Response time calculations for non-preemptive tasks with variable execution time

This paper presents an efficient exhaustive enumeration technique, which can be applied to the non-preemptive scheduling for tasks and messages. Our investigated method calculates best and worst case response times for periodic and aperiodic tasks scheduled on a single processor without preemption and with variable execution time. Response time analysis for non-preemptive tasks is relatively limited on computations of the worst case response time with fixed execution time duration. Worst-case response time is computed assuming maximum execution time and critical instant release. Hence to obtain an exhaustive computational method based on a suitable data structure we investigated an algorithmic method that deals efficiently with asynchronous release and non-fixed execution duration. Our algorithm calculates response times and thereby verifying that deadlines can be met or not. Obtained results are different from previous results obtained when assuming an optimist and pessimist interference conditions between tasks or messages.