Abstract: A data processing apparatus is provided. Prefetch circuitry generates a prefetch request for a cache line prior to the cache line being explicitly requested. The cache line is predicted to be required for a store operation in the future. Issuing circuitry issues the prefetch request to a memory hierarchy and filter circuitry filters the prefetch request based on at least one other prefetch request made to the cache line, to control whether the prefetch request is issued by the issuing circuitry.

Abstract: Aspects of the present disclosure relate to an apparatus comprising processing circuitry, prefetch circuitry and prefetch metadata storage comprising a plurality of entries. Metadata items, each associated with a given stream of instructions, are stored in the prefetch metadata storage. Responsive to a given entry of the plurality of entries being associated with the given stream associated with a given metadata item, the given entry is updated. Responsive to no entry of the plurality of entries being associated with the given stream associated with a given metadata item, an entry is selected according to a default replacement policy, the given stream is allocated thereto, and the selected entry is updated based on the given metadata item. Responsive to a switch condition being met, the default selection policy is switched to an alternative selection policy comprising locking one or more entries by preventing allocation of streams to the locked entries.

Abstract: A data processing apparatus is provided. Prefetch circuitry generates a prefetch request for a cache line prior to the cache line being explicitly requested. The cache line is predicted to be required for a store operation in the future. Issuing circuitry issues the prefetch request to a memory hierarchy and filter circuitry filters the prefetch request based on at least one other prefetch request made to the cache line, to control whether the prefetch request is issued by the issuing circuitry.

Abstract: Aspects of the present disclosure relate to an apparatus comprising processing circuitry, prefetch circuitry and prefetch metadata storage comprising a plurality of entries. Metadata items, each associated with a given stream of instructions, are stored in the prefetch metadata storage. Responsive to a given entry of the plurality of entries being associated with the given stream associated with a given metadata item, the given entry is updated. Responsive to no entry of the plurality of entries being associated with the given stream associated with a given metadata item, an entry is selected according to a default replacement policy, the given stream is allocated thereto, and the selected entry is updated based on the given metadata item. Responsive to a switch condition being met, the default selection policy is switched to an alternative selection policy comprising locking one or more entries by preventing allocation of streams to the locked entries.