Patent attributes
Aspects of the invention relate to improvements to the Least Recently Used (LRU) cache replacement method. Weighted LRU (WLRU) and Compact Weighted LRU (CWLRU) are CPU cache replacement methods that have superior hit rates to LRU replacement for programs with poor locality, such as network protocols and applications. WLRU assigns weights to cache lines and makes replacement decision by comparing weights. When a cache line is first brought into the cache, it is assigned an initial weight. Weights of cache lines in WLRU increase when hit and decrease when not hit. Weights in WLRU also have upper limits, and the weight of a cache line never increases beyond the upper limit. CWLRU is a more space-efficient implementation of WLRU. Compared to WLRU, CWLRU uses fewer bits per cache line to store the weight.
