Interconnect-power dissipation in a microprocessor

ABSTRACT

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.

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INDEX TERMS

Primary Classification:
  B. Hardware
  B.7 INTEGRATED CIRCUITS
      B.7.1 Types and Design Styles
          Subjects: Microprocessors and microcomputers

Additional Classification:
  B. Hardware
  B.7 INTEGRATED CIRCUITS
      B.7.2 Design Aids
          Subjects: Placement and routing

General Terms:
Design, Performance

Keywords:
interconnect power, low-power design, routing, wire spacing