A Degree-Based Clustering Technique for VLSI Placement

Abstract

In this paper, clustering for the circuit placement problem is examined from the perspective of wire length contribution from groups of nets.First, the final wire length data of groups of nets with different degrees are extracted and studied. It is illustrated that nets with high-degree contribute a high percentage to the total wire length. To remedy this problem, a clustering algorithm for placement is proposed that focuses on clustering nets with high-degree. This new clustering algorithm is implemented as a preprocessing step in the placement stage. ICCAD04 benchmark circuits abstracted from IBM are used to validate the placement quality by using four academic placers with and without the proposed preprocessing step. Experiments show that the overall placement results can be improved by up to 5%.