Safety analysis of timing properties in real-time systems
IEEE Transactions on Software Engineering - Special issue on reliability and safety in real-time process control
Scheduling real-time computations with separation constraints
Information Processing Letters
Design and implementation of Maruti-II
Advances in real-time systems
Scheduling of periodic tasks with relative timing constraints
Scheduling of periodic tasks with relative timing constraints
Allocation and scheduling of real-time periodic tasks with relative timing constraints
Allocation and scheduling of real-time periodic tasks with relative timing constraints
Parametric Dispatching of Hard Real-Time Tasks
IEEE Transactions on Computers
Distance-Constrained Scheduling and Its Applications to Real-Time Systems
IEEE Transactions on Computers
Parametric Scheduling for Network Constraints
COCOON '01 Proceedings of the 7th Annual International Conference on Computing and Combinatorics
Distributed algorithms for partially clairvoyant dispatchers
Cluster Computing
On the design and implementation of a shared memory dispatcher for partially clairvoyant schedulers
International Journal of Parallel Programming
Totally clairvoyant scheduling with relative timing constraints
VMCAI'06 Proceedings of the 7th international conference on Verification, Model Checking, and Abstract Interpretation
| Hi-index | 0.00 |
In some hard real-time systems, relative timing constraints maybe imposed on task executions, in addition to the release timeand deadline constraints. Relative timing constraints such asseparation or relative deadline constraints may be given betweenstart or finish times of tasks (Gerber et al., 1995; Han andLin, 1989; Han et al., 1992; Han and Lin, 1992; Han et al., 1996).One approach in real-time schedulingis to find a total order on a set of N tasks ina scheduling window, and cyclically use this order at run timeto execute tasks. However, in the presence of relative timingconstraints, if the task execution times are nondeterministicwith defined lower and upper bounds, it is not always possibleto statically assign task start times at pre-runtime for a giventask ordering (Gerber et al., 1995). We develop a technique called dynamic cyclic dispatching asan extension of a parametric dispatching mechanism in (Gerberet al., 1995). An ordered set of N tasks is assumedto be given in a scheduling window and this schedule(ordering)is cyclically repeated at runtime in consecutive scheduling windows.Relative timing constraints between tasks may be defined acrossscheduling window boundaries as well as within one schedulingwindow. A task set is defined to be dispatchable if there existsany way in which the tasks can be dispatched with all their timingconstraints satisfied. An off-line algorithm is presented tocheck the dispatchability of a task set and to obtain parametriclower and upper bound functions for task start times if the taskset is dispatchable. These parametric bound functions are evaluatedat runtime to obtain a valid time interval during which a taskcan be started. The complexity of this off-line component isshown to be O(n^2N^3) where n is thenumber of tasks in a scheduling window that have relative timingconstraints with tasks in the next scheduling window. An onlinealgorithm can evaluate these bounds in O(N) time.Unlike static approaches whichassign fixed start times to tasks in the scheduling window, ourapproach allows us to flexibly manage the slack times at runtimewithout sacrificing the dispatchability of tasks. Also, a widerclass of relative timing constraints can be imposed to the taskset compared to the traditional approaches.