Tracking CSP computations

[EN] Tracing is one of the most important techniques for program understanding and debugging. A trace gives the user access to otherwise hidden information about a computation. In the context of concurrent languages, computations are particularly complex due to the non-deterministic execution order of processes and to the restrictions imposed on this order by synchronizations; hence, a tracer is a powerful tool to explore, understand and debug concurrent computations. In CSP, traces are sequences of events that define a particular execution. This notion of trace is completely different to the one used in other paradigms where traces are formed by those source code expressions evaluated during a particular execution. We refer to this second notion of traces as tracks. In this work, we introduce the theoretical basis for tracking concurrent and explicitly synchronized computations in process algebras such as CSP. Tracking computations in this kind of systems is a difficult task due to the subtleties of the underlying operational semantics which combines concurrency, non-determinism and non-termination. We define an instrumented operational semantics that generates as a side-effect an appropriate data structure (a track) which can be used to track computations. The formal definition of a tracking semantics improves the understanding of the tracking process, but also, it allows us to formally prove the correctness of the computed tracks. (C) 2018 Elsevier Inc. All rights reserved.This work has been partially supported by the EU (FEDER) and the Spanish Ministerio de Ciencia, Innovacion y Universidades/AEI under grant TIN2016-76843-C4-1-R and by the Generalitat Valenciana under grant PROMETEO-II/2015/013 (SmartLogic). The authors acknowledge a partial support of European COST Action IC1405 on Reversible Computation - extending horizons of computing. Salvador Tamarit was partially supported by the Conselleria de Educacion, Investigacion, Cultura y Deporte de la Generalitat Valenciana under the grant APOSTD/2016/036.Llorens Agost, ML.; Oliver Villarroya, J.; Silva, J.; Tamarit Muñoz, S. (2019). Tracking CSP computations. Journal of Logical and Algebraic Methods in Programming. 102:138-175. https://doi.org/10.1016/j.jlamp.2018.10.002S13817510

ReverCSP: Time-Travelling in CSP Computations

[EN] This paper presents reverCSP, a tool to animate both forward and backward CSP computations. This ability to reverse computations can be done step by step or backtracking to a given desired state of interest. reverCSP allows us to reverse computations exactly in the same order in which they happened, or also in a causally-consistent way. Therefore, reverCSP is a tool that can be especially useful to comprehend, analyze, and debug computations. reverCSP is an open-source project publicly available for the community. We describe the tool and its functionality, and we provide implementation details so that it can be reimplemented for other languages.This work has been partially supported by the EU (FEDER) and the Spanish MCI/AEI under grants TIN2016-76843-C4-1-R and PID2019- 104735RB-C41, and by the Generalitat Valenciana under grant Prometeo/2019/098 (DeepTrust).Galindo-Jiménez, CS.; Nishida, N.; Silva, J.; Tamarit, S. (2020). ReverCSP: Time-Travelling in CSP Computations. Springer. 239-245. https://doi.org/10.1007/978-3-030-52482-1_14S239245Bernadet, A., Lanese, I.: A modular formalization of reversibility for concurrent models and languages. In: Proceedings of ICE 2016, EPTCS (2016)Brown, G., Sabry, A.: Reversible communicating processes. Electron. Proc. Theor. Comput. Sci. 203, 45–59 (2016)Conserva Filhoa, M., Oliveira, M., Sampaio, A., Cavalcanti, A.: Compositional and local livelock analysis for CSP. Inf. Process. Lett 133, 21–25 (2018)Danos, V., Krivine, J.: Reversible communicating systems. In: Gardner, P., Yoshida, N. (eds.) CONCUR 2004. LNCS, vol. 3170, pp. 292–307. Springer, Heidelberg (2004). https://doi.org/10.1007/978-3-540-28644-8_19Elnozahy, E.N.M., Alvisi, L., Wang, Y.-M., Johnson, D.B.: A survey of rollback- recovery protocols in message-passing systems. ACM Comput. Surv. 34(3), 375–408 (2002)Fang, Y., Zhu, H., Zeyda, F., Fei, Y.: Modeling and analysis of the disruptor framework in csp. In: Proceedings of CCWC 2018. IEEE Computer Society (2018)Ladkin, P.B., Simons, B.B.: Static deadlock analysis for CSP-type communications. In: Fussell, D.S., Malek, M. (eds.) Responsive Computer Systems: Steps Toward Fault-Tolerant Real-Time Systems. The Springer International Series in Engineering and Computer Science, vol. 297, pp. 89–102. Springer, Boston (1995). https://doi.org/10.1007/978-1-4615-2271-3_5Landauer, R.: Irreversibility and heat generation in the computing process. IBM J. Res. Dev. 5, 183–191 (1961)Lanese, I., Antares Mezzina, C., Tiezzi, F.: Causal-consistent reversibility. Bull. EATCS 114, 17 (2014)Lanese, I., Nishida, N., Palacios, A., Vidal, G.: CauDEr: a causal-consistent reversible debugger for erlang. In: Gallagher, J.P., Sulzmann, M. (eds.) FLOPS 2018. LNCS, vol. 10818, pp. 247–263. Springer, Cham (2018). https://doi.org/10.1007/978-3-319-90686-7_16Lanese, I., Palacios, A., Vidal, G.: Causal-consistent replay debugging for message passing programs. In: Pérez, J.A., Yoshida, N. (eds.) FORTE 2019. LNCS, vol. 11535, pp. 167–184. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-21759-4_10Llorens, M., Oliver, J., Silva, J., Tamarit, S.: Dynamic slicing of concurrent specification languages. Parallel Comput. 53, 1–22 (2016)Llorens, M., Oliver, J., Silva, J., Tamarit, S.: Tracking CSP computations. J. Log. Algebr. Meth. Program. 102, 138–175 (2019)Perera, R., Garg, D., Cheney, J.: Causally consistent dynamic slicing. In Proceedings of CONCUR 2016, LIPIcs, vol. 59, pp. 18:1–18:15 (2016)Phillips, I., Ulidowski, I., Yuen, S.: A reversible process calculus and the modelling of the ERK signalling pathway. In: Glück, R., Yokoyama, T. (eds.) RC 2012. LNCS, vol. 7581, pp. 218–232. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-36315-3_18Roscoe, A.W.: The Theory and Practice of Concurrency. Prentice Hall PTR, Upper Saddle River (1997)Zhao, H., Zhu, H., Yucheng, F., Xiao, L.: Modeling and verifying storm using CSP. In: Proceedings of HASE 2019. IEEE Computer Society (2019

