Journal of KIISE:Computing Practices and Letters (한국정보과학회논문지:컴퓨팅의 실제 및 레터)

Korean Institute of Information Scientists and Engineers (한국정보과학회)
권호 표지

Improved Global Placement Technique to Relieve Routing Congestion

배선 밀집도를 완화하기 위한 개선된 광역배치 기법

  • 오은경 (동아대학교 컴퓨터공학과) ;
  • 허성우 (동아대학교 컴퓨터공학과)
  • Published : 2008.06.15
Download PDF
⟨ Previous Next ⟩

Abstract

Since previous work CDP(Congestion Driven Placement) [1] considers all possible directions to move every cell in nets which contribute highly to routing congestion, it consumes CPU time a lot. In this paper, we propose a faster global placement technique, so called ICDGP(Improved Congestion Driven Global Placement) to relieve the routing congestion. ICDGP uses the force-directed method to determine the target locations of the cells in the nets in the congested spots, and considers only to move the target location for each cell. If moving multiple cells simultaneously is considered better than moving each cell one by one it moves multiple cells simultaneously. By experimental results, ICDGP produces less congested placement than CDP does. Particularly, the CPU time is reduced by 36% on average.

기존의 CDP(Congestion Driven Placement) 기법[1]은 배선 밀집도에 크게 기여하는 넷에 속한 모든 셀들을 옮길 때 가능한 방향을 모두 고려하기 때문에 CPU 시간을 많이 소모한다. 본 논문에선 배선 밀집도를 완화하기 위한 빠른 배치 기법, 즉 ICDGP(Improved Congestion Driven Global Placement)라 불리는 개선된 기법을 제안한다. ICDGP는 밀집된 지역에 있는 넷에 속한 셀들의 이동 목표 지점을 정하기 위해 force-directed 기법을 사용하며, 각 셀은 이동 목표 지점으로만 옮기는 것을 고려한다. ICDGP는 또한 셀을 하나씩 옮기는 것보다 다수의 셀을 동시에 같이 옳기는 것이 낫다고 판단되면 같이 옮긴다. 실험 결과에 의하면 CDP보다 ICDGP가 배선 밀집도 면에서 좋은 배치를 생성한다. 특히 CPU 시간은 평균 36% 개선되었다.

Keywords

References

  1. 오은경, 허성우, "배선밀집도 드리븐 배치", 한국정보처리학회 논문지, 제13-A권, 제1호, pp. 57-70, 2006 https://doi.org/10.3745/KIPSTA.2006.13A.1.057
  2. A. E. Caldwell, A. B. Kahng, and I.L. Markov, "Can Recursive Bisection Alone Produce Routable Placements?," Proc. of DAC, pp. 477-482, 2000
  3. M.C.Yildiz and P.H.Madden "Improved Cut Sequences for Partitioning Based Placement," Proc. of DAC, pp. 776-729, 2001
  4. A. Agnihotri, et al. "Fractional Cut: Improved Recursive Bisection Placement," Proc. of ICCAD, pp. 307-310, 2003
  5. X. Yang, M. Wang, K. Egur and M. Sarrafzadeh, "A Snap-on Placement Tool," Proc. of ISPD, pp. 153-158, 2000
  6. A.B.Kahng and S. Reda, "Wirelength Minimization for Min-Cut Placements via Placement Feedback," IEEE Trans. on CAD of Integrated Circuits and Systems, Vol.25, No.7, pp. 1301-1312, 2006 https://doi.org/10.1109/TCAD.2005.855917
  7. Wern-Jieh and Carl Sechen, "Efficient and Effective Placement for Very Large Circuits," IEEE Trans. on CAD of Integrated Circuits and Systems, pp. 349-359, 1995
  8. G. Meixner and U. Lauther, "Congestion-Driven Placement Using a New Multi-Partitioning Heuristic," Porc. of ICCAD, pp. 332-335, 1990
  9. X. Yang, B-K. Choi, and M. Sarrafzadeh, "Routability Driven White Space Allocation for Fixed- die Standard Cell Placement," Proc. of ISPD, pp. 42-50, 2002
  10. S. Hur and J. Lillis, "Mongrel: Hybrid Techniques for Standard Cell Placement," Proc. of ICCAD, pp. 165-170, 2000
  11. H. Eisenmann and F. M. Johannes, "Generic Global Placement and Floorplanning," Proc. of DAC, pp. 269-274, 1998