An Iterative Computational Technique for Performance Evaluation of Networks-on-Chip

The trend toward integrated many-core architectures makes the network-on-chip (NoC) technology, the on-chip communication infrastructure of choice. However, and as opposed to a simple bus, due to its distributed and complex nature in terms of topology, wire size, routing algorithm, and so on, the timing behavior and thus performance of the infrastructure is difficult to predict. Therefore, one of the important phases in the NoC design flow is performance evaluation, which is to extract performance metrics to verify whether a specific instance from the NoC design space satisfies the requirements of the entire system. In this sense, reducing the time to obtain the NoC performance and consequently speeding-up the design space exploration is one of the keys that can considerably reduce the design-flow time and cost. In an effort toward this direction, we propose in this paper a novel analytical performance evaluation method that can be used in the earliest stages of the design flow, before using time-consuming simulations. The analytical method is used to evaluate the performance of a general purpose NoC and we show that it can predict the router latency, end-to-end per-flow latency, and network saturation point with an accuracy comparable to a cycle-accurate simulation. To systematically analyze the accuracy of our method compared to the corresponding simulation model, we present also an innovative accuracy analysis method.