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C
Cunha, J. C., J. M. Lourenço, and T. Antão, "A Distributed Debugging Tool for a Parallel Software Engineering Environment", Proceedings of the 1st European Parallel Tools Meeting (EPTM'96), Paris, France, ONERA (French National Establishment for Aerospace Research), October, 1996. Abstracteptm96.pdf

We discuss issues in the design and implementation of a flexible debugging tool and its integration into a parallel software engineering environment.

Cunha, J. C., J. M. Lourenço, and V. Duarte, "The DDBG distributed debugger", Parallel Program Development for Cluster Computing, Commack, NY, USA, Nova Science Publishers, Inc., pp. 279–290, 2001. Abstractcap13.pdf

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Cunha, J. C., J. M. Lourenço, and T. Antão, "A Debugging Engine for a Parallel and Distributed Environment", Proceedings of the 1st Austrian-Hungarian Workshop on Distributed and Parallel Systems (DAPSYS'96), Wien, Austria, Hungarian Academy of Sciences, KFKI, pp. 111–118, 1996. Abstractdapsys96.pdf

This paper describes a debugging interface that has been developed for a parallel software engineering environment and that was developed on top of the PVM environment in the scope of the SEPP and HPCTI projects of the COPERNICUS Program. The main goal of this interface is to provide the basic debugging functionalities that are required by some components of that environment. We give special attention to the requirements posed by high-level tools of the environment, and to the need of providing a flexible debugging support layer that can be suitably adapted and extended. We present the system logical architecture and the interface specification of the debugging engine. We discuss its interfacing with other components of the environment, namely a graphical editor for the GRAPNEL visual parallel programming language, and a testing tool. We finally describe current work on the improvement of the debugging engine. Keywords: Debugging, monitoring, parallel processing, software tools.

Cunha, J. C., J. M. Lourenço, and V. Duarte, "Debugging of parallel and distributed programs", Parallel Program Development for Cluster Computing, Commack, NY, USA, Nova Science Publishers, Inc., pp. 97–129, 2001. Abstractcap03.pdf

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Cunha, J. C., P. D. Medeiros, J. M. Lourenço, V. Duarte, J. Vieira, B. Moscão, D. Pereira, and R. Vaz, "The DOTPAR Project: Towards a Framework Supporting Domain Oriented Tools for Parallel and Distributed Processing", Proceedings of the International Conference and Exhibition on High-Performance Computing and Networking (HPCN'98), London, UK, Springer-Verlag, pp. 952–954, 1998. Abstractdotpar98.pdf

We discuss the problem of building domain oriented environments by a composition of heterogeneous application components and tools. We describe several individual tools that support such environments, namely a distributed monitoring and control tool (DAMS), a process-based distributed debugger (PDBG) and a heterogeneous interconnection model (PHIS). We discuss our experience with the development of a Problem Oriented Environment in the domain of genetic algorithms, obtained by a composition of heterogeneous tools and application components.

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Dias, R. J., J. M. Lourenço, and G. Cunha, "Developing libraries using software transactional memory", Comput. Sci. Inf. Syst., vol. 5, issue 2, no. 2, pp. 103–117, 2008. Abstractcomsis_final.pdf

Software transactional memory is a promising programming model that adapts many concepts borrowed from the databases world to control concurrent accesses to main memory (RAM). This paper discusses how to support revertible operations, such as memory allocation and release, within software libraries that will be used in software memory transactional contexts. The proposal is based in the extension of the transaction life cycle state diagram with new states associated to the execution of user-defined handlers. The proposed approach is evaluated in terms of functionality and performance by way of a use case study and performance tests. Results demonstrate that the proposal and its current implementation are flexible, generic and efficient

Dias, R. J., J. Lourenço, and G. Cunha, "Developing Libraries Using Software Transactional Memory", CoRTA 2008: Proceedings of the Conference on Compilers, Related Technologies and Applications, Bragança, Portugal, Instituto Politécnico de Bragança - ESTG, 2008. Abstractcorta_2008.pdf

Software transactional memory (STM) is a promising programming model that adapts many concepts borrowed from the databases world to control concurrent accesses to main memory (RAM) locations. This paper aims at discussing how to support apparently irreversible operations within a memory transaction.

