In deep submicron (DSM) era, the communication between different components is increasing significantly. It is not uncommon to see floorplanning problems with a relatively small number of blocks (e.g., 50) but has a large number of nets (e.g. 20K). Since existing floorplanning algorithms use simulated annelaing which needs to examine a large number of floorplans, the increasing number of nets has made interconnect-centric floorplanning computaionally very expensive. Moreover, there is almost no systematic way to resolve the congestion problem in such magnitude of number of nets in a given floorplan. In this paper, we present a simple yet effective idea to significantly reduce the runtime of interconnect-centric florplanning algorithms. Our idea is to group common nets between two blocks into a single net. This faster wiring evaluation technique is very effective. We also present a more accurate global router for wiring evaluation based on Lagrangian Relaxation. The new router helps further congestion reduction while doing interconnect planning in floorplanning. We have incorporated our algorithms into  and observed dramatic improvement in runtime. For a 33-block 15K-net problem, we reduced runtime from over 23 hours to less than 50 minutes.
|Number of pages||6|
|Journal||Proceedings of the IEEE Great Lakes Symposium on VLSI|
|State||Published - 1 Jan 2001|
|Event||11th Great Lakes Sysmposium on VLSI (GLSVLSI 2001) - West Lafayette, IN, United States|
Duration: 22 Mar 2001 → 23 Mar 2001