Improved Parallel Legalization Schemes for Standard Cell Placement with Obstacles†
AbstractIn standard cell placement, a circuit is given consisting of cells with a standard height, (different widths) and the problem is to place the cells in the standard rows of a chip area so that no overlaps occur and some target function is optimized. The process is usually split into at least two phases. In a first pass, a global placement algorithm distributes the cells across the circuit area, while in the second step, a legalization algorithm aligns the cells to the standard rows of the power grid and alleviates any overlaps. While a few legalization schemes have been proposed in the past for the basic problem formulation, few obstacle-aware extensions exist. Furthermore, they usually provide extreme trade-offs between time performance and optimization efficiency. In this paper, we focus on the legalization step, in the presence of pre-allocated modules acting as obstacles. We extend two known algorithmic approaches, namely Tetris and Abacus, so that they become obstacle-aware. Furthermore, we propose a parallelization scheme to tackle the computational complexity. The experiments illustrate that the proposed parallelization method achieves a good scalability, while it also efficiently prunes the search space resulting in a superlinear speedup. Furthermore, this time performance comes at only a small cost (sometimes even improvement) concerning the typical optimization metrics. View Full-Text
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Oikonomou, P.; Dadaliaris, A.N.; Kolomvatsos, K.; Loukopoulos, T.; Kakarountas, A.; Stamoulis, G.I. Improved Parallel Legalization Schemes for Standard Cell Placement with Obstacles. Technologies 2019, 7, 3.
Oikonomou P, Dadaliaris AN, Kolomvatsos K, Loukopoulos T, Kakarountas A, Stamoulis GI. Improved Parallel Legalization Schemes for Standard Cell Placement with Obstacles. Technologies. 2019; 7(1):3.Chicago/Turabian Style
Oikonomou, Panagiotis; Dadaliaris, Antonios N.; Kolomvatsos, Kostas; Loukopoulos, Thanasis; Kakarountas, Athanasios; Stamoulis, Georgios I. 2019. "Improved Parallel Legalization Schemes for Standard Cell Placement with Obstacles." Technologies 7, no. 1: 3.
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