Improving disk cache hit-ratios through cache partitioning

An adaptive algorithm for managing fully associative cache memories shared by several identifiable processes is presented. The on-line algorithm extends an earlier model due to H.S. Stone et al. (1989) and partitions the cache storage in disjoint blocks whose sizes are determined by the locality of the processes accessing the cache. Simulation results of traces for 32-MB disk caches show a relative improvement in the overall and read hit-ratios in the range of 1% to 2% over those generated by a conventional least recently used replacement algorithm. The analysis of a queuing network model shows that such an increase in hit-ratio in a system with a heavy throughput of I/O requests can provide a significant decrease in disk response time