Combining EDF and FP Scheduling: Analysis and Implementation in Ada 2005
Ada-Europe '09 Proceedings of the 14th Ada-Europe International Conference on Reliable Software Technologies
A comparative study of rate monotonic schedulability tests
The Journal of Supercomputing
Optimal task execution times for periodic tasks using nonlinear constrained optimization
The Journal of Supercomputing
Optimising task layout to increase schedulability via reduced cache related pre-emption delays
Proceedings of the 20th International Conference on Real-Time and Network Systems
Lowest priority first based feasibility analysis of real-time systems
Journal of Parallel and Distributed Computing
Explicit reservation of cache memory in a predictable, preemptive multitasking real-time system
ACM Transactions on Embedded Computing Systems (TECS)
Bandwidth allocation for fixed-priority-scheduled compositional real-time systems
ACM Transactions on Embedded Computing Systems (TECS)
A review of fixed priority and EDF scheduling for hard real-time uniprocessor systems
ACM SIGBED Review - Special Issue on the 3rd Embedded Operating System Workshop (EWiLi 2013)
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Efficient exact schedulability tests are required both for on-line admission of applications to dynamic systems and as an integral part of design tools for complex distributed real-time systems. This paper addresses performance issues with exact Response Time Analysis (RTA) for fixed priority pre-emptive systems. Initial values are introduced that improve the efficiency of the standard RTA algorithm (i) when exact response times are required, and (ii) when only exact schedulability need be determined. The paper also explores modifications to the standard RTA algorithm, including; the use of a response time upper bound to determine when exact analysis is needed, incremental computation aimed at faster convergence, and checking tasks in reverse priority order to identify unschedulable tasksets early. The various initial values and algorithm implementations are compared by means of experiments on a PC recording the number of iterations required, and execution time measurements on a real-time embedded microprocessor. Recommendations are provided for engineers tasked with the problem of implementing exact schedulability tests, as part of on-line acceptance tests and spare capacity allocation algorithms, or as part of off-line system design tools.