Runtime QoS support for MPSoC: A processor centric approach

The MPSoC literature related to runtime support of Quality of Service (QoS) presents proposals related to the management of the interconnection infrastructure and the processing elements (PEs). The QoS management of computation resources is essential to fulfill real-time (RT) applications, as in multimedia systems, where dynamic workload and CPU sharing are commonplace. However, few works concerning QoS at the processor level for RT applications are found in the literature. The proposed work provides a runtime support for QoS acting in the PEs, coupled to a monitoring scheme at the task level. The main goal of the present work is to employ a low overhead task migration combined with task scheduling priority, to increase the computation resources for RT applications. An important feature of the proposal is to act indirectly over the QoS application, by minimizing the interference of the best effort (BE) tasks in the RT application performance. If the monitoring infrastructure still detects deadline misses, the system management then tries to optimize the RT application acting at the task level, migrating the affected RT task or modifying the scheduling policy. The NoC-based MPSoC was modeled and validated using an RTL description, with real applications. Results use throughput as the reference performance parameter. The proposed technique restored the RT applications performance after the introduction of disturbing applications, with a small reaction time.