Global Routing With Timing Constraints

Abstract

We show how to incorporate global static timing constraints into global routing. Our approach is based on the min–max resource sharing model that proved successful for global routing in theory and practice. Static timing constraints are modeled by a linear number of additional resources and customers. The algorithm dynamically adjusts delay budgets and can, thus, tradeoff wiring congestion for delay. As a subroutine, the algorithm routes a single net. If this subroutine is near-optimal, we will find near-optimal solutions for the overall problem very efficiently. The approach works for many delay models; here we discuss a linear delay model (before buffering) and the Elmore delay model (after buffering). We demonstrate the benefit of our timing-constrained global routing algorithm by experimental results on industrial chips.