Towards Adaptive Hierarchical Scheduling

Hierarchical scheduling provides predictable timing and temporal isolation; two properties desirable in real-time embedded systems. In hierarchically scheduled systems, subsystems should receive a sufficient amount of CPU resources in order to be able to guarantee timing constraints of its internal parts (tasks). In static systems, an exact amount of CPU resource can be allocated to a subsystem. However, in dynamic systems, where execution times of tasks vary considerably during run-time, it is desirable to give a dynamic portion of the CPU given the current load situation. In this thesis we present a feedback control approach for adapting the amount of CPU resource that is allocated to subsystems during run-time such that each subsystem receives sufficient resources while keeping the number of deadline violations to a minimum. We also show some example simulations where the controller adapts the budget of a subsystems.

Autorentext

Nima Moghaddami Khalilzad is a PhD student at Mälardalen University since May 2011. He received his B.Sc. in software engineering from Arak University (Iran) in 2009. Afterwards, he started the master program in intelligent embedded systems at Mälardalen University and received his M.Sc. in computer science from this university in 2011.