Performance evaluation of hybrid hardware and software distributed shared memory protocols
Rohit Chandra, Kourosh Gharachorloo, Vijayaraghavan Soundararajan, Anoop Gupta · 1994
Hardware distributed shared memory (DSM) systems efficiently support fine grain sharing of data by maintaining coherence at the level of individual cache lines and providing automatic replication in processor caches. Software DSM systems, on the other hand, amortize high communication costs by maintaining coherence at coarser granularities and replicating data at the level of local main memories. Even though software DSM systems have traditionally been targeted towards loosely coupled environments, some of the techniques are potentially useful in the context of tightly coupled multiprocessors. In particular, communicating data at a coarse grain can sometimes be more efficient than transferring the data as individual cache lines. Furthermore, replication in local memories can accommodate applications with larger working sets as compared to replication in processor caches only. Therefore, combining the two techniques in a hybrid protocol can potentially exploit the benefits of each approach.