Integrated Schedulers for a Predictable Interrupt Management on Real-Time Kernels

Abstract

To analyse the timeliness behaviour of a real-time system is one its key aspects. A big effort has been performed by the real-time community to develop accurate and more general schedulability analysis that can ensure the correct execution of the system. However, few works have analysed the side effects introduced by the scheduler and undesired execution of Interrupt Service Routines. Previous works addressed the interrupt interference by proposing an Integrated Interrupt Model that avoids unpredictable disturbance from external interrupts. Even so, the scheduling overhead due to the unnecessary activation of low priority tasks remains still unaddressed in this model. This work proposes a new Virtual implementation of an Integrated Interrupt Event-Driven Scheduler that copes with this pending issue. It also analyses the behaviour of the commonly used dual queue scheme under this kind of schedulers and proposes a more appropriated data structure to avoid unnecessary overheads.