Patent ID: 7543115

Claim:
A system having a messaging protocol for a plurality of caching agents and a plurality of home agents each guards a piece of coherent memory coupled via a network fabric, the system comprising: an interface circuit supports the plurality of caching agents supports modified, exclusive, shared, invalid and forward (MESIF) cache states and a home agent determining a winner of a conflict corresponding to a conflict message received by the home agent for an address among at least two of the plurality of caching agents and the home agent requests the data from a requester to be sent to the winner of the conflict responsive to a release forward message from the home agent to the requester and causes the requester to send a latest copy of the data to the winner of the conflict and to downgrade and maintain the latest copy of the data until a final release message is received, and causes a victim message to be sent to the home agent and a block victim message to be sent to the winner, the release forward message is selected from a plurality of release messages based on a request type; and the interface circuit to allow at least one of the plurality of home agents to sink all request, acknowledgement, and response messages without a dependency on a forward progress of any other message.