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Publication
Extending fixed task-priority schedulability by interference limitation
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Advisor(s)
Abstract(s)
While the earliest deadline first algorithm is known to be
optimal as a uniprocessor scheduling policy, the implementation
comes at a cost in terms of complexity. Fixed taskpriority
algorithms on the other hand have lower complexity
but higher likelihood of task sets being declared unschedulable,
when compared to earliest deadline first (EDF). Various
attempts have been undertaken to increase the chances of
proving a task set schedulable with similar low complexity.
In some cases, this was achieved by modifying applications
to limit preemptions, at the cost of flexibility. In this work,
we explore several variants of a concept to limit interference
by locking down the ready queue at certain instances. The
aim is to increase the prospects of schedulability of a given
task system, without compromising on complexity or flexibility,
when compared to the regular fixed task-priority algorithm.
As a final contribution, a new preemption threshold
assignment algorithm is provided which is less complex and
more straightforward than the previous method available in
the literature.
Description
Keywords
Dual priority scheduling Non-preemptive scheduling Real-time scheduling