Design of energy-efficient channel buffers with router bypassing for network-on-chips (NoCs)

Network-on-chip (NoC) architectures are fast becoming an attractive solution to address the interconnect delay problems in chip multiprocessors (CMPs). However, increased power dissipation and limited performance improvements have hindered the wide-deployment of NoCs. In this paper, we combine two techniques of adaptive channel buffers and router pipeline bypassing to simultaneously reduce power consumption and improve performance. Power consumption can be decreased by reducing the size of the router buffers. However, as reducing router buffers alone will significantly degrade performance, we compensate by utilizing the newly proposed dual-function channel buffers that allow flits to be stored on wires when required. Network bypassing technique, on the other hand, allows flits to bypass the router pipeline and thereby avoid the router buffers altogether. We combine the two techniques and attempt to keep the flits on the wires from source to destination. Our simulation results of the proposed methodology combining the two techniques, yield a overall power reduction of 62% over the baseline and improve performance (throughput and latency) by more than 10%.