GFFC: The Global Feedback Based Flow Control in the NoC Design for Many-core Processor

GFFC (Global Feedback based Flow Control) is proposed to be used in NoC design for many-core processor. GFFC is designed based on two fundamental principles: (a) when network congestion occurs, the packet sender that causes the congestion needs to know this and needs to be proactively involved in the alleviation of this network congestion; (b) the congestion-causing packets shall not block the traffic of other part of the OCN. Following these principles, we propose the GFFC FIFO in the OCN router. GFFC FIFO is a place to buffer the waiting packets in the OCN to avoid blocking the traffic of other bypassing packets. Besides, we propose a mechanism to relay the congestion in formation from the packet receiver to the packet sender via the GFFC FIFO in the routers. In this paper, we propose the design of GFFC in a mesh based OCN. We also study the performance characteristics of GFFC and report the experimental results. The experimental results show that GFFC can decrease the average non-memory packet transfer latency by 9%.