The maximum concurrent flow problem
Journal of the ACM (JACM)
RISA: accurate and efficient placement routability modeling
ICCAD '94 Proceedings of the 1994 IEEE/ACM international conference on Computer-aided design
On the behavior of congestion minimization during placement
ISPD '99 Proceedings of the 1999 international symposium on Physical design
Routability-driven repeater block planning for interconnect-centric floorplanning
ISPD '00 Proceedings of the 2000 international symposium on Physical design
Integrated floorplanning and interconnect planning
ICCAD '99 Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design
Estimating routing congestion using probabilistic analysis
Proceedings of the 2001 international symposium on Physical design
A new congestion-driven placement algorithm based on cell inflation
Proceedings of the 2001 Asia and South Pacific Design Automation Conference
Twin binary sequences: a non-redundant representation for general non-slicing floorplan
Proceedings of the 2002 international symposium on Physical design
Algorithms for VLSI Physcial Design Automation
Algorithms for VLSI Physcial Design Automation
Introduction to Algorithms
Congestion reduction during placement based on integer programming
Proceedings of the 2001 IEEE/ACM international conference on Computer-aided design
Fast Hierarchical Floorplanning with Congestion and Timing Control
ICCD '00 Proceedings of the 2000 IEEE International Conference on Computer Design: VLSI in Computers & Processors
Congestion Estimation with Buffer Planning in Floorplan Design
Proceedings of the conference on Design, automation and test in Europe
DATE '03 Proceedings of the conference on Design, Automation and Test in Europe - Volume 1
An effective congestion-driven placement framework
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
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Congestion has been a topic of great importance in the floorplanning of deep-submicron 0 design. In this paper, we design an accurate and efficient congestion estimation model by performing global routing. We interpret the global routing problem as a flow problem of several commodities and relax the integral flow constraints. The objective of resulting fractional flow problem is to minimize the maximum congestion over all edges in the inner dual graph [13]. The underlying routing graph for each commodity is derived by assigning directions to the inner dual graph edges. We design an efficient two-phase algorithm to solve this fractional flow problem. The first phase is denoted as Incoming Flow Balancing (IFB) by which a good initial solution is derived. The second phase is called Stepwise Flow Refinement (SFR) by which the maximum congestion of the solution in first phase is iteratively reduced to its optimal value. In addition, a valid global routing solution can be obtained by applying a simple rounding procedure on the fractional flow solution. The maximum congestion after rounding is only increased by 2.82% on average according to our experimental results, which justifies the use of fractional flow to estimate the routing congestion. Finally, we demonstrate our model by integrating it into a simulated annealing (SA) based floorplanner, where we use the maximum congestion as part of the cost of SA. The experimental results show that, on average, our congestion-driven floorplanner can generate a much less congested floorplan (-36.44%) with a slight sacrifice in area (+1.30%) and wirelength (+2.64%). The runtime of the whole SA process is only increased moderately (+270%).