Prof. Lucia Lo Bello, PhD

Publication type:  Conference Proceeding

Authors: J. L. Diaz, J. M. López, M. Garcia, A. M. Campos, K. Kim, L. Lo Bello

Conference: Proceedings of the 25th IEEE International Real-Time Systems Symposium (RTSS 2004)

Address: Lisbon, Portugal

Pages: 197–207

Date: Dec. 2004

Abstract:
The exact stochastic analysis of most real-time systems is becoming unaffordable in current practice. On one side, the exact calculation of the response time distribution of the tasks is not possible except for simple periodic and independent task sets. On the other side, in practice, tasks introduce complexities like release jitter, blocking in shared resources, stochastic dependencies, etc, which can not be handled by the periodic and independent task set model. This paper introduces the concept of pessimism in the stochastic analysis of real-time systems in the following sense: the exact probability of missing any deadline is always lower than that derived from the pessimistic analysis. Therefore, if real-time constraints are expressed as probabilities of missing deadlines, the pessimistic stochastic analysis provides safe results. Some applications of the pessimism concept are presented. Firstly, the practical problems that arise in the stochastic analysis of periodic and independent task sets are addressed. Secondly, we extend to the stochastic case some well known techniques of the deterministic analysis, such as the blocking in shared resources, and the task priority assignment.

Keywords: Stochastic systems; Real-time systems; Stochastic analysis

Publisher: IEEE

DOI:  10.1109/REAL.2004.41

URL:  https://ieeexplore.ieee.org/document/1381307

Status: published

Cite as:
 J. L. Diaz, J. M. López, M. Garcia, A. M. Campos, K. Kim, L. Lo Bello, "Pessimism in the stochastic analysis of real-time systems: Concept and applications", Proceedings of the 25th IEEE International Real-Time Systems Symposium (RTSS 2004) , pp. 197–207, Lisbon, Portugal, Dec. 2004

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