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 that are cached in remote clusters. Techniques
are provided for managing eviction of entries in the cache coherence directory
by locking memory lines in a home cluster without causing a memory controller to
generate probes to processors in the home cluster.