Patent ID: 7437520
Filing Date: 2008-10-14
Classification: G06F

Abstract:
1. A method of adaptive snoop-and-forward, the method comprising the steps of: receiving a cache request from a preceding node with a preceding PCSR (“partially combined snoop response”) from a preceding node; if the preceding PCSR indicates that requested data of the cache request has already been supplied, forwarding the cache request to a subsequent node; if the preceding PCSR indicates that the requested data of the cache request has not been supplied, conducting a snoop-and-forward prediction to determine whether one of lazy forwarding or eager forwarding should be used in handling the cache request; if lazy forwarding if predicted, (a) performing an intra-node cache snoop operation to generate an intra-node cache snoop response, the intra-node cache snoop response indicating whether requested data of the cache request can be supplied, and (b) forwarding the cache request to a subsequent node after the intra-node cache snoop response becomes available; and if eager forwarding is predicted, (a) forwarding the cache request to a subsequent node, and (b) performing an intra-node cache snoop operation to generate an intra-node cache snoop response, the intra-node cache snoop response indicating whether requested data of the cache request can be supplied.