System and method for improving directory lookup speed

A method of performing a directory lookup in a system having a main memory, a plurality of compute nodes, each having a coherence controller, a processor cache, a memory directory of the main memory and a directory cache of the memory directory, the method comprising 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.

A method of performing a cache lookup in a system comprising:

• receiving, in the directory cache, a disk or memory request;
• performing a directory lookup on the directory cache to determine a state of a disk space or memory line corresponding to the disk or memory request, respectively.