SYSTEM AND METHOD FOR IMPROVING DIRECTORY LOOKUP SPEED

摘要

A system and method of maintaining consistent cached copies of memory in a multiprocessor system having a main memory, includes a memory directory having entries mapping the main memory and a directory cache having records corresponding to a subset of the memory directory entries. The memory directory is preferably a full map directory having entries mapping all of the main memory or a sparse directory having entries mapping to a subset of the main memory. The method includes the steps of receiving, at the coherence controller, a signal indicative of a processor cache miss or a coherence request associated with a memory line in one of the plurality of compute nodes; determining a target coherence controller from the signal; performing a directory lookup in a directory cache of a compute node associated with the targeted coherence controller to determine a state of the memory line in each cache of the system.