A write update cache coherence protocol for MIN-based multiprocessors with accessibility-based split caches

The authors present a cache coherence protocol for MIN-based multiprocessors with two distinct private caches: private-block caches containing information private to a processor and shared-block caches containing data accessible by all processors. The protocol utilizes a coherence control bus (snooping) for connecting all shared-block cache controllers. Timing problems due to variable transit delay through the MIN are dealt with by introducing transient states in the protocol. Assuming homogeneity of all nodes, a single-node queuing model is developed to analyze the system performance. This model is solved using the mean-value-analysis technique with protocol state probabilities, and few communication delays as input parameters. System performance measures are verified through simulation.