Bounding Deadline Misses in Weakly-Hard Real-Time Systems with Task Dependencies

Zain A. H. Hammadeh1,a, Rolf Ernst1,b, Sophie Quinton2, Rafik Henia3,c and Laurent Rioux3,d
1TU Braunschweig, Germany.
2Inria Grenoble, France.
3Thales Research & Technology, France.


Real-time systems with functional dependencies between tasks often require end-to-end (as opposed to task-level) guarantees. For many of these systems, it is even possible to accept the possibility of longer end-to-end delays if one can bound their frequency. Such systems are called weakly-hard.
In this paper we provide end-to-end deadline miss models for systems with task chains using Typical Worst-Case Analysis (TWCA). This bounds the number of potential deadline misses in a given sequence of activations of a task chain. To achieve this we exploit task chain properties which arise from the priority assignment of tasks in static-priority preemptive systems. This work is motivated by and validated on a realistic case study inspired by industrial practice and derived synthetic test cases.

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