Tractable real-time schedulability analysis for mode changes under temporal isolation

Abstract

Real-time multimedia subsystems often require support for switching between different resource and application execution modes. To ensure that timing constraints are not violated during or after a subsystem changes mode, real-time schedulability analysis is required. However, existing time-efficient multi-mode schedulability analysis techniques for application-only mode changes are not appropriate for subsystems that require changes in the resource execution behavior (e.g., processors with dynamic power modes). Furthermore, all existing multi-mode schedulability analysis that handles both resource and application mode changes is highly exponential and not scalable for subsystems with a moderate or large number of modes. We address the lack of tractable schedulability analysis for such subsystems by proposing a model for characterizing multiple resource and application modes and by deriving a sufficient schedulability test that has pseudo-polynomial time complexity. Simulation results show that our proposed schedulability test, when compared with previously-proposed approaches, requires significantly less time and is just as precise.