Scheduling of Systems With Mixed-Criticality Requirements
Name
Zahra Jafari
Abstract
Traditional scheduling approaches waste utilization because they need to reserve absolute Worst Case Execution Time (WCET) for all tasks. However, in typical applications many tasks are executed much faster and have only soft deadlines. Such tasks are usually referred to as non-critical tasks. Hence, we have to take this into account while scheduling applications and in this thesis we introduce a scheduling approach that can schedule tasks with various criticalities. Apparently the predicted execution time for non-critical tasks should be less pessimistic than critical ones. Different priority functions may also be used to solve underutilization problem. In this thesis our concentration is on bringing mixed criticality into scheduling of the applications, executed on network-on-chip based systems. First of all we will illustrate an offline partitioning list scheduling. Later we explore the introduced mixed critical system with the impact of various priority functions and execution time models on the scheduling results. In our experiments we have used two levels of criticality and the goal is to guarantee the schedulability for the critical tasks and schedule the none-critical tasks in a best effort manner. In case the resources would be insufficient and a task would be possibly dropped or miss the deadline, the critical tasks are always guaranteed to meet their deadline.
Graduation Thesis language
English
Graduation Thesis type
Master - Software Engineering
Supervisor(s)
Gert Jervan
Defence year
2013