Improving Timing-Driven FPGA Packing with Physical Information

The traditional approach to FPGA packing and CLB-level placement has been shown to yield significantly worse quality than approaches which allow BLEs to move during placement. In practice, however, modern FPGA architectures require expensive DRC checks which can render full BLE-level placement impractical. We address this problem by proposing a novel clustering framework that uses physical information to produce better initial packings which can, in turn, reduce the amount of BLE-level placement that is required. We quantify our packing technique across accepted benchmarks and show that it produces results with 16% less wire length, 19% smaller minimum channel widths, and 8% less critical path delay, on average, than leading methods.