Sufficient Response Time Analysis Considering Dependencies Between Rate-Dependent Tasks
Timo Felda and Frank Slomkab
Institute of Embedded Systems/Real-Time Systems Ulm University, 89069 Ulm, Germany.
In automotive embedded real-time systems, such as the engine control unit (ECU), some tasks are activated whenever the engine arrives at a specific angular position. In consequence, the frequency at which this task is activated changes with the speed of the engine i. e. angular velocity. Additionally, these tasks have worst case execution times and deadlines that also depends on the angular velocity. Such tasks exhibit ratedependent behaviour.
In recently published works analytical methods for tasks with this rate-dependent behaviour were introduced. Though those methods do not consider dependencies between tasks. For instance one event might be displaced a certain angular position after an event of another task. In this paper, a sufficient analysis will be introduced, which considers those dependencies to improve the accuracy of existing methods.
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