On-chip network evaluation framework

Abstract

With the number of cores on a chip continuing to increase, proper evaluation of on-chip network is critical for not only network performance but also overall system performance. In this paper, we show how a network-only simulation can be limited as it does not provide an accurate representation of system performance. We evaluate traditionally used openloop simulations and compare them to closed-loop simulations. Although they use different methodologies, measurements, and metrics, we identify how they can provide very similar results. However, we show how the results of closed-loop simulations do not correlate well with execution-driven simulations. We then add simple extensions to the closed-loop simulation to model the impact of the processor and the memory system and show how the correlation with execution-driven simulations can be improved. The proposed framework/methodology provides a fast simulation time while providing better insights into the impact of network parameters on overall system performance.