Research on the Scalability of Directory-Based Cache Coherence

The DSM multiprocessors systems that employ the cache coherence non-uniform memory access architecture is one of the implementation ways of recent massively high-performance parallel computers.Because of the better scalability than snooping protocols, directory protocols are widely used.With the expansion of system size , the directory protocols also encounter the problem of scalability. First, the factors that affect the scalability of directory protocols are analyzed, several typical directory organization schemes are discussed. Finally, we propose a two-level directory scheme based on directory cache.