Multicommodity Flow Algorithms for Buffered Global Routing

TL;DR

This paper introduces a multi-commodity flow algorithm for buffered global routing that optimizes buffer placement, wire congestion, and delay constraints, providing a practical method for tradeoff analysis.

Contribution

It presents a provably good, multi-commodity flow based algorithm capable of optimizing multiple routing parameters simultaneously, including buffer and wire sizing, with practical runtime.

Findings

Near-optimal routing results achieved

Effective tradeoff curve computation between area and congestion

Simultaneous buffer/wire sizing and layer/pin assignment

Abstract

In this paper we describe a new algorithm for buffered global routing according to a prescribed buffer site map. Specifically, we describe a provably good multi-commodity flow based algorithm that finds a global routing minimizing buffer and wire congestion subject to given constraints on routing area (wirelength and number of buffers) and sink delays. Our algorithm allows computing the tradeoff curve between routing area and wire/buffer congestion under any combination of delay and capacity constraints, and simultaneously performs buffer/wire sizing, as well as layer and pin assignment. Experimental results show that near-optimal results are obtained with a practical runtime.