I have some tasks, which are further divided into runnables. Runnables execute as task instances. Runnables have dependencies within the tasks and also to other tasks's runnables. I have the information of deadlines and periods of tasks and the execution order of tasks and runnables i.e I can extract the data flow but the only point where I am stucking is that how can I get the information IF the task instances are executing within the period i.e obeying the deadlines and if not executing withtin the deadline then that task instance will execute in the next cycle or next period.
Any ideas ? Suggestions ?
p.s I dont have timing information for the execution of runnables.
Well, lets suppose there are two tasks Task_A and Task_B. Both tasks have runnables which reads values from other runnables. e.g runnable_A10(belongs to Task_A) may read the value from runnable_A2(belongs to same task, Task_A) or it may also read value from runnable_B2(belongs to Task_B) .. This is how the dependency is defined among runnables.
There is no OS or code until now, just trying to think out of the box if it is possible to get the timing information of runnables wheter they are executing within the deadline of the task or they are being executed in the next period of the task. One possible option is to do Zero Execution Timing analysis . But then again there is no exact execution time of runnables soooo, my question was is their any other possible option where you can say if the runnables (which acts as task instances) are obeying timing constraints of tasks ?
I am not certain I clearly understand your question. From what I get, you should perform Worst Case Execution Time (WCET) analysis on the code of your runnables, which gives you a conservative estimate of the worst possible execution time of your runnables. Then using this, you must define or choose a scheduling policy (unless you are working with an OS which imposes one). Such policies include Rate Monotonic, Deadline Monotonic, Earliest Deadline First etc. and usually come with analytic criterion which help you figure out if your system is schedulable in the worst case under these policies (i.e. if any possible execution of your system respects the timing constraints placed on your tasks). Usually, such criterion work only for task systems without dependencies between the task instances, but there also exist techniques that allow you to build schedules (or test the schedulability of the system) even in the presence of dependencies. If you want I can point you to some publications tackling this problem of real-time scheduling with dependencies.
I hope this will help you.
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