Study on Distributing Pattern of Shared Data in CC-NUMA System

Nowadays, directory-based cache coherence protocols have been the best choice in designing large-scaled CC-NUMA systems. Directory contains the shared information of all memory blocks in system. The number of copies of shared data in system and their distributing characteristics are deeply influenced by the characteristics of application programs. In this paper, a Markov chains model is built for the distributing pattern of shared data in CC-NUMA systems. It's proved that, the average number of cache copies of shared data is small in CC-NUMA systems. Especially, when the percentage of shared read operations in applications is lower than 80%, this number is less than 5.