Virtual Tree Coherence: Leveraging Regions and In-Network Multicast Trees for Scalable Cache Coherence
Scalable cache coherence solutions are imperative to drive the many-core revolution forward. To fully realize the massive computation power of these many-core architectures, the communication substrate must be carefully examined and streamlined. There is tension between the need for an ordered interconnect to simplify coherence and the need for an unordered interconnect to provide scalable communication. In this work, the authors propose a coherence protocol, Virtual Tree Coherence (VTC), that relies on a virtually ordered interconnect. The virtual ordering can be overlaid on any unordered interconnect to provide scalable, high-bandwidth communication.