Heragu, Sampath C.

Caches are used in shared memory multiprocessors to reduce the effective memory latency, and network and memory bandwidth requirements. But the data spreading across the caches leads to the cache coherence problem. In this thesis, a new directory based cache coherence scheme, called the cache-vector protocol, is proposed and evaluated. The said scheme entails a low memory overhead but delivers a performance that is very close to that of the scheme proposed by Censier and Feautrier (3), which offers the best performance of all the directory based schemes. The performance of the cache-vector protocol is evaluated using trace-driven simulation. A figure of merit which takes into account the average memory latency, network traffic and the hardware overhead is introduced and used as the basis of comparison between the two schemes. The simulation results indicate that the cache-vector protocol is a viable solution to the cache coherence problem in large scale multiprocessors.