Patent ID: 6901482

Claim:
A method for managing ownership of a cache line in a system including a plurality of processing clusters directly coupled to a snoop controller via respective point-to-point links, wherein said processing clusters and said snoop controller are further coupled via a snoop ring, and wherein a first processing cluster in said plurality of processing clusters includes a first tier cache memory and a second tier cache memory coupled to said first tier cache memory, said method comprising the steps of: (a) issuing a store-create command for a memory location to said first tier cache memory; (b) forwarding a memory request including said store-create command to said second tier cache memory; (c) determining whether said second tier cache memory has sole ownership of said memory location; and (d) ownership of said memory location being relinquished by at least one processing cluster in said set of processing clusters, if it is determined in said step (c) that said second tier cache memory does not have sole ownership of said memory location, wherein said step (d) includes the steps of: (1) forwarding said memory request including said store-create command to said snoop controller via the respective point-to-point link coupling the first processing cluster to the snoop controller; and (2) issuing instructions from said snoop controller to said processing clusters via said snoop ring to direct said plurality of processing clusters to relinquish ownership of said memory location.