A hybrid cache coherence protocol for a decoupled multi-channel optical network: SPEED DMON

This paper presents a low overhead, high performance cache coherence protocol and an interconnect architecture designed to exploit high bandwidth point-to-point and broadcast features of an optical multi-channel interconnect. SPEED DMON integrates the virtues of snoopy-based schemes and directory-based schemes into a robust hybrid architecture. Directory-assist is used exclusively for decoupled read traffic to eliminate unnecessary broadcasts while snoopy-assist is used exclusively for write and synchronization traffic to reduce directory overhead and synchronization complexities. The proposed scheme has the potential to reduce network latency by up to 85% as a result of its global independence between read and write operations, full concurrency in channel access, reduced link contention, and efficient broadcast of coherence and synchronization events