Set-associative cache using cache line decay counts and set overflow

Abstract

Embodiments of a method for reducing conflict misses in a set-associative cache by mapping each memory address to a primary set and at least one overflow set are described. If a conflict miss occurs within the primary set, a cache line from the primary set is selected for replacement. However, rather than removing the selected cache line from the cache completely, the selected cache line may instead be relocated to the overflow set. The selected cache line replaces a cache line in the overflow set, if it is determined that the selected cache line from the primary set has an estimated age that is more recent than an estimated age for any cache line in the overflow set. Embodiments of the method incorporate various techniques for estimating the age of cache lines, and, particularly, for estimating the relative time since any given cache line was last accessed.