Evaluation of placer suboptimality via zero-change netlist transformations

In this paper we introduce the concept of zero-change transformations to quantify the suboptimality of existing placers. Given a netlist and its placement from a placer, we formally define a class of netlist transformations that produce different netlists from the given netlist but have the same Half-Perimeter Wire Length (HPWL). Furthermore, the optimal HPWL value of the new netlists is no less than that of the original netlist. By applying our transformations and re-executing the placer, we can interpret any deviation in HPWL as a lower bound to the deviation from the optimal HPWL value. Such deviation is a measure of suboptimality. Using these transformations, the suboptimality of several existing academic and industrial placers is studied on the IBM benchmarks. Our results show that current placers are suboptimal for zero-change transformations with deviations in HPWL by up to 32% on the IBM (version 1) benchmarks. The specific nature of our transformations also pinpoints possi...

• Type: Conference
• Year: 2005
• Where: ISPD
• Authors: Andrew B. Kahng, Sherief Reda
• Keywords: Hardware, ISPD 2005, Netlists, Optimal Hpwl Value, Zero-change Transformations