Complete worst-case execution time analysis of straight-line hard real-time programs

Stappert, Friedhelm; Altenbernd, P.

doi:10.1016/s1383-7621(99)00010-7

Cited by 89 publications

(46 citation statements)

References 21 publications

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“…[SA00] uses symbolic execution on the source code level to derive flow information. aiT's loop-bound analysis, see Section 6.1, is based on a combination of an interval-based abstract interpretation and pattern-matching working on the machine code.…”

Section: Control-flow Analysismentioning

confidence: 99%

The worst-case execution-time problem—overview of methods and survey of tools

Wilhelm

Engblom²,

Ermedahl

et al. 2008

ACM Trans. Embed. Comput. Syst.

1,468

1,029

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Abstract. The determination of upper bounds on execution times, commonly called WorstCase Execution Times (WCETs), is a necessary step in the development and validation process for hard real-time systems. This problem is hard if the underlying processor architecture has components such as caches, pipelines, branch prediction, and other speculative components. This article describes different approaches to this problem and surveys several commercially available tools and research prototypes.

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Section: Control-flow Analysismentioning

confidence: 99%

The worst-case execution-time problem—overview of methods and survey of tools

Wilhelm

Engblom²,

Ermedahl

et al. 2008

ACM Trans. Embed. Comput. Syst.

1,468

1,029

View full text Add to dashboard Cite

show abstract

“…Consequently, various solutions for the low-level analysis of individual path fragments in the presence of caches, pipelines, and branch predictors were proposed (Li and Malik 1999;Lundqvist andStenström 1998, 1999;Stappert and Altenbernd 2000;Theiling and Ferdinand 1998;Schneider and Ferdinand 1999;Ferdinand et al 1999;Colin and Puaut 2000). In contrast to these model-based approach, measurement-based timing analysis (MBTA) proposed the use of timed execution traces of individual code constituents obtained runs of the code on the target hardware (Bernat et al 2002(Bernat et al , 2003Kirner et al 2005;Wenzel et al 2009;Stattelmann and Martin 2010).…”

Section: Related Workmentioning

confidence: 99%

Calculating WCET estimates from timed traces

Zolda

Kirner

2015

Real-Time Syst

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Real-time systems engineers face a daunting duty: they must ensure that each task in their system can always meet its deadline. To analyse schedulability they must know the worst-case execution time (WCET) of each task. However, determining exact WCETs is practically infeasible in cost-constrained industrial settings involving real-life code and COTS hardware. Static analysis tools that could yield sufficiently tight WCET bounds are often unavailable. As a result, interest in portable analysis approaches like measurement-based timing analysis is growing. We present an approach based on integer linear programming (ILP) for calculating a WCET estimate from a given database of timed execution traces. Unlike previous work, our method specifically aims at reducing overestimation, by means of an automatic classification of code executions into scenarios with differing worst-case behaviour. To ease the integration into existing analysis tool chains, our method is based on the implicit path enumeration technique. It can thus reuse flow facts from other analysis tools and produces ILP problems that can be solved by off-the-shelf solvers.

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“…However, this approach has its merits when using scoped WCET calculation because the scoping allows to restrict the number of paths within each cluster such that their enumeration becomes feasible. For example, some path-oriented WCET calculation techniques use loop scopes as scopes for the analysis [18,58], which, however, implies that any flow information can address only program parts within the body of a single loop; the body of nested loops or the scope outside the loop cannot be mixed in.…”

Section: Epet (Path-oriented)mentioning

confidence: 99%

“…However, this approach has its merits when using scoped WCET calculation because the scoping allows to restrict the number of paths within each cluster such that their enumeration becomes feasible. For example, some path-oriented WCET calculation techniques use loop scopes as scopes for the analysis [18,58] Static WCET calculation based on EPET is well suited to analyze the effects of pipelines. It allows to model the impact of the pipeline on an instruction sequence longer than just basic blocks, and thus increases the precision of the WCET bound.…”

mentioning

confidence: 99%

Beyond loop bounds: comparing annotation languages for worst-case execution time analysis

et al. 2010

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Worst-case execution time (WCET) analysis is concerned with computing a precise-as-possible bound for the maximum time the execution of a program can take. This information is indispensable for developing safety-critical real-time systems, e. g., in the avionics and automotive fields. Starting with the initial works of Chen, Mok, Puschner, Shaw, and others in the mid and late 1980s, WCET analysis turned into a well-established and vibrant field of research and development in academia and industry. The increasing number and diversity of hardware and software platforms and the ongoing rapid technological advancement became drivers for the development of a wide array of distinct methods and tools for WCET analysis. The precision, generality, and efficiency of these methods and tools depend much on the expressiveness and usability of the annotation languages that are used to describe feasible and infeasible program paths. In this article we survey the annotation languages which we consider formative for the field. By investigating and comparing their individual strengths and limitations with respect to a set of pivotal criteria, we provide a coherent overview of the state of the art. Identifying open issues, we encourage further research. This way, our approach is orthogonal and complementary to a recent approach of Wilhelm et al. who provide a thorough survey of WCET analysis methods and tools that have been developed and used in academia and industry.Keywords Worst-case execution time (WCET) analysis · Annotation languages · Path-oriented, constraint-oriented, and hierarchy-oriented WCET annotation languages · WCET annotation language challenge MotivationComputing the time that the execution of a program can take in the worst case is challenging. It requires to cope with analysis problems that are computationally intractable or undecidable. Tools and methods for worst-case execution time analysis (WCET) thus usually content themselves to computing an upper bound of the actual WCET. The precision, generality, and efficiency of these tools and methods depend much on the accurate description and identification of feasible and infeasible program paths. A program path is feasible, 123 412 R. Kirner et al. if there is an actual program execution taking this path; it is infeasible otherwise. In practice, this information is computed by fully automatic program analyses, where possible; it is manually provided by application programmers otherwise. In both cases this requires a dedicated language in order to annotate this information and to pass it on to a subsequent WCET analysis. Such a language is commonly called an annotation language. Over the past two decades, an array of conceptually quite diverse annotation languages has been proposed to support the needs of different WCET analysis methods and tools.In this article, we present a systematic and comprehensive comparison of the various approaches for WCET annotation languages. This acts on our suggestion of the WCET annotation language challenge [32] comple...

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Complete worst-case execution time analysis of straight-line hard real-time programs

Cited by 89 publications

References 21 publications

The worst-case execution-time problem—overview of methods and survey of tools

The worst-case execution-time problem—overview of methods and survey of tools

Calculating WCET estimates from timed traces

Beyond loop bounds: comparing annotation languages for worst-case execution time analysis

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