Patent ID: 7480770
Filing Date: 2009-01-20
Classification: G06F

Abstract:
1. A node for a multi-node computer system, the node comprising: a coherence directory comprising a plurality of entries, wherein each entry corresponds to a respective coherence unit and stores a state identifying which nodes in the computer system are storing a copy of the coherence unit and further identifying a coherence state of the coherence unit according to a coherence protocol implemented in the computer system; and a coherence controller coupled to the directory and coupled to receive a first request for a requested coherence unit having a first entry in the coherence directory, and wherein the coherence controller is coupled to receive a second request for the requested coherence unit, and wherein the coherence controller is configured to selectively initiate coherence activity for the second request, prior to a completion of coherence activity for the first request, dependent on a type of the second request, wherein the first request is transmitted by a first requesting node, and wherein the first request identifies the requested coherence unit and requests that a specified coherency state for the requested coherence unit be provided to the first requesting node, and wherein the second request is transmitted by a second requesting node different from the first requesting node, and wherein the second request identifies the requested coherence unit and requests that a specified coherency state for the requested coherence unit be provided to the second requesting node.