Quality & Generality: A Flexible FPGA Re-Clustering Technique to Improve Packing and Placement

Abstract

The Packing and Placement stages are two major steps in the FPGA backend flow which greatly affect the Quality-of-Results (QoR) of design implementation. While these problems have been extensively studied in the literature, most approaches have either sacrificed generality by targeting specific and simplified FPGAs with few “block packing” legality constraints, or sacrificed quality by making irreversible packing decisions early in the flow and hence constraining the optimizations available to the subsequent placement stage. In this paper, we propose a new (re-clustering API) that can be used to update the packed netlist at different points throughout the packing and placement stages. This API can be used in our proposed flow to improve the QoR while preserving the generality and flexibility of the flow and ensuring the legality of the solution for any proposed FPGA architecture.