Abstract: An apparatus comprises a cache to store information, items of information in the cache being associated with addresses; cache lookup circuitry to perform lookups in the cache; and a prefetcher to prefetch items of information into the cache in advance of an access request being received for said items of information. The prefetcher selects addresses to train the prefetcher. In response to determining that a cache lookup specifying a given address has resulted in a hit and determining that a cache lookup previously performed in response to a prefetch request issued by the prefetcher for the given address resulted in a hit, the prefetcher selects the given address as an address to be used to train the prefetcher.

Abstract: An apparatus comprises prefetch circuitry, and a cache having a plurality of entries to store data for access by processing circuitry and blocks of metadata for reference by the prefetch circuitry. The prefetch circuitry can detect one or more access sequences in dependence on training inputs derived from demand accesses processed by the cache in response to memory access operations performed by the processing circuitry. On detecting a given access sequence, this causes an associated given block of metadata providing information indicative of the given access sequence to be stored in a selected entry of the cache. Eviction control circuitry, responsive to a victimisation event, performs an operation to select a victim entry in the cache, the victim entry being selected from one or more candidate victim entries.

Abstract: An apparatus comprises prefetch circuitry, and a cache having a plurality of entries to store data for access by processing circuitry and blocks of metadata for reference by the prefetch circuitry. The prefetch circuitry can detect one or more access sequences in dependence on training inputs derived from demand accesses processed by the cache in response to memory access operations performed by the processing circuitry. On detecting a given access sequence, this causes an associated given block of metadata providing information indicative of the given access sequence to be stored in a selected entry of the cache. Eviction control circuitry, responsive to a victimisation event, performs an operation to select a victim entry in the cache, the victim entry being selected from one or more candidate victim entries.

Abstract: Prefetch circuitry generates prefetch requests to prefetch information to a cache, based on prediction information trained using a training table comprising training entries. A given training entry associates a program counter indication associated with a trigger training memory access, a region indication indicative of a memory address region comprising a target address specified by the trigger training memory access, corresponding prediction information trained based on subsequent training memory access requests specifying target addresses in the same region as the target address of the trigger training memory access, and first and second replacement policy information. The first replacement policy information is used for replacement of an entry with another entry for the same program counter indication but different region. The second replacement policy information is used for replacement of an entry with another entry for a different program counter indication.

Abstract: An apparatus comprises a cache to store information, items of information in the cache being associated with addresses; cache lookup circuitry to perform lookups in the cache; and a prefetcher to prefetch items of information into the cache in advance of an access request being received for said items of information. The prefetcher selects addresses to train the prefetcher. In response to determining that a cache lookup specifying a given address has resulted in a hit and determining that a cache lookup previously performed in response to a prefetch request issued by the prefetcher for the given address resulted in a hit, the prefetcher selects the given address as an address to be used to train the prefetcher.