Dias, R. J., J. M. Lourenço, and J. C. Seco, Detection of Snapshot Isolation Anomalies in Software Transactional Memory: A Statical Analysis Approach, , no. UNL-DI-5-2011: Departamento de Informática FCT/UNL, 2011. Abstract

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Lourenço, J., D. Sousa, B. C. Teixeira, and R. J. Dias, "Detecting concurrency anomalies in transactional memory programs", Comput. Sci. Inf. Syst., vol. 8, issue 2, no. 2, pp. 533–548, 2011. Abstractcomsis-2011.pdf

Software transactional memory is a promising programming model that adapts many concepts borrowed from the databases world to control concurrent accesses to main memory (RAM). This paper discusses how to support revertible operations, such as memory allocation and release, within software libraries that will be used in software memory transactional contexts. The proposal is based in the extension of the transaction life cycle state diagram with new states associated to the execution of user-defined handlers. The proposed approach is evaluated in terms of functionality and performance by way of a use case study and performance tests. Results demonstrate that the proposal and its current implementation are flexible, generic and efficient

Lourenço, J. M., "A Debugging Engine for Parallel and Distributed Programs", Universidade Nova de Lisboa: Faculdade de Ciências e Tecnologia, 2004. Abstractfiddle-thesis.pdf

In the last decade a considerable amount of research work has focused on distributed debugging, one of the crucial fields in the parallel software development cycle. The productivity of the software development process strongly depends on the adequate definition of what debugging tools should be provided, and what debugging methodologies and functionalities should these tools support. The work described in this dissertation was initiated in 1995, in the context of two research projects, the SEPP (Software Engineering for Parallel Processing) and HPCTI (High-Performance Computing Tools for Industry), both sponsored by the European Union in the Copernicus program, which aimed at the design and implementation of an integrated parallel software development environment. In the context of these projects, two independent toolsets have been developed, the GRADE and EDPEPPS parallel software development environments. Our contribution to these projects was in the debugging support. We have designed a debugging engine and developed a prototype, which was integrated the both toolsets (it was the only tool developed in the context of the SEPP and HPCTI projects which achieved such a result). Even after the closing of those research projects, further research work on distributed debugger has been carried on, which conducted to the re-design and re-implementation of the debugging engine. This dissertation describes the debugging engine according to its most up-to-date design and implementation stages. It also reposts some of the experimental work made with both the initial and the current implementations, and how it contributed to validate the design and implementations of the debugging engine.

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Teixeira, B., J. M. Lourenço, E. Farchi, R. J. Dias, and D. Sousa, "Detection of Transactional Memory Anomalies using Static Analysis", Proceedings of the 8th Workshop on Parallel and Distributed Systems: Testing, Analysis, and Debugging (PADTAD'10), New York, NY, USA, ACM, pp. 26–36, 2010. Abstractpadatad-teixeira-2010.pdf

Transactional Memory allows programmers to reduce the number of synchronization errors introduced in concurrent programs, but does not ensures its complete elimination. This paper proposes a pattern matching based approach to the static detection of atomicity violation, based on a path-sensitive symbolic execution method to model four anomalies that may affect Transactional Memory programs. The proposed technique may be used to to bring to programmer's attention pairs of transactions that the programmer has mis-specified, and should have been combined into a single transaction. The algorithm first traverses the AST tree, removing all the non-transactional blocks and generating a trace tree in the path sensitive manner for each thread. The trace tree is a Trie like data structure, where each path from root to a leaf is a list of transactions. For each pair of threads, erroneous patterns involving two consecutive transactions are then checked in the trace tree. Results allow to conclude that the proposed technique, although triggering a moderate number of false positives, can be successfully applied to Java programs, correctly identifying the vast majority of the relevant erroneous patterns.