Technique for reducing network traffic of token protocol

Token protocol provides a flexible framework for designing new coherence protocols. It decouples performance from correctness, which allows for greater flexibility, making it possible to adapt the protocol for different systems. Unfortunately, message in token protocol are always broadcast, which creates heavy network traffic and limits its scalability. In this paper, we propose an efficient technique which employs a filter table to reduce the network traffic of token protocol in CMP systems. The filter table records the recently used blocks and provides the block's sharers and owner information. When a local cache miss happens, the core checks if a matching block exist in the filter table before broadcasting. If a matching block is found, the recorded sharer and owner information can be used to avoid a broadcast, and thus reduces network traffic. Simulation results show that our technique reduces the network traffic by 27% on average.