Copyright © 2007 The Institute of Electronics, Information and Communication Engineers
Regular Section -- Papers -- VLSI Design Technology and CAD |
Stochastic Interconnect Tree Construction Algorithm with Accurate Delay and Power Consideration*
1 The authors are with the Department of Computer Science and Technology, Tsinghua University, Beijing, China. E-mail: wangyibo{at}mails.tsinghua.edu.cn, E-mail: caiyc{at}tsinghua.edu.cn, E-mail: hxl-dcs{at}tsinghua.edu.cn, E-mail: zou_yi00{at}mails.tsinghua.edu.cn
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Abstract |
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Buffer insertion plays a great role in modern global interconnect optimization. But too many buffers exhaust routing resources, and result in the rise of the power dissipation. Unfortunately, simplified delay models used by most of the present buffer insertion algorithms may introduce redundant buffers due to the delay estimation errors, whereas accurate delay models expand the solution space significantly, resulting in unacceptable runtime. Moreover, the power dissipation problem becomes a dominant factor in the state-of-the-art IC design. Not only transistor but also interconnect should be taken into consideration in the power calculation, which makes us have to use an accurate power model to calculate the total power dissipation. In this paper, we present two stochastic optimization methods, simulated annealing and solution space smoothing, which use accurate delay and power models to construct buffered routing trees with considerations of buffer/wire sizing, routing obstacles and delay and power optimization. Experimental results show our methods can save much of the buffer area and the power dissipation with better solutions, and for the cases with pins 
15, the runtime of solution space smoothing is tens of times faster.
Key Words: interconnect optimization, accurate delay model, low power, buffer insertion
Manuscript received May 15, 2006. Manuscript revised December 2, 2006. Final manuscript received February 2, 2007.
* This paper is supported by the National Science Foundation of China (NSFC) 60476014.