optiMap: a tool for automated generation of NoC architectures using multi-port routers for FPGAs

Networks-on-chip (NoC) way of system design has been introduced to overcome the communication and the performance bottlenecks of a bus based system design. Area is at a premium in FPGAs. In this research, we propose to reduce network area overhead by reducing the number of routers, by making the router handle multiple logic cores. We implement an improved multi-local port router design with variable number of local ports. In addition to substantial area savings, we observe significant performance improvement. We discuss the issues involved in the use of multi-local port routers for NoC design in FPGAs. We observe an average of 36% area savings (maximum of 47.5%) on XC2VP30 FPGA and significant performance gain (30% average compared to single-local port version) with a multi-local port router. Mapping of cores onto such a non-traditional NoC architecture is a complex task. We present an algorithm which optimally maps the cores based on the given set of objectives. For the given task graph and the set of constraints, the algorithm finds the optimal number of routers, configuration of each router, optimal mesh topology and the final mapping. We test the algorithm on a wide variety of benchmarks and report the results