Quadratic placement using an improved timing model

The performance of timing-driven placement methods depends strongly on the choice of the net model. In this paper a more precise net model is presented that does not increase numerical complexity. We introduce a method that replaces the clique model of a net by a tree model in the quadratic placement formulation. This improvement enables us to control the length of every tree segment separately. Furthermore, we present an analysis of the effects of every tree segment to the net delay. The result is in turn used to control the placement engine. Our presented results are based on legal placements. They show significant improvements over state-of-the art methods. Categories and Subject Descriptors J.6 [Computer-Aided Engineering]: Computer-aided design (CAD)--Physical Design, Layout Synthesis, Placement General Terms Algorithms, Design Keywords timing driven placement, Quadratic placement, Steiner tree net model, sensitivity, optimization potential

• Type: Conference
• Year: 2004
• Where: DAC
• Authors: Bernd Obermeier, Frank M. Johannes
• Keywords: Computer Architecture, DAC 2004, Net Model, Quadratic Placement, Tree Segment