Elastic Scheduling of Parallel Real-Time Tasks with Discrete Utilizations
James Orr, Johnny Wilfredo Condori Uribe, Chris Gill, Sanjoy Baruah, Kunal Agrawal, Shirley J. Dyke, Arun Jai Prakash, Iain Bate, Christopher Wong, Sabina Adhikari · 2020
Elastic scheduling allows for online adaptation of real-time tasks' utilizations (via manipulation of each task's computational workload or period) in order to maintain system schedulability in case the utilization demand of one or more tasks changes. This is done currently by assigning each task a utilization (and therefore period or workload) from within a continuous range of acceptable values. While this works well for anytime tasks whose quality of service improves with duration or for tasks that can run at any rate within a given range, many computationally-elastic tasks have a specific workload for each distinct mode of operation and therefore cannot perform arbitrary amounts of work. Similarly, some period-elastic tasks must run at specific (e.g. harmonic) rates. Therefore, a discrete set of candidate utilizations per task must be accommodated in such cases.