Methods and apparatus for training prefetch information

An apparatus comprising:

• prefetch information storage circuitry to store prefetch information associated with respective data address regions, the prefetch information in respect of a given data address region identifying expected access patterns associated with the given data address region;
• prefetch training circuitry, comprising a plurality of entries, to:
• allocate a given entry to a given data address region;
• receive access information indicative of data accesses within the given data address region;
• based on said access information, train prefetch information associated with the given data address region, the prefetch information being indicative of a pattern of said data accesses within the given data address region;
• and
• responsive to an eviction condition being met after an elapsed period, since said allocation of the given entry, has exceeded a threshold, perform an eviction comprising transferring the prefetch information associated with the given data address region to the prefetch information storage circuitry.