Sectored cache replacement algorithm for reducing memory writebacks

摘要

An improved sectored cache replacement algorithm is implemented via a method and computer program product. The method and computer program product select a cache sector among a plurality of cache sectors for replacement in a computer system. The method may comprise selecting a cache sector to be replaced that is not the most recently used and that has the least amount of modified data. In the case in which there is a tie among cache sectors, the sector to be replaced may be the sector among such cache sectors with the least amount of valid data. In the case in which there is still a tie among cache sectors, the sector to be replaced may be randomly selected among such cache sectors. Unlike conventional sectored cache replacement algorithms, the improved algorithm implemented by the method and computer program product accounts for both hit rate and bus utilization.

主权项

1. A method for selecting a cache sector among a plurality of cache sectors for replacement in a computer system, said method comprising:
determining a first set of cache sectors among said plurality of cache sectors excluding a most recently used cache sector, wherein each of said first set of cache sectors has the least amount of modified data among said plurality of cache sectors excluding said most recently used cache sector; upon determining that said first set of cache sectors comprises multiple cache sectors, determining a second set of cache sectors among said first set of cache sectors, wherein each of said second set of cache sectors has the least amount of valid data among said first set of cache sectors; and upon determining that said second set of cache sectors comprises multiple cache sectors, selecting a random cache sector among said second set of cache sectors for replacement.