Simultaneous Partitioning and Signals Grouping for Time-Division Multiplexing in 2.5D FPGA-Based Systems

The 2.5D FPGA is a promising technology to accommodate a large design in one FPGA chip, but the limited number of inter-die connections in a 2.5D FPGA may cause routing failures. To resolve the failures, input/output time-division multiplexing is adopted by grouping cross-die signals to go through one routing channel with a timing penalty after netlist partitioning. However, grouping signals after partitioning might lead to a suboptimal solution. Consequently, it is desirable to consider simultaneous partitioning and signal grouping although the optimization objectives of partitioning and grouping are different, and the time complexity of such simultaneous optimization is usually high. In this paper, we propose a simultaneous partitioning and grouping algorithm that can not only integrate the two objectives smoothly, but also reduce the time complexity to linear time per partitioning iteration. Experimental results show that our proposed algorithm outperforms the state-of-the-arts flow in both cross-die signal timing criticality and system-clock periods.