Accelerating cache coherence mechanism with speculation
Jun Ohno, Kei Hiraki · 2014
Directory is one of the common method to maintain cache coherence in multi/many-core systems. However, directory has problems in area, latency and complexity of protocol. Conversely, directoryless coherence mechanism, where each core invalidates its own L1 cache block (tear-off copy) is proposed. The problem of this method is that the cache blocks which are not written by another core are invalidated. We accelerate the coherence mechanism by speculatively executing with the value of these invalidated cache blocks. Our results show 2\% acceleration on average over derectory based MOESI protocol in 16 core system.