Coupling-aware high-level interconnect synthesis for low power

Ultra deep submicron (UDSM) technology and system-on-chip (SoC) have resulted in a considerable portion of power dissipated on buses, in which the major sources of the power dissipation are (1) the transition activities on the signal lines and (2) the coupling capacitances of the lines. However, there has been no easy way of optimizing (1) and (2) simultaneously at an early stage of the synthesis process. In this paper, we propose a new (onchip) bus synthesis algorithm to minimize the total sum of (1) and (2) in the microarchitecture synthesis. Specifically, unlike the previous approaches in which (1) and (2) are minimized sequentially without any interaction between them, or only one of them is minimized, we, given a scheduled dataflow graph to be synthesized, minimize (1) and (2) simultaneously by formulating and solving the two important issues in an integrated fashion: binding data transfers to buses and determining a (physical) order of signal lines in each bus, both of which are the most critical factors that affect the results of (1) and (2). Experimental results on a number of benchmark problems show that the proposed integrated low-power bus synthesis algorithm reduces power consumption by 24.8%, 40.3% and 18.1% on average over those in (J. Chang et al, Proc. of DAC, 1995) (for minimizing (1) only), (Y. Shin et al, Proc. of DAC, 2001) (for (2) only) and (both references) (for (1) and then (2)), respectively.