@conference {inforum:2015:tvale, title = {Execu{\c c}{\~a}o concorrente e determinista de transa{\c c}{\~o}es}, booktitle = {Proceedings of INForum Simp{\'o}sio de Inform{\'a}tica}, series = {INForum 2015}, year = {2015}, note = {

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}, address = {Covilh{\~a}, Portugal}, abstract = {

Neste artigo apresentamos um protocolo de controlo de concorr{\^e}ncia que garante que a execu{\c c}{\~a}o concorrente de transa{\c c}{\~o}es {\'e} equivalente {\`a} sua execu{\c c}{\~a}o sequencial por uma ordem predefinida. Isto permite executar programas que usam transa{\c c}{\~o}es de forma determinista. O protocolo (1) permite, pela primeira vez, a execu{\c c}{\~a}o determinista de programas que usam mem{\'o}ria transacional por hardware; e (2) garante a execu{\c c}{\~a}o determinista de programas que usam mem{\'o}ria transacional por software com um desempenho claramente superior ao estado da arte.

}, keywords = {Fotografia digital, Processamento de imagem, Sistema de apoio {\`a} decis{\~a}o}, attachments = {https://docentes.fct.unl.pt/sites/default/files/joao-lourenco/files/inforum15-pot.pdf}, author = {Tiago Vale and Ricardo J. Dias and Silva, Jo{\~a}o A. and Jo{\~a}o M. Louren{\c c}o} } @article {CPE3098:2013:dias, title = {Efficient support for in-place metadata in Java software transactional memory}, journal = {Concurrency and Computation: Practice and Experience}, volume = {25}, number = {17}, year = {2013}, note = {

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}, pages = {2394{\textendash}2411}, abstract = {

Software transactional memory (STM) algorithms associate metadata with the memory locations accessed during a transaction{\textquoteright}s lifetime. This metadata may be stored in an external table by resorting to a mapping function that associates the address of a memory cell with the table entry containing the corresponding metadata (out-place or external strategy). Alternatively, the metadata may be stored adjacent to the associated memory cell by wrapping the cell and metadata together (in-place strategy). The implementation techniques to support these two approaches are very different and each STM framework is usually biased towards one of them, only allowing the efficient implementation of STM algorithms which suit one of the approaches and inhibiting a fair comparison with STM algorithms suiting the other. In this paper, we introduce a technique to implement in-place metadata that does not wrap memory cells, thus overcoming the bias and allowing STM algorithms to directly access the transactional metadata. The proposed technique is available as an extension to Deuce and enables the efficient implementation of a wide range of STM algorithms and their fair (unbiased) comparison in a common STM framework. We illustrate the benefits of our approach by analyzing its impact in two popular transactional memory algorithms with several transactional workloads, TL2 and multiversioning, each befitting out-place and in-place, respectively.

}, keywords = {bytecode instrumentation, data structures, Java, software transactional memory}, issn = {1532-0634}, doi = {10.1002/cpe.3098}, url = {http://dx.doi.org/10.1002/cpe.3098}, attachments = {https://docentes.fct.unl.pt/sites/default/files/joao-lourenco/files/ccpe2013-dias.pdf}, author = {Ricardo J. Dias and Vale, Tiago M. and Jo{\~a}o M. Louren{\c c}o} } @conference {europar-dias:2012, title = {Efficient Support for In-Place Metadata in Transactional Memory}, booktitle = {Proceedings of the 18th International Euro-Par Conference on Parallel Processing}, series = {{Euro-Par}}, year = {2012}, note = {

Distinguished paper award

}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {Berlin, Heidelberg}, abstract = {

Software Transactional Memory (STM) algorithms correctness rely on metadata associated with the memory locations accessed during the transaction life-time. STM implementations may store this metadata either in-place, by wrapping the memory cells in a container that includes the memory cell itself and the corresponding metadata, or out-place, by resorting to a mapping function that associates the memory cell address to an external table with the corresponding metadata. The implementation techniques for these two approaches are very different and each STM framework is usually biased towards one of them, only allowing the efficient implementation of algorithms that fall into the appropriate category, and inhibiting the fair comparison with STM algorithms falling into the other. In this paper we introduce a technique that supports the use of in-place metadata without requiring to wrap memory cells, thus providing STM algorithms with direct access to the transactional metadata and overcoming the bias. The proposed technique is available as an extension to the DeuceSTM framework and allows the efficient implementation of a wide range of STM algorithms, thus enabling their fair (unbiased) comparison in a common STM infrastructure. We illustrate the benefits of our approach by analyzing its impact in two popular TM algorithms with two different transactional workloads, TL2 and multi-versioning, which bias to out-place and in-place respectively.

