Improvement of HLA/RTI real-time performance by scheduling periodic and aperiodic tasks

In order to apply high level architecture (HLA) in some real time systems, real-time performance of run-time infrastructure (RTI) must be guaranteed. Because of precedence constraints of correlated tasks between federates, it is hard to provide predictable response for all tasks, and it is also difficult to ensure the real-time performance of all tasks, especially aperiodic ones. The double-earliest deadline first (D-EDF) strategy of how to schedule overall periodic and aperiodic tasks inside a federate was discussed from the point view of task scheduling theory. The policy can not only discard some redundant data to ensure the periodic tasks completed effectively before their deadlines, but also schedule aperiodic ones running regularly to improve their real-time responding speed. It makes the system effectively handle the tasks with precedence constraints and consequently improves the real-time performance of RTI. The feasibility of the D-EDF scheduling strategy was proved.