Prefetch circuitry with compression for demoted entries

Abstract

Disclosed techniques related to compressed storage for access maps demoted from a prefetch table. In some embodiments, prefetch circuitry stores access map data based on address information corresponding to memory accesses, where a given access map of a plurality of stored access maps records categories of prior accesses to different offsets in a defined address region. The prefetch circuit may generate, based on the access map data and stored access patterns, one or more prefetch requests to prefetch data to a cache. Compressed map storage circuitry may store first data from a first access map, where the first data is a proper subset of data stored in the first access map prior to demotion of the first access map from the prefetch table. At least a portion of the first data may be a compressed version of data from the first access map.