Schedulability analysis of dependent probabilistic realtime tasks The complexity of modern architectures has increased the timing variability of programs (or tasks). In this context, new approaches based on probabilistic methods are proposed to decrease the pessimism by associating probabilities to the worst case values of the programs (tasks) time execution. In this paper, we extend the original work of Chetto et al. 7 on precedence constrained tasks to the case of tasks with worst case execution times described by probability distributions. The precedence constraints between tasks are defined by acyclic directed graphs and these constraints are transformed in appropriate release times and deadlines. The new release times and deadlines are built using new maximum and minimum relations between pairs of probability distributions. We provide a probabilistic schedulability condition based on these new relations.

Scheduling Periodic and Aperiodic Tasks with Time, Energy Harvesting and Precedence Constraints on Multicore Systems Abstract   This paper deals with the realtime scheduling problem of multicore systems powered by renewable energy harvested from environment. They handle two types of software tasks which are mapped to cores statically and not allowed to migrate. A task can be periodic which may depend on other tasksxe2x80x99 results, or aperiodic which is added to the system to cope with external interruptions. The uncertainty of energy availability in energy harvesting systems makes realtime scheduling more challenging because energy constraints can be violated to ensure realtime performance. A novel scheduling strategy is proposed to effectively compute deadlines allowing for tasks and messages to meet related constraints. This method consists of two phases, i) the first one defines different time slots each of which is characterized by energy and frequency parameters to cope with the energy availability issue, and ii) the second one calculates the deadlines ensuring realtime system feasibility by considering the invocation of aperiodic task execution and task precedence constraints. The originality of the current work compared with related studies is that it deals with multicore, periodic and aperiodic tasks, dependency, energy harvesting, and realtime aspects simultaneously.