Link-Sharing: Regional Congestion Aware Routing in 2D NoC by Propagating Congestion Information on Idle Links

摘要

Congestion aware routing plays an important role in balancing the Networks-on-Chip (NoC) traffic load to diminish the communication cost. Theoretically, the more detailed network congestion information is collected, the better routing decision can be made. However, the congestion information propagation methods employed by state of the art designs usually have drawbacks like long update interval, nonnegligible link wiring overhead, or can only propagate abbreviated congestion information. Noticing that NoC link utilization rate is typically low, we propose a Link-Sharing method which propagates congestion information on the normal data links during their idle cycles. Be benefited from the wide link bandwidth, Link-Sharing enables each router to have a more detailed and timely updated network status overview than counterpart congestion aware routing algorithms, and thus can make more sophisticated routing decision to avoid the congested area. When compared with the counterpart methods, Link-Sharing is able to improve the NoC saturation point by up to 20.8 % with negligible area and power overhead.