In-network coherence filtering: snoopy coherence without broadcasts

With transistor miniaturization leading to an abundance of on-chip resources and uniprocessor designs providing diminishing returns, the industry has moved beyond single-core microprocessors and embraced the many-core wave. Scalable cache coherence protocol implementations are necessary to allow fast sharing of data among various cores and drive the many-core revolution forward. Snoopy coherence protocols, if realizable, have the desirable property of having low storage overhead and not adding indirection delay to cache-to-cache accesses. There are various proposals, like Token Coherence (TokenB), Uncorq, Intel QPI, INSO and Timestamp Snooping, that tackle the ordering of requests in snoopy protocols and make them realizable on unordered networks. However, snoopy protocols still have the broadcast overhead because each coherence request goes to all cores in the system. This has substantial network bandwidth and power implications. In this work, we propose embedding small in-network co...

• Type: Conference
• Year: 2009
• Where: MICRO
• Authors: Niket Agarwal, Li-Shiuan Peh, Niraj K. Jha
• Keywords: Coherence Protocols, Hardware, In-network Coherence filters, MICRO 2009, Snoopy Protocols