Parallel simulated annealing strategies for VLSI cell placement

Simulated annealing based standard cell placement for VLSI designs has long been acknowledged as a compute-intensive process, and as a result several research efforts have been undertaken to parallelize this algorithm. Most previous parallel approaches to cell placement annealing have used a parallel moves approach. In this paper we investigate two new approaches that have been proposed for generalized parallel simulated annealing but have not been applied to the cell placement problem. Results are presented on the effectiveness of implementations of these algorithms when applied to the cell placement problem. We find that the first, multiple Markov chains, appears to be promising since it uses parallelism to obtain near linear speedups with no loss in quality. The second, speculative computation, while maintaining quality is not suitable since no speedups are achieved due to the specific nature of the cell placement problem. The two algorithms are compared with the parallel moves approach to parallel cell placement.