Providing throughput guarantees in mixed-criticality networks-on-chip

Future mixed-criticality systems must handle a growing variety of traffic requirements, ranging from safety-critical real-time traffic to bursty latency-sensitive best-effort traffic. Additionally, safety standards (e.g. ISO 26262) require sufficient independence among different criticality levels for mixed-criticality systems. Networks-on-Chip (NoCs), as a scalable and modular interconnect, are used as a promising solution for such systems. Hence, a NoC must provide performance isolation for safety-critical traffic and low latency for best-effort traffic at the same time. This paper presents a run-time configurable NoC design enabling throughput guarantees for selected traffic streams with reduced adverse impact on the performance of best-effort traffic. In contrast to existing approaches, we prioritize best-effort over guaranteed throughput traffic and only switch priorities when required, providing sufficient performance isolation among different criticality levels. We show that the overhead implementing our approach is affordable. And through an experimental evaluation, we show that the approach reduces the adverse effects through strict prioritization on best-effort applications.