physical hierarchy generation with routing congestion control
In this paper, we develop a multi-level physical hierarchy generation (mPG) algorithm integrated with fast incremental global routing for directly updating and optimizing congestion cost during placement. The fast global routing is achieved by using a fast two-bend routing and incremental A-tree algorithm. The routing congestion is modeled by the wire usage estimated by the fast global router. A hierarchical area density control is also developed for placing objects with significant size variations. Experimental results show that, compared to Gordian-L , the wire length driven mPG is 3-6.5 times faster and generates slightly better wire length for test circuits larger than 100K cells. Moreover, the congestion driven mPG improves 50\% wiring overflow with 5\% larger bounding box wire length but 3-6\% shorter routing wire length measured by graph based A-tree.
physical hierarchy hierarchic generation routing congestion control congestion control paper algorithm integrability incremental global routing global update optimality cost place placement router object size variation experimentation test circuits graph tree interconnect deep sub-micron