Scheduling multiple task graphs with end-to-end deadlines in distributed real-time systems utilizing imprecise computations

In order to meet the inherent need of real-time applications for high quality results within strict timing constraints, the employment of effective scheduling techniques is crucial in distributed real-time systems. In this paper, we evaluate by simulation the performance of strategies for the dynamic scheduling of composite jobs in a homogeneous distributed real-time system. Each job that arrives in the system is a directed acyclic graph of component tasks and has an end-to-end deadline. For each scheduling policy, we provide an alternative version which allows imprecise computations, taking into account the effects of input error on the processing time of the component tasks of a job. The simulation results show that the alternative versions of the algorithms outperform their respective counterparts. To our knowledge, an imprecise computations approach for the dynamic scheduling of multiple task graphs with end-to-end deadlines and input error has never been discussed in the literature before.