}, url = {http://dx.doi.org/10.1007/978-3-642-32820-6_59}, attachments = {https://docentes.fct.unl.pt/sites/default/files/joao-lourenco/files/europar12.pdf}, author = {Ricardo J. Dias and Vale, Tiago M. and Jo{\~a}o M. Louren{\c c}o} } @conference {dias-hotpar-2011, title = {Efficient and Correct Transactional Memory Programs Combining Snapshot Isolation and Static Analysis}, booktitle = {Proceedings of the 3rd USENIX Conference on Hot Topics in Parallelism (HotPar{\textquoteright}11)}, series = {{HotPar}{\textquoteright}11}, year = {2011}, note = {

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}, month = {May}, publisher = {Usenix Association}, organization = {Usenix Association}, address = {Berkeley, USA}, abstract = {

Concurrent programs may suffer from concurrency anomalies that may lead to erroneous and unpredictable program behaviors. To ensure program correctness, these anomalies must be diagnosed and corrected. This paper addresses the detection of both low- and high-level anomalies in the Transactional Memory setting. We propose a static analysis procedure and a framework to address Transactional Memory anomalies. We start by dealing with the classic case of low-level dataraces, identifying concurrent accesses to shared memory cells that are not protected within the scope of a memory transaction. Then, we address the case of high-level dataraces, bringing the programmer{\textquoteright}s attention to pairs of memory transactions that were misspecified and should have been combined into a single transaction. Our framework was applied to a set of programs, collected form different sources, containing well known low- and high-level anomalies. The framework demonstrated to be accurate, confirming the effectiveness of using static analysis techniques to precisely identify concurrency anomalies in Transactional Memory programs.

}, attachments = {https://docentes.fct.unl.pt/sites/default/files/joao-lourenco/files/hotpar2011.pdf}, author = {Ricardo J. Dias and Jo{\~a}o M. Louren{\c c}o and Pregui{\c c}a, Nuno} } @article {Cunha:1999:ETI:315247.315257, title = {An experiment in tool integration: the {DDBG} parallel and distributed debugger}, journal = {J. Syst. Archit.}, volume = {45}, year = {1999}, note = {

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}, month = {may}, pages = {897{\textendash}907}, publisher = {Elsevier North-Holland, Inc.}, address = {New York, NY, USA}, abstract = {

Most known teaching experiences focus on parallel computing courses only, but some teaching experiences on distributed computing courses have also been reported. In this paper we describe a course on Parallel and Distributed Processing that is taught at undergraduate level in the Computer Science degree of our University.This course presents an integrated approach concerning concurrency, parallelism, and distribution issues. It{\textquoteright}s a breadth-first course addressing a wide spectrum of abstractions: the theoretical component focus on the fundamental abstractions to model concurrent systems, including process cooperation schemes, concurrent programming models, data and control distribution, concurrency control and recovery in transactional systems, and parallel processing models; the practical component illustrates the design and implementation issues involved in selected topics such as a data and control distribution problem, a distributed transaction-based support system and a parallel algorithm.We also discuss how this approach has been contributing to prepare the student to further actions regarding research and development of concurrent, distributed, or parallel systems.

}, keywords = {debugging, monitoring, parallel programming environments}, issn = {1383-7621}, doi = {10.1016/S1383-7621(98)00024-1}, url = {http://dx.doi.org/10.1016/S1383-7621(98)00024-1}, attachments = {https://docentes.fct.unl.pt/sites/default/files/joao-lourenco/files/jsa99.pdf}, author = {Cunha, Jos{\'e} C. and Jo{\~a}o M. Louren{\c c}o and Ant{\~a}o, Tiago} } @conference {DBLP:conf/pdpta/CunhaMDLG99, title = {An Experience in Building a Parallel and Distributed Problem-Solving Environment}, booktitle = {Proceedings of the International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA{\textquoteright}99)}, year = {1999}, note = {

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}, pages = {1804{\textendash}1809}, publisher = {CSREA Press}, organization = {CSREA Press}, abstract = {

We describe our experimentation with the design and implementation of specific environments, consisting of heterogeneous computational, visualization, and control components. We illustrate the approach with the design of a problem–solving environment supporting the execution of genetic algorithms. We describe a prototype supporting parallel execution, visualization, and steering. A life cycle for the development of applications based on genetic algorithms is proposed.

}, isbn = {1-892512-15-7}, attachments = {https://docentes.fct.unl.pt/sites/default/files/joao-lourenco/files/pdpta99.pdf}, author = {Cunha, Jos{\'e} C. and Medeiros, Pedro D. and Duarte, Vitor and Louren{\c c}o, Jo{\~a}o and Gomes, Cecilia} }