An efficient algorithm for parametric WCET calculation

Bygde, Stefan; Ermedahl, Andreas; Lisper, Björn

doi:10.1016/j.sysarc.2010.06.009

Cited by 29 publications

(35 citation statements)

References 7 publications

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“…Those assumptions guarantee that a WCET does actually exist and that an upper-bound to it is computable. Parametric static timing analyses have been proposed to soften the finiteness assumptions [20]: while they are useful to reuse results from static analysis, they only produce preliminary formulas that need instantiation before use. A real-time software program is therefore assumed to have a theoretical maximum execution time, the WCET, which needs to be estimated and upperbounded for safety.…”

Section: B Wcet Existence and Finitenessmentioning

confidence: 99%

On uses of extreme value theory fit for industrial-quality WCET analysis

Milutinović

Mezzetti

Abella

et al. 2017

2017 12th IEEE International Symposium on Industrial Embedded Systems (SIES)

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Abstract-Over the last few years, considerable interest has arisen in measurement-based probabilistic timing analysis. The term MBPTA has been used to indistinctly refer to a variety of different applications of Extreme Value Theory (EVT) to the timing analysis problem. The successful application of MBPTA techniques to a score of case studies has not fully dispelled the concerns that industrial stakeholders had with the quality of the computed bounds, hence ultimately with their industrial viability. Placing focus on the MBPTA methods and techniques developed in the PROARTIS and PROXIMA projects, collectively referred to as proMBPTA, we discuss the main misconceptions and pitfalls that can prevent a sound application of EVT-based WCET analysis. Using a combination of arguments and support examples, we show that proMBPTA is a rigorous process, fully amenable to sound and sustainable industrial use.

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Section: B Wcet Existence and Finitenessmentioning

confidence: 99%

On uses of extreme value theory fit for industrial-quality WCET analysis

Milutinović

Mezzetti

Abella

et al. 2017

2017 12th IEEE International Symposium on Industrial Embedded Systems (SIES)

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“…Unlike recent methods [15,5], we do not infer parametric bounds for programs. In fact, the outputs we produce are constant bounds and our method only successfully returns a bound for program on which the symbolic execution terminates.…”

Section: Our Contributions and Related Workmentioning

confidence: 99%

“…Implicit Path Enumeration Technique (IPET) [23] and its extensions (e.g. [11,13,5]) have been widely used due to its efficiency and simplicity. However, pure IPET methods have problems with infeasible paths and flow information stretching across loop-nesting levels.…”

Section: Other Related Workmentioning

confidence: 99%

Symbolic simulation on complicated loops for WCET path analysis

Chu

Jaffar

2011

Proceedings of the Ninth ACM International Conference on Embedded Software

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We address the Worst-Case Execution Time (WCET) Path Analysis problem for bounded programs, formalized as discovering a tight upper bound of a resource variable. A key challenge is posed by complicated loops whose iterations exhibit non-uniform behavior. We adopt a brute-force strategy by simply unrolling them, and show how to make this scalable while preserving accuracy.Our algorithm performs symbolic simulation of the program. It maintains accuracy because it preserves, at critical points, path-sensitivity. In other words, the simulation detects infeasible paths. Scalability, on the other hand, is dealt with by using summarizations, compact representations of the analyses of loop iterations. They are obtained by a judicious use of abstraction which preserves critical information flowing from one iteration to another. These summarizations can be compounded in order for the simulation to have linear complexity: the symbolic execution can in fact be asymptotically shorter than a concrete execution. Finally, we present a comprehensive experimental evaluation using a standard benchmark suite. We show that our algorithm is fast, and importantly, we often obtain not just accurate but exact results.

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“…Where the number of iterations may vary, the estimated number of iterations should be parametric in the program's variables rather than a simple numeric upper bound. This permits the deduction of tighter WCET estimates at the calculation stage and additionally permits parametric WCET to be undertaken [9], [10]. Furthermore, this allows for the number of loop executions in a procedure to be found as a function of the procedure's inputs, allowing tight estimates from multiple calling contexts.…”

Section: Model Inference For Loop Iteration Determinationmentioning

confidence: 99%

“…As the obtained estimates for the number of iterations are safe for this set, they can be used by existing static analysis techniques to yield safe overall WCETs. Indeed, as these formulae are parametric in program variables, they can be used in parametric WCET analysis [9], [10].…”

Section: Introductionmentioning

confidence: 99%

Accurate Determination of Loop Iterations for Worst-Case Execution Time Analysis

Bartlett

Bate

Kazakov

2010

IEEE Trans. Comput.

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Abstract-Determination of accurate estimates for the Worst-Case Execution Time of a program is essential for guaranteeing the correct temporal behaviour of any Real-Time System. Of particular importance is tightly bounding the number of iterations of loops in the program or excessive undue pessimism can result. This paper presents a novel approach to determining the number of iterations of a loop for such analysis. Program traces are collected and analysed allowing the number of loop executions to be parametrically determined safely and precisely under certain conditions. The approach is mathematically proven to be safe and its practicality is demonstrated on a series of benchmarks.

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An efficient algorithm for parametric WCET calculation

Cited by 29 publications

References 7 publications

On uses of extreme value theory fit for industrial-quality WCET analysis

On uses of extreme value theory fit for industrial-quality WCET analysis

Symbolic simulation on complicated loops for WCET path analysis

Accurate Determination of Loop Iterations for Worst-Case Execution Time Analysis

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