Cache storage for multiple requesters and usage estimation thereof

A cache memory and method of operating a cache memory are provided. The cache memory comprises cache storage that stores cache lines for a plurality of requesters and cache control circuitry that controls insertion of a cache line into the cache storage when a memory access request from one of the plurality of requesters misses in the cache memory. The cache memory further has cache occupancy estimation circuitry that holds a count of insertions of cache lines into the cache storage for each of the plurality of requesters over a defined period. The count of cache line insertions for each requester thus provides an estimation of the cache occupancy associated with each requester.