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Documents authored by Pollex, Victor

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DOI: 10.4230/LIPIcs.ECRTS.2025.16
Formal Comparison of Outgoing Event Streams Between Compositional Performance Analysis and Real-Time Calculus

Authors: Victor Pollex and Frank Slomka

Published in: LIPIcs, Volume 335, 37th Euromicro Conference on Real-Time Systems (ECRTS 2025)

Abstract
Real-time systems are required to produce correct responses which also need to be on time. Two methods to verify the timeliness of the results are the compositional performance analysis and the real-time calculus. Both methods use bounds as inputs from which they derive bounds for the timeliness. Therefore, it is preferable to have better bounds for the inputs. Any of these bounds may contain pessimism. Because both methods use a modular/compositional approach for distributed real-time systems, the pessimism in the bounds accumulate. Therefore, it is desirable to keep the pessimism as low as possible. In this work we investigate distributed real-time systems where tasks have an activation dependency, i. e., the activation of one task depends on the termination of a job of another task. Specifically, we compare the derived bound of how frequent the jobs of a task terminate and subsequently how frequent the activation dependent task activates and releases its jobs. Our contribution is a formal comparison of these bounds that the compositional performance analysis and the real-time calculus derive by means of a mathematical proof. We show that for identical inputs the real-time calculus derives a bound that is not worse than the bound that the compositional performance analysis derives for a single module/component. The mathematical proof also removes any uncertainty that existing empirical comparisons of these bounds may contain.
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Victor Pollex and Frank Slomka. Formal Comparison of Outgoing Event Streams Between Compositional Performance Analysis and Real-Time Calculus. In 37th Euromicro Conference on Real-Time Systems (ECRTS 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 335, pp. 16:1-16:25, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{pollex_et_al:LIPIcs.ECRTS.2025.16,
  author =	{Pollex, Victor and Slomka, Frank},
  title =	{{Formal Comparison of Outgoing Event Streams Between Compositional Performance Analysis and Real-Time Calculus}},
  booktitle =	{37th Euromicro Conference on Real-Time Systems (ECRTS 2025)},
  pages =	{16:1--16:25},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-377-5},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{335},
  editor =	{Mancuso, Renato},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2025.16},
  URN =		{urn:nbn:de:0030-drops-235945},
  doi =		{10.4230/LIPIcs.ECRTS.2025.16},
  annote =	{Keywords: compositional performance analysis, real-time calculus, outgoing event streams}
}
Document
DOI: 10.4230/LIPIcs.ECRTS.2022.7
A Mathematical Comparison Between Response-Time Analysis and Real-Time Calculus for Fixed-Priority Preemptive Scheduling

Authors: Victor Pollex and Frank Slomka

Published in: LIPIcs, Volume 231, 34th Euromicro Conference on Real-Time Systems (ECRTS 2022)

Abstract
Fixed-priority preemptive scheduling is a popular scheduling scheme for real-time systems. This is accompanied by a vast amount of research on how to analyse and check whether these systems satisfy their real-time requirements. Two methods that emerged from this research are the response-time analysis and the real-time calculus. These two methods have been compared empirically on the basis of several abstract systems showing that for some systems one method gives better results than the other and for other systems both methods appear to give the same results. However, empirical analyses inherently contain uncertainty. To get a definitive answer we compare both methods mathematically and we show that both methods give the same results for systems that use fixed-priority preemptive scheduling and independent tasks.
Cite as

Victor Pollex and Frank Slomka. A Mathematical Comparison Between Response-Time Analysis and Real-Time Calculus for Fixed-Priority Preemptive Scheduling. In 34th Euromicro Conference on Real-Time Systems (ECRTS 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 231, pp. 7:1-7:25, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

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@InProceedings{pollex_et_al:LIPIcs.ECRTS.2022.7,
  author =	{Pollex, Victor and Slomka, Frank},
  title =	{{A Mathematical Comparison Between Response-Time Analysis and Real-Time Calculus for Fixed-Priority Preemptive Scheduling}},
  booktitle =	{34th Euromicro Conference on Real-Time Systems (ECRTS 2022)},
  pages =	{7:1--7:25},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-239-6},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{231},
  editor =	{Maggio, Martina},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2022.7},
  URN =		{urn:nbn:de:0030-drops-163246},
  doi =		{10.4230/LIPIcs.ECRTS.2022.7},
  annote =	{Keywords: real-time systems, fixed-priority scheduling, response-time analysis, real-time calculus}
}
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