Finding System-Level Information and Analyzing Its Correlation to FPGA Placement

One of the more popular placement algorithms for Field Programmable Gate Arrays (FPGAs) is called Simulated Annealing (SA). This algorithm tries to create a good quality placement from a flattened design that no longer contains any high-level information related to the original design hierarchy. Unfortunately, placement is an NP-hard problem and as the size and complexity of designs implemented on FPGAs increases, SA does not scale well to find good solutions in a timely fashion. As modern FPGAs can be used to implement Systems- and Networks-on-Chip, designers are required to spend an increasing amount of time waiting for place and route tools to complete that is not being matched by an increase in the power of computing work stations. In this paper, we investigate if system-level information can be reconstructed from a flattened netlist and evaluate how that information is realized in terms of its locality in the final placement. If there is a strong relationship between good quality placements and system-level information, then it may be possible to divide a large design into smaller components and improve the time needed to create a good quality placement. Our preliminary results suggest that the locality property of the information embedded in the system-level HDL structure (i.e. “module”, “always”, and “if” statements) is greatly affected by both the designer and the design itself. A reconstructive algorithm, called affinity propagation, is also considered as a possible method of generating a meaningful coarse grain picture of the design.