PCS - Part 2: Multiprocessor Architectures

Example: SUN SF15K (3)
Within a system board: Cache coherency by snooping and
MESI
Additionally, each system board contains a SSM-agent, working
according a directory based cache coherency algorithm
Principle:
Cache coherency interactions remain local within board, as
long in a presence vector no board-distant processor is
stored.
If a copy of a memory line is stored in a board-distant
cache/processor, then SSM agent runs the distributed
protocol.
Peter Sobe
PCS - Part 2: Multiprocessor Architectures