Application-Specific Protocols for User-Level Shared Memory

Abstract:

Recent distributed shared memory (DSM) systems and proposed
shared-memory machines have implemented some or all of their cache
coherence protocols in software. One way to exploit the flexibility
of this software is to tailor a coherence protocol to match an
application's communication patterns and memory semantics. This paper
presents evidence that this approach can lead to large performance
improvements. It shows that application-specific protocols
substantially improved the performance of three application
programs--appbt, em3d, and barnes--over carefully tuned transparent
shared memory implementations. The speed-ups were obtained on
Blizzard, a fine-grained DSM system running on a 32-node Thinking
Machines CM-5.