Mixed integer linear programming-based optimal topology synthesis of cascaded crossbar switches

We present a topology synthesis method for high performance System-on-Chip (SoC) design. Our method provides an optimal topology of on-chip communication network for the given bandwidth, latency, frequency and/or area constraints. The optimal topology consists of multiple crossbar switches and some of them can be connected in a cascaded fashion for higher clock frequency and/or area efficiency. Compared to previous works, the major contribution of our work is the exactness of the solution from two aspects. First, the solving method of our work is exact by employing the mixed integer linear programming (MILP) method. Second, we generalize the crossbar switch representation in MILP in order that the optimal topology can include any arbitrary sizes of crossbar switches together. The experimental results show that the topologies optimized for the clock frequency (area) give up to 37.3% (12.7%) improvements compared to the conventional single large crossbar switch networks for two industrial strength SoC designs.