Analysis Techniques for Concurrent Programming Languages

Los lenguajes concurrentes est an cada d a m as presentes en nuestra sociedad, tanto en las nuevas tecnolog as como en los sistemas utilizados de manera cotidiana. M as a un, dada la actual distribuci on de los sistemas y su arquitectura interna, cabe esperar que este hecho siga siendo una realidad en los pr oximos a~nos. En este contexto, el desarrollo de herramientas de apoyo al desarrollo de programas concurrentes se vuelve esencial. Adem as, el comportamiento de los sistemas concurrentes es especialmente dif cil de analizar, por lo que cualquier herramienta que ayude en esta tarea, a un cuando sea limitada, ser a de gran utilidad. Por ejemplo, podemos encontrar herramientas para la depuraci on, an alisis, comprobaci on, optimizaci on, o simpli caci on de programas. Muchas de ellas son ampliamente utilizadas por los programadores hoy en d a. El prop osito de esta tesis es introducir, a trav es de diferentes lenguajes de programaci on concurrentes, t ecnicas de an alisis que puedan ayudar a mejorar la experiencia del desarrollo y publicaci on de software para modelos concurrentes. En esta tesis se introducen tanto an alisis est aticos (aproximando todas las posibles ejecuciones) como din amicos (considerando una ejecuci on en concreto). Los trabajos aqu propuestos di eren lo su ciente entre s para constituir ideas totalmente independientes, pero manteniendo un nexo com un: el hecho de ser un an alisis para un lenguaje concurrente. Todos los an alisis presentados han sido de nidos formalmente y se ha probado su correcci on, asegurando que los resultados obtenidos tendr an el grado de abilidad necesario en sistemas que lo requieran, como por ejemplo, en sistemas cr ticos. Adem as, se incluye la descripci on de las herramientas software que implementan las diferentes ideas propuestas. Esto le da al trabajo una utilidad m as all a del marco te orico, permitiendo poner en pr actica y probar con ejemplos reales los diferentes an alisis. Todas las ideas aqu presentadas constituyen, por s mismas, propuestas aplicables en multitud de contextos y problemas actuales. Adem as, individualmente sirven de punto de partida para otros an alisis derivados, as como para la adaptaci on a otros lenguajes de la misma familia. Esto le da un valor a~nadido a este trabajo, como bien atestiguan algunos trabajos posteriores que ya se est an bene ciando de los resultados obtenidos en esta tesis.Concurrent languages are increasingly present in our society, both in new technologies and in the systems used on a daily basis. Moreover, given the current systems distribution and their internal architecture, one can expect that this remains so in the coming years. In this context, the development of tools to support the implementation of concurrent programs becomes essential. Futhermore, the behavior of concurrent systems is particularly difficult to analyse, so that any tool that helps in this task, even if in a limited way, will be very useful. For example, one can find tools for debugging, analysis, testing, optimisation, or simplification of programs, which are widely used by programmers nowadays. The purpose of this thesis is to introduce, through various concurrent programming languages, some analysis techniques that can help to improve the experience of the software development and release for concurrent models. This thesis introduces both static (approximating all possible executions) and dynamic (considering a specific execution) analysis. The topics considered here differ enough from each other to be fully independent. Nevertheless, they have a common link: they can be used to analyse properties of a concurrent programming language. All the analyses presented here have been formally defined and their correctness have been proved, ensuring that the results will have the reliability degree which is needed for some systems (for instance, for critical systems). It also includes a description of the software tools that implement the different ideas proposed. This gives the work a usefulness well beyond the theoretical aspect, allowing us to put it in practice and to test the different analyses with real-world examples All the ideas here presented are, by themselves, approaches that can be applied in many current contexts and problems. Moreover, individually they serve as a starting point for other derived analysis, as well as for the adaptation to other languages of the same family. This gives an added value to this work, a fact confirmed by some later works that are already benefiting from the results obtained in this thesis.Tamarit Muñoz, S. (2013). Analysis Techniques for Concurrent Programming Languages [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31651TESI