engleski

An Adaptive Coherence Protocol Using Write Invalidate and Write Update Mechanisms

A number of different systems (multiprocessor systems, distributed systems, and nowadays Internet) replicate data (cache lines, pages, user defined data structures, and Internet objects) in order to improve the performance, but it introduces a coherence problem. Many different protocols have been introduced to maintain coherence between the copies of the same data item. The performance of such systems is very sensitive to the both data access behavior of the application and the coherence mechanism. Adaptive coherence protocols use a decision function to dynamically choose the appropriate coherence mechanism. The choice of coherence mechanism is determined from the data access behavior with the goal of improving performance. The decision function presented in this paper choose between a write invalidate and a write update mechanism, depending on which of these mechanisms incurs a lower cumulative communication coherence overhead. Simulation results are presented which demonstrated a significant improvement over other suggested solutions.

Cache coherence; replicated data; adaptive coherence protocol; decision function; memory access behavior; performance comparison

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