Interconnect-power dissipation in a microprocessor

Interconnect power is dynamic power dissipation due to switching of interconnection capacitances. This paper describes the characterization of interconnect power in a state-of-the-art high-performance microprocessor designed for power efficiency. The analysis showed that interconnect power is over 50 % of the dynamic power. Over 90 % of the interconnect power is consumed by only 10 % of the interconnections. Relations of interconnect power to wire length distribution and hierarchy level of nets were examined. In light of the results, a router’s algorithms were modified, to use larger wire spacing and minimal length routing for the high power consuming interconnects. The power-aware router algorithm was tested on synthesized blocks, demonstrating average saving of 14 % in the dynamic power consumption without timing degradation or area increase. The results demonstrate the obtainable benefits of tuning physical design algorithms to save power.