Interconnect-aware High-level Synthesis for Low Power

Interconnects (wires, buffers, clock distribution networks, multiplexers and busses) consume a significant fraction of total circuit power. In this work, we demonstrate the importance of optimizing on-chip interconnects for power during high-level synthesis. We present a methodology to integrate interconnect power optimization into high-level synthesis. Our binding algorithm not only reduces power consumption in functional units and registers in the resultant register-transfer level (RTL) architecture, but also optimizes interconnects for power. We take physical design information into account for this purpose. To estimate interconnect power consumption accurately for deep sub-micron (DSM) technologies, wire coupling capacitance is taken into consideration. We observed that there is significant spurious (i.e., unnecessary) switching activity in the interconnects and propose techniques to reduce it. Compared to interconnect-unaware power-optimized circuits, our experimental results show that interconnect power can be reduced by 53.1% on an average, while reducing overall power by an average of 26.8% with 0.5% area overhead. Compared to area-optimized circuits, the interconnect power reduction is 72.9% and overall power reduction is 56.0% with 44.4% area overhead