Cache coherence directory eviction mechanisms are described for use in computer
systems having a plurality of multiprocessor clusters. Interaction among the clusters
is facilitated by a cache coherence controller in each cluster. A cache coherence
directory is associated with each cache coherence controller identifying memory
lines associated with the local cluster which are cached in remote clusters. The
cache coherence controller is operable to initiate eviction of an entry in its
directory corresponding to an unmodified copy of a memory line by sending a request
to write to the memory line to a corresponding memory controller.
