A design flow for application specific heterogeneous pipelined multiprocessor systems

This paper describes a rapid design methodology to create a pipeline of processers to execute streaming applications. The methodology is in two separate phases: the first phase, uses a heuristic to rapidly search through a large number of processor configurations (configurations differ by the base processor, the additional instructions and cache sizes) to find the near Pareto front; the second phase, utilizes either the above heuristic or an ILP (Integer Linear Programming) formulation to search a smaller design space to find an appropriate final implementation. By the utilization of the fast heuristic with differing runtime constraints in the first phase, we rapidly find the near Pareto front. The second phase provides either an optimal or a near optimal solution. Both the ILP formulation and the heuristic find a system with the smallest area, within a designer specified runtime constraint. The system has efficiently explored design spaces with over 10¹² design points.

We integrated this design methodology into a commercial design flow and evaluated our approach with different benchmarks (JPEG Encoder, JPEG Decoder and MP3 Encoder). For each benchmark, the near Pareto front was found in a few hours using the heuristic (took several days for the ILP). The results show that the average area error of the heuristic is within 2.5% of the optimal design points (obtained using ILP) for all benchmarks.