Towards Fully Jitterless Applications: Periodic Scheduling in Multiprocessor MCSs Using a Table-Driven Approach

Abstract

In mixed criticality systems (MCSs), the time-triggered scheduling approach focuses on a special case of safety-critical embedded applications which run in a time-triggered environment. Sometimes, for these types of MCSs, perfectly periodical (i.e., jitterless) scheduling for certain critical tasks is needed. In this paper, we propose FENP_MC (Fixed Execution Non-Preemptive Mixed Criticality), a real-time, table-driven, non-preemptive scheduling method specifically adapted to mixed criticality systems which guarantees jitterless execution in a mixed criticality time-triggered environment. We also provide a multiprocessor version, namely, P_FENP_MC (Partitioned Fixed Execution Non-Preemptive Mixed Criticality), using a partitioning heuristic. Feasibility tests are proposed for both uniprocessor and homogenous multiprocessor systems. An analysis of the algorithm performance is presented in terms of success ratio and scheduling jitter by comparing it against a time-triggered and an event-driven method in a non-preemptive context.

Multi-Core Time-Triggered OCBP-Based Scheduling for Mixed Criticality Periodic Task Systems

“…In event-driven scheduling, the scheduling points are defined by task completion and task arrival events [ 8 ]. Some examples of event-driven schedulers are [ 9 , 10 , 11 , 12 , 13 ].…”

“…For multiprocessor platforms, a method is described in [ 11 ] based on setting virtual deadlines from any feasible fluid rates, while in [ 12 ], a fluid-based algorithm was implemented, which allows tasks to execute on the same processor simultaneously. In [ 13 ], a semi-partitioned mixed criticality method is presented, which offers low criticality task migration from one processor to another once mode switch occurs, in order to improve the service of low criticality tasks in the high criticality mode.…”

“…Our time-triggered algorithm offers complete determinism and isolation between components of different criticalities in comparison to the event-driven multiprocessor algorithms described previously [ 11 , 12 , 13 ]. This ensures the certification of high criticality functionalities under very conservative assumptions.…”