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# Library prosa.model.task.preemption.fully_nonpreemptive

Require Export prosa.model.task.preemption.parameters.

# Fully Non-Preemptive Task Model

In this module, we instantiate the task model in which jobs cannot be preempted once they have commenced execution.
Section FullyNonPreemptiveModel.
Consider any type of tasks with WCET bounds.
Context {Task : TaskType}.
Context `{TaskCost Task}.
In the fully non-preemptive model, no job can be preempted until its completion. The maximal non-preemptive segment of a job j has length job_cost j, which is bounded by task_cost tsk.
Definition fully_nonpreemptive_task_model : TaskMaxNonpreemptiveSegment Task :=
{|
task_max_nonpreemptive_segment := task_cost
|}.
End FullyNonPreemptiveModel.

## Run-to-Completion Threshold

In this section, we instantiate the task-level run-to-completion threshold for the fully non-preemptive model.
Section TaskRTCThresholdFullyNonPreemptive.
Consider any type of tasks.
Context {Task : TaskType}.
In the fully non-preemptive model, no job can be preempted prior to its completion. In other words, once a job starts running, it is guaranteed to finish. Thus, we can set the task-level run-to-completion threshold to ε.
#[local] Instance fully_nonpreemptive_rtc_threshold : TaskRunToCompletionThreshold Task :=
{
task_rtct := constant ε
}.
End TaskRTCThresholdFullyNonPreemptive.