MAINTAINING CACHE COHERENCE THROUGH COMPILER-DIRECTED DATA PREFETCHING

In this paper, we propose a compiler-directed cache coherence scheme w hich makes use of data prefetching to enforce cache coherence in large -scale distributed shared-memory (DSM) systems. The Cache Coherence Wi th Data Prefetching (CCDP) scheme uses compiler analyses to identify p otentially stale and nonstale data references in a parallel program an d enforces cache coherence by prefetching the potentially stale refere nces. In this manner, the CCDP scheme brings up-to-date data into the caches to avoid stale references and also hides the latency of these m emory accesses. Furthermore, the scheme also prefetches the nonstale r eferences to hide their memory latencies. To evaluate the performance impact of the CCDP scheme on a real system, we applied the scheme on f ive applications from the SPEC CFP95 and CFP92 benchmark suites, and e xecuted the resulting codes on the Gray T3D. The experimental results indicate that for all of the applications studied; our scheme provides significant performance improvements by caching shared data and using data prefetching to enforce cache coherence and to hide memory latenc y. (C) 1998 Academic Press, Inc.