Performance Evaluation of Congestion-Aware Routing with DVFS on a Millimeter-Wave Small-World Wireless NoC

Abstract

The mm-wave small-world wireless NoC (mSWNoC) has emerged as an enabling interconnection infrastructure for designing high-bandwidth and energy-efficient multicore chips. In this mSWNoC architecture, long-range communication predominately takes place through the wireless shortcuts operating in the range of 10--100GHz, whereas short-range data exchange occurs through conventional metal wires. This results in performance advantages (lower latency and energy dissipation), mainly stemming from using the wireless links as long-range shortcuts between far-apart cores. The performance gain introduced by the wireless channels can be enhanced further if the wireline links of the mSWNoC are optimized according to the traffic patterns arising out of the application workloads. While there is significant energy savings, and hence temperature reduction, in the network due to the mSWNoC architecture, a load-imbalanced network is still susceptible to local temperature hotspots. In this work, we demonstrate that by incorporating congestion-avoidance routing with network-level dynamic voltage and frequency scaling (DVFS) in an mSWNoC, the power and thermal profiles can be improved without a significant impact on the overall network performance. In this work, we demonstrate how novel interconnect architectures enabled by the on-chip wireless links coupled with power management strategies can improve the energy and thermal characteristics of an mSWNoC significantly without introducing any performance degradation with respect to the conventional mesh-based NoC.