Computer caching methods and apparatus

Abstract

When cache misses occur simultaneously on two or more ports of a multi-port cache, different replacement sets are selected for different ports. The replacements are performed simultaneously through different write ports. In some embodiments, every set has its own write ports. The tag memory of every set has its own write port. In addition, the tag memory of every set has several read ports, one read port for every port of the cache. For every cache entry, a tree data structure is provided to implement a tree replacement policy (for example, a tree LRU replacement policy). If only one cache miss occurred, the search for the replacement set is started from the root of the tree. If multiple cache misses occurred simultaneously, the search starts at a tree level that has at least as many nodes as the number of cache misses. For each cache miss, a separate node is selected at that tree level, and the search for the respective replacement set starts at the selected node.