based and other adjunct synchronization optimizations which facilitate exploitation on higher level of TLP than what can be achieved using the state-of-the-art. We demonstrate the efficacy of our techniques, on a real machine, using real codes, specifically, from the industry-standard SPEC CPU benchmarks and other widely used open source codes such as PostgreSQL. Our results show thatthe proposed techniques yield significantly higher levels of TLP than the state-of-the-art.