Multi-Layer Diagnosis for Fault-Tolerant Networks-on-Chip

In order to tolerate faults that emerge in operating Networks-on-Chip, diagnosis techniques are employed for fault detection and localization. On various network layers, diverse diagnosis methods can be employed which differ in terms of their impact on network performance (e.g., by operating concurrently versus pre-empting regular network operation) and the quality of diagnostic results. In this contribution, we show how diagnosis techniques of different network layers of a Network-on-Chip can be combined into multi-layer solutions. We present the cross-layer information flow used for the interaction between the layers and show the resulting benefit of the combination compared to layer-specific diagnosis. For evaluation, we investigate the diagnosis quality and the impact on system performance to explore the entire design space of layer-specific techniques and their multi-layer combinations. We identify pareto-optimal combinations that offer an increase of system performance by a factor of four compared to the single-layer diagnosis.