In-Network Cache Coherence

With the trend towards increasing number of processor cores in future chip architectures, scalable directory-based protocols for maintaining cache coherence will be needed. However, directory-based protocols face well-known problems in delay and scalability. Most current protocol optimizations targeting these problems maintain a firm abstraction of the interconnection network fabric as a communication medium: protocol optimizations consist of endto-end messages between requestor, directory and sharer nodes, while network optimizations separately target lowering communication latency for coherence messages. In this paper, we propose an implementation of the cache coherence protocol within the network, embedding directories within each router node that manage and steer requests towards nearby data copies, enabling in-transit optimization of memory access delay. Simulation results across a range of SPLASH-2 benchmarks demonstrate significant performance improvement and good system scal...

• Type: Conference
• Year: 2006
• Where: MICRO
• Authors: Noel Eisley, Li-Shiuan Peh, Li Shang
• Keywords: Cache Coherence, Cache Coherence Protocol, Directory-based Protocols, Hardware, MICRO 2006