RWTH Aachen University
In this paper, the authors outline the Adaptive Resource Allocation Protocol (ARAP) as an improved resource synchronization algorithm for hierarchically scheduled real-time systems. ARAP exploits knowledge about task utilization, using a Proportional-Integral-Derivative (PID) controller, to estimate required resource bandwidth and improve scheduling decisions. Their analysis and experiments with RTSIM (Real-Time System SIMulator) show that ARAP provides better temporal isolation and resource utilization during periods of transient overload compared to state-of-the-art resource synchronization algorithms. Implemented as part of VxWorks, the results are confirmed using an avionic system, for which ARAP substantially reduced the number of hard real-time deadline, misses.