You are required to read and agree to the below before accessing a full-text version of an article in the IDE article repository.

The full-text document you are about to access is subject to national and international copyright laws. In most cases (but not necessarily all) the consequence is that personal use is allowed given that the copyright owner is duly acknowledged and respected. All other use (typically) require an explicit permission (often in writing) by the copyright owner.

For the reports in this repository we specifically note that

  • the use of articles under IEEE copyright is governed by the IEEE copyright policy (available at

  • the use of articles under ACM copyright is governed by the ACM copyright policy (available at

  • technical reports and other articles issued by M‰lardalen University is free for personal use. For other use, the explicit consent of the authors is required

  • in other cases, please contact the copyright owner for detailed information

By accepting I agree to acknowledge and respect the rights of the copyright owner of the document I am about to access.

If you are in doubt, feel free to contact

Improving the Schedulability of Real Time Systems under Fixed Preemption Point Scheduling


Publication Type:

Licentiate Thesis


During the past decades of research in Real-Time systems, non-preemptive scheduling and fully preemptive scheduling have been extensively investigated, as well as compared with each other. However, it has been shown that none of the two scheduling paradigms dominates over the other in terms of schedulabil- ity. In this context, Limited Preemptive Scheduling (LPS) has emerged as an attractive alternative with respect to, e.g., increasing the overall system schedu- lability, efficiently reducing the blocking by lower priority tasks (compared to non-preemptive scheduling) as well as efficiently controlling the number of preemptions, thus controlling the overall preemption-related delay (compared to fully-preemptive scheduling). Several approaches within LPS enable the above mentioned advantages. In our work, we consider the Fixed Preemption Point Scheduling (LP-FPP) as it has been proved to effectively reduce the preemption-related delay compared to other LPS approaches. In particular, LP-FPP facilitates more precise estimation of the preemption-related delays, since the preemption points of a task in LP-FPP are explicitly selected during the design phase, unlike the other LPS approaches where the preemption points are determined at runtime. The main goal of the proposed work is to improve the schedulability of real-time systems under the LP-FPP approach. We investigate its use in different domains, such as: single core hard real-time systems, partitioned multi-core systems and real-time systems which can occasionally tolerate deadline misses. We enrich the state of the art for the single core hard real-time systems by proposing a novel cache-related preemption delay analysis, towards reducing the pessimism of the previously proposed methods. In the context of partitioned multi-core scheduling we propose a novel partitioning criterion for the Worst-Fit Decreasing based partitioning, and we also contribute with the comparison of existing partitioning strategies for LP-FPP scheduling. Finally, in the context of real-time systems which can occasionally tolerate deadline misses, we contribute with a probabilistic response time analysis for LP-FPP scheduling and a preemption point selection method for reducing the deadline-misses of the tasks


author = {Filip Markovic},
title = {Improving the Schedulability of Real Time Systems under Fixed Preemption Point Scheduling},
month = {September},
year = {2018},
url = {}