Timing Analysis of Cause-Effect Chains with Heterogeneous Communication Mechanisms

Abstract

Software applications in automotive systems are comprised of communicating real-time tasks, described by cause-effect chains. To guarantee functional correctness, it is mandatory to verify end-to-end timing latencies of the cause-effect chains. The analysis of end-to-end latencies highly depends on the communication method. Implicit communication is standardized in the AUTOSAR Timing Specification and ensures data consistency. To abstract communication from the actual execution behavior of tasks, logical execution time (LET) has been proposed. However, the determinism that is provided by LET comes at the cost of increased end-to-end latencies. In industry-grade systems, periodic and sporadic tasks using LET and implicit communication co-exist. Hence, end-to-end latency analyses should cover such heterogeneous cause-effect chains.