484 research outputs found
Indefinite waitings in MIRELA systems
MIRELA is a high-level language and a rapid prototyping framework dedicated
to systems where virtual and digital objects coexist in the same environment
and interact in real time. Its semantics is given in the form of networks of
timed automata, which can be checked using symbolic methods. This paper shows
how to detect various kinds of indefinite waitings in the components of such
systems. The method is experimented using the PRISM model checker.Comment: In Proceedings ESSS 2015, arXiv:1506.0325
Timed automata for modelling caches and pipelines
In this paper, we focus on modelling the timing aspects of binary programs running on architectures featuring caches and pipelines. The objective is to obtain a timed automaton model to compute tight bounds for the worst-case execution time (WCET) of the programs using model-checking tehcniques.Author gratefully acknowledges the funding from projects TEC2011-28666-C04-02, TEC2014-58036-C4-3-R and grant BES-2012-055572, awarded by the Spanish Ministry of Economy and Competitivity
Comparison of Implicit Path Enumeration and Model Checking Based WCET Analysis
In this paper, we present our new worst-case execution time (WCET) analysis tool for Java processors, supporting both implicit path enumeration (IPET) and model checking based execution time estimation. Even though model checking is significantly more expensive than IPET, it simplifies accurate modeling of pipelines and caches. Experimental results using the UPPAAL model checker indicate that model checking is fast enough for typical tasks in embedded applications, though large loop bounds may lead to long analysis times. To obtain a tool which is able to cope with larger applications, we recommend to use model checking for more important code fragments, and combine it with the IPET approach
Exploring model-based development for the verification of real-time Java code
Many safety- and security-critical systems are real-time systems and, as a result, tools and techniques for verifying real-time systems are extremely important. Simulation and testing such systems can be exceedingly time-consuming and these techniques provide only probabilistic measures of correctness. There are a number of model-checking tools for real-time systems. However, they provide formal verification for models, not programs. To increase the confidence in real-time programs written in real-time Java, this paper takes a modelling approach to the design of such programs. First, models can be mechanically verified, to check whether they satisfy particular properties, by using current real-time model-checking tools. Then, programs are derived from the model by following a systematic approach. To illustrate the approach we use a nontrivial example: a gear controller
BEST: a Binary Executable Slicing Tool
We describe the implementation of BEST, a tool for slicing binary code. We aim to integrate this tool in a WCET estimation framework based on model checking. In this approach, program slicing is used to abstract the program model in order to reduce the state space of the system. In this article, we also report on the results of an evaluation of the efficiency of the abstraction technique
METAMOC: Modular Execution Time Analysis using Model Checking
Safe and tight worst-case execution times (WCETs) are important when scheduling hard real-time systems. This paper presents METAMOC, a path-based, modular method, based on model checking and static analysis, that determines safe and tight WCETs for programs running on platforms fea-turing caching and pipelining. The method works by constructing a UPPAAL model of the program being analysed and annotating the model with information from an inter-procedural value analysis. The program model is then combined with a model of the hardware platform, and model checked for the WCET. Through support for the platforms ARM7, ARM9 and ATMEL AVR 8-bit the modularity and retargetability of the method is demonstrated, as only the pipeline needs to be remodelled. Mod-elling the hardware is performed in a state-of-the-art graphical modeling environment. Experiments on the Mälardalen WCET benchmark programs show that taking caching into account yields much tighter WCETs, and that METAMOC is a fast and versatile approach for WCET analysis. 1
Tight WCRT Analysis for Synchronous C Programs
Accurate estimation of the tick length of a synchronous program is essential for efficient and predictable implementations that are devoid of timing faults. The techniques to determine the tick length statically are classified as worst case reaction time (WCRT) analysis. While a plethora of techniques exist for worst case execution time (WCET) analysis of procedural programs, there are only a handful of techniques for determining the WCRT value of synchronous programs. Most of these techniques produce overestimates and hence are unsuitable for the design of systems that are predictable while being also efficient. In this paper, we present an approach for the accurate estimation of the exact WCRT value of a synchronous program, called its tight WCRT value, using model checking. For our input specifications we have selected a synchronous C based language called PRET-C that is designed for programming Precision Timed (PRET) architectures. We then present an approach for static WCRT analysis of these programs via an intermediate format called TCCFG. This intermediate representation is then compiled to produce the input for the model checker. Experimental results that compare our approach to existing approaches demonstrate the benefits of the proposed approach. The proposed approach, while presented for PRET-C is also applicable for WCRT analysis of Esterel using simple adjustments to the generated model. The proposed approach thus paves the way for a generic approach for determining the tight WCRT value of synchronous programs at compile time
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