A Hybrid Static-Dynamic Classification for Dual-Consistency Cache Coherence

作者：Ros Alberto^*; Jimborean Alexandra

来源：IEEE Transactions on Parallel and Distributed Systems, 2016, 27(11): 3101-3115.

DOI：10.1109/TPDS.2016.2528241

• Multiprocessors
• cache coherence
• classification of accesses
• runtime
• compiler
• consistency model
• data races

Traditional cache coherence protocols manage all memory accesses equally and ensure the strongest memory model, namely, sequential consistency. Recent cache coherence protocols based on self-invalidation advocate for the model sequential consistency for data-race-free, which enables powerful optimizations for race-free code. However, for racy code these cache coherence protocols provide sub-optimal performance compared to traditional protocols. This paper proposes SPEL++, a dual-consistency cache coherence protocol that supports two execution modes: a traditional sequential-consistent protocol and a protocol that provides weak consistency (or sequential consistency for data-race-free). SPEL++ exploits a static-dynamic hybrid classification of memory accesses based on (i) a compile-time identification of extended data-race-free code regions for OpenMP applications and (ii) a runtime classification of accesses based on the operating system's memory page management. By executing racy code under the sequential-consistent protocol and race-free code under the cache coherence protocol that provides sequential consistency for data-race-free, the end result is an efficient execution of the applications while still providing sequential consistency. Compared to a traditional protocol, we show improvements in performance from 19 to 38 percent and reductions in energy consumption from 47 to 53 percent, on average for different benchmark suites, on a 64-core chip multiprocessor.

• 出版日期2016-11-1