A message-level monitoring protocol for QoS flows in NoCs

This work proposes a traffic monitoring scheme to be applied to NoCs. Current schemes transmit monitoring traffic to one or more MSA (Monitoring Service Access Point), and such MSAs are responsible to take some action, as task migration and fault detection. The proposed monitoring method is flow-oriented, i.e, it works at the message-level, and traffic congestion is evaluated all along the source-target path. It can be applied to different adaptation methods as adaptive routing, task migration and dynamic task mapping. Traffic information of QoS flows is stored in tables located at each router. Traffic initiators indicate the routers of the QoS flow path that should be monitored. MSAs are placed in targets of QoS traffic, and notify to the traffic source the occurrence of congestion. DATA packets are used to transmit both application data and monitoring traffic. Presented results evaluate the method in terms of area overhead, and precision/reactivity to congestion events, associated to an adaptive source routing algorithm.