ECTM: A network-on-chip communication model to combine task and message schedulability analysis

Abstract Network-on-Chips (NoC) are widely used in industrial applications since they provide communication parallelism and reduce energy consumption. The use of NoC has been recently extended to real-time systems, whose execution has to meet temporal constraints. Communication delays introduced by the network make the scheduling analysis challenging. In this article, we propose a new NoC communication model called ECTM . The main goal of this model is to assess the schedulability of dependent periodic tasks exchanging messages on a NoC. ECTM is a model allowing schedulability analysis of messages and tasks of the NoC. To achieve schedulability, ECTM produces an analysis model by transforming NoC messages to tasks in order to take into account communication delays during the scheduling analysis. Schedulability of the system is assessed using simulation over the feasibility interval with a list scheduling, ECTM supports Store-And-Forward and Wormhole NoC. In this article, we have demonstrated the correctness of the transformations of ECTM. ECTM has been implemented in a real-time scheduling analysis tool called Cheddar and we performed experiments to assess its efficiency. ECTM is more efficient than existing solutions with an improvement of 30% for Store-And-Forward NoCs and up to 100% for Wormhole NoCs, while the proposed model requires a larger computation time about 17% for Store-And-Forward NoCs.