US Patent 7853754 Caching in multicore and multiprocessor architectures

A multicore processor comprises a plurality of cache memories; a plurality of processor cores, each associated with one of the cache memories; one or more memory interfaces providing memory access paths from the cache memories to a main memory; and one or more directory controllers for respective portions of the main memory, each associated with corresponding storage for directory state. Each corresponding storage provides space for maintaining directory state for each memory line that is indicated as stored in at least one of the cache memories such that the space for maintaining directory state is independent of the size of the main memory.