On the Criticality of Probabilistic Worst-Case Execution Time Models

Santinelli, Luca; Guo, Zhishan

doi:10.1007/978-3-319-69483-2_4

Cited by 6 publications

(5 citation statements)

References 20 publications

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“…Some authors apply GoF tests to check if the observations comply with the i.i.d. criteria, such as Kolmogorov-Smirnoff [4,12,44], Anderson-Darling [2,4], Wald-Wolfowitz [4,12], Ljung-Box [2,5] among others [40,41]. However, this action is not mandatory and can be questionable, since there are situations where data meet the i.i.d.…”

Section: Samplingmentioning

confidence: 99%

“…Basic concepts and related challenges to use EVT for pWCET inference have been reported [9,10,13,20,42]. Positive results have been obtained in simulated [32], single-core [4,33,41] and other platforms [5,25]. Some publications have investigated problems and specific characteristics for applying EVT in the domain of timing analysis, such as determining sample sizes [44], issues of representativeness or problems related with dependencies in the collected samples [22,37,40].…”

Section: Introductionmentioning

confidence: 99%

“…There are results focused on evaluating choices between EVT models or specific distributions [8,24,34,39]. Studies on other specific aspects have been reported, which include modeling dependencies via copulas [6,36,37], the use of Goodness-of-Fit (GoF) tests [12,19,38] or specific improvements [41].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On vulnerabilities in EVT-based timing analysis: an experimental investigation on a multi-core architecture

Vasconcelos,

Lima,

Wehaiba El Khazen

et al. 2023

Des Autom Embed Syst

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Hardware architectures based on multiple cores, cache memory and branch prediction usually preclude the application of classical methods for determining execution time bounds for real-time tasks. As such bounds are fundamental in the designing of real-time systems, Measurement-Based Probabilistic Timing Analysis (MBPTA) has been employed. A common choice is the derivation of probabilistic Worst-Case Execution Time (pWCET) via the use of Extreme Value Theory (EVT), a branch of statistics used to estimate the probability of rare events that are more extreme than observations. However, pWCET estimations are usually reported in a controlled or simulated environment. In this paper we apply MBPTA in a real multi-core platform, namely Raspberry Pi 3B, taking into consideration possible interference due to operating system and concurrent activities. The results indicate that although EVT is effective, it does not always produce adequate models and coherent pWCET estimations. As MBPTA is primarily called for when classical methods are not applicable, as it is the case for the studied platform, the results reported in this paper highlight risks and vulnerabilities when applying MBPTA-EVT for pWCET inference * .

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Section: Samplingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On vulnerabilities in EVT-based timing analysis: an experimental investigation on a multi-core architecture

Vasconcelos,

Lima,

Wehaiba El Khazen

et al. 2023

Des Autom Embed Syst

View full text Add to dashboard Cite

show abstract

“…Draskovic et al [49] introduced a new probabilistic model for mixed-criticality systems; safety metrics are defined, and an analysis is developed to quantify safety levels according to the considered criticality level. Santinelli and Guo [50] discussed the accuracy and the flexibility of probabilistic models as advantages for mixed-criticality schedulability analysis in efficient resource usage. Davis and Cucu-Grosjean [51] depicted a survey of recent probabilistic scheduling approaches, with a dedicated section of the above introduced mixed-criticality scheduling approaches.…”

Section: Related Workmentioning

confidence: 99%

Mixed-Criticality Scheduling Upon Permitted Failure Probability and Dynamic Priority

Guo

Vaidhun

Satinelli

et al. 2022

IEEE Trans. Comput.-Aided Des. Integr. Circuits Syst.

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Many safety-critical real-time systems are considered certified when they meet failure probability requirements with respect to the maximum permitted incidences of failure per hour. In this article, the mixed-criticality task model with multiple worst case execution time (WCET) estimations is extended to incorporate such system-level certification restrictions. A new parameter is added to each task, characterizing the distribution of WCET estimations-the likelihood of all jobs of a task finishing their executions within the less pessimistic WCET estimates. Efficient algorithms are derived for scheduling mixed-criticality systems represented using this model for both uniprocessor and multiprocessor platforms for independent tasks. Furthermore, a 0/1 covariance matrix is introduced to represent the failure dependency between tasks. An efficient algorithm is proposed to schedule such failure-dependent tasks. Experimental analyses show our new model and algorithm outperform current state-of-the-art mixed-criticality scheduling algorithms.

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“…pWCET ordering via statistical dominance. In previous articles on probabilistic real-time [44,45], the ordering relation between pWCET has been defined by using the simplest form of partial ordering between distributions:…”

Section: Exploring the Region Of Acceptancementioning

confidence: 99%

Dealing with Uncertainty in pWCET Estimations

Reghenzani

Santinelli

Fornaciari

2020

ACM Trans. Embed. Comput. Syst.

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The problem of estimating a tight and safe Worst-Case Execution Time (WCET), needed for certification in safety-critical environment, is a challenging problem for modern embedded systems. A possible solution proposed in last years is to exploit statistical tools to obtain a probability distribution of the WCET. These probabilistic real-time analyses for WCET are however subject to errors, even when all the applicability hypotheses are satisfied and verified. This is caused by the uncertainties of the probabilistic-WCET distribution estimator. This article aims at improving the measurement-based probabilistic timing analysis approach providing some techniques to analyze and deal with such uncertainties. The so-called region of acceptance model based on state-of-the-art statistical test procedures is defined over the distribution space parameters. From this model, a set of strategies is derived and discussed, to provide the methodology to deal with the trade-off safety/tightness of the WCET estimation. These techniques are then tested over real datasets, including industrial safety-critical applications, to show the increased value of using the proposed approach in probabilistic WCET analyses.

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On the Criticality of Probabilistic Worst-Case Execution Time Models

Cited by 6 publications

References 20 publications

On vulnerabilities in EVT-based timing analysis: an experimental investigation on a multi-core architecture

On vulnerabilities in EVT-based timing analysis: an experimental investigation on a multi-core architecture

Mixed-Criticality Scheduling Upon Permitted Failure Probability and Dynamic Priority

Dealing with Uncertainty in pWCET Estimations

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