Communication and Replication
Comm induced by finite capacity is most fundamental artifact
- Like cache size and miss rate or memory traffic in uniprocessors
- Extended memory hierarchy view useful for this relationship
View as three level hierarchy for simplicity
- Local cache, local memory, remote memory (ignore network topology)
Classify “misses” in “cache” at any level as for uniprocessors
- compulsory or cold misses (no size effect)
- capacity misses (yes)
- conflict or collision misses (yes)
- communication or coherence misses (no)
- Each may be helped/hurt by large transfer granularity (spatial locality)