Patent ID: 7076597

Claim:
A method for managing distribution of messages for changing the state of shared data in a computer system having a main memory, a memory management system, a plurality of processors, each processor having an associated cache, and employing a directory-based cache coherency comprising the method of: grouping the plurality of processors into a plurality of clusters, each cluster having a master processor and at least one slave processor; tracking copies of shared data sent to processors in the clusters; receiving an exclusive request from a processor requesting permission to modify a shared copy of the data; generating invalidate messages requesting that other processors sharing the same data invalidate that data; sending the invalidate messages to master processors in only those clusters actually containing a processor that has a shared copy of the data in the associated cache; and distributing the invalidate messages by the master processor to one or more slave processors within each cluster that contains a processor having a shared copy of the data.