Implications of architecture and implementation choices on timing analysis of automotive CAN networks

Abstract

The Controller Area Network (CAN) protocol is widely adopted in industry such as automotive. It has been analyzed in a number of studies in the real-time systems community to compute the worst case response time of messages, based on an ideal model on the behavior of the message queuing and CAN controller. Recently, more results are being added to study systems that are not constructed according to the ideal model.

In this paper, we further investigate the architecture choices that may affect the timing analysis. Specifically, we provide an assessment on the practical relevance of several analysis results. We also present theory and empirical studies on the relative importance of architecture implementation issues that are quite common in real systems but further deviate from the ideal behavior. We also experimentally evaluate the response time while using TxObjects without preemption. We propose a heuristic for the design of multiple software queues when TxObjects are not preemptable. Finally, we derive an upper bound on the worst case response time when message output at the CAN driver is polling based.