Orientador: Hans Kurt Edmund Liesenberg / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-05T04:28:35Z (GMT). No. of bitstreams: 1 NevesJunior_Carlos_M.pdf: 1230174 bytes, checksum: d583db28ad2a79922429fb1cc37e40ca (MD5) Previous issue date: 2005 / Resumo: O objetivo do presente trabalho é o desenvolvimento do Gerente de Distribuição do ambiente de execução Xchart. O ambiente Xchart, tal como definido na tecnologia de mesmo nome, a Tecnologia Xchart, é composto por um conjunto de ferramentas que apóiam o desenvolvimento de gerenciadores de diálogo de interfaces de usuário. A especificação destes gerenciadores de diálogo é modular e com semântica prevendo a execução concorrente de seus componentes, o que permitiria a distribuição de tais componentes por uma rede de computadores. Xchart também dá nome à linguagem visual empregada na especificação e captura do controle de diálogo destas interfaces, e o fato de Xchart ser uma variante de Statecharts permite que a linguagem seja utilizada em um domínio maior, o domínio de sistemas reativos distribuídos. O Gerente de Distribuição é o componente do sistema de execução de Xchart que fornece os recursos para a execução concorrente e distribuída destes sistemas reativos. O atual trabalho implementa este componente e o sistema de execução de Xchart com tecnologias disponíveis na plataforma Java 2 Platform, Enterprise Edition (J2EE). J2EE é uma especificação de plataforma para desenvolvimento de aplicações corporativas distribuídas que oferece uma série de recursos tais como serviço de nomes e diretório, sistema de entrega de mensagens e mecanismos para controle de concorrência como gerenciamento de transações atômicas. O emprego de J2EE no desenvolvimento do ambiente Xchart visa reduzir o esforço de implementação destas funcionalidades típicas de sistemas distribuídos, além de aproveitar outros benefícios da linguagem JavaTM como a independência de plataforma / Abstract: The aim of the current project is the development of the Distribution Manager of the Xchart runtime environment. The Xchart environment as defined by the Xchart technology is composed by a set of tools that supports the development of dialogue managers of user interfaces. The specification of these dialogue managers is modular and describes the concurrent execution of these components, which allows a potential distribution of these components over a computer network. Xchart is also the name of the visual language used to specify and capture the dialogue control of user interfaces, and since Xchart is a variant of Statecharts, it can be applied in a major domain: the domain of the distributed reactive systems. The Distribution Manager is the component of this Xchart runtime system that provides the resources for concurrent and distributed execution of these reactive systems. The current project implements this component and the Xchart runtime system using available technologies of the Java 2 Platform, Enterprise Edition (J2EE). J2EE is a specification of platform for development of distributed enterprise applications that offers a set of resources like naming and directory services, message service and a concurrency control mechanism based on atomic transaction management. Some of the benefits on using J2EE technology for the development of the Xchart environment are the reduction of the efforts typically required by the implementation of regular distributed systems algorithms and also the platform independence model provided by Java / Mestrado / Sistemas de Computação / Mestre em Ciência da Computação

[pt] Ambientes de Execução Gerenciada tornaram-se alvos populares para compiladores de linguagens de programação de alto nível. Eles provêem um sistema tipos de alto nível com segurança de memória garantida, assim como facilidades como coleta de lixo, acesso a serviços da plataforma subjacente (possivelmente através de uma sandbox), multithreading, e uma rica biblioteca de estruturas de dados e algorithmos, mas não possuem um modelo de desempenho claro, o que atrapalha as tentativas de otimização de qualquer linguagem que não tenha um mapeamento direto na semântica do ambiente de execução, especialmente se a linguagem é dinamicamente tipada. Nós afirmamos que é possível construir um compilador para uma linguagem dinâmica que tem como alvo um ambiente de execução gerenciada que rivaliza um compilador que tem como alvo linguagem de máquina na eficiência do código que ele gera. Essa tese apresenta um compilador com tal característica, descrevendo as otimizações necessárias para sua construção, e testes de desempenho que validam essas otimizações. Nossas otimizações não dependem de geração de código em tempo de execução, apenas em informação estaticamente disponível no código fonte. Nós usamos uma nova análise de inferência de tipos para aumentar a quantidade de informação disponível. / [en] Managed runtime environments have become popular targets for compilers of high-level programming languages. They provide a high-level type system with enforced runtime safety, as well as facilities such as garbage collection, possibility sandboxed access to services of the underlying platform, multithreadng, and a rich library of data structures and algorithms. But managed runtime environments lack a clear performance model, which hinders attempts ar optimizing the compilation of any language that does nor have a direct mapping to the runtime environments semantics. This is aggravated if the language is dynamically typed. We assert that it is possible to build a compiler for a dynamic language that targets a managed runtime environment so that it rivals a compiler that targets machine code directly in efficiency of the code it generates. This dissertation presents such a compiler, describing the optimizations that were needed to build it, and benchmarks that validate these optimizations. Our optimizations do not depend on runtime code generation, only on information that is statically available from the source program. We use a novel type inference analysis to increase the amount of information available.

No description available.

Une pression accrue s'exerce sur les compilateurs pour mettre en œuvre des transformations de programmes de plus en plus complexes délivrant le potentiel de performance des processeurs multicœurs et des accélérateurs hétérogènes. L'espace de recherche des optimisations de programmes possibles est gigantesque est manque de structure. La recherche de la meilleure transformation, qui inclut la prédiction des gains estimés de performance offerts par cette transformation, constitue le problème le plus difficiles pour les compilateurs optimisants modernes. Nous avons choisi de nous concentrer sur les transformations de boucles et sur leur automatisation, exprimées dans le modèle polyédrique. Les méthodes d'optimisation de programmes dans le modèle polyédrique se répartissent grossièrement en deux classes. La première repose sur l'optimisation linéaire d'une fonction de analytique de coût. La deuxième classe de méthodes met en œuvre une recherche itérative. La première approche est rapide, mais elle est facilement mise en défaut en ce qui concerne la découverte de la solution optimale. L'approche itérative est plus précise, mais le temps de compilation peut devenir prohibitif. Cette thèse contribue une approche nouvelle de la recherche itérative de transformations de programmes dans le modèle polyédrique. La nouvelle méthode proposée possède la précision et la capacité effective à extraire des transformations profitables des méthodes itératives, tout en en minimisant les faiblesses. Notre approche repose sur l'évaluation systématique d'une fonction de coût et de prédiction de performances non-linéaire. Par ailleurs, la parallélisation automatique dans le modèle polyédrique est actuellement dominée par des outils de compilation source-à-source. Nous avons choisi au contraire d'implémenter nos techniques dans la plateforme GCC, en opérant sur une représentation de code de bas niveau, à trois adresses. Nous montrons que le niveau d'abstraction de la représentation intermédiaire choisie engendre des difficultés de passage à l'échelle, et nous montrons comment les surmonter. À l'inverse, nous montrons qu'une représentation intermédiaire de bas niveau ouvre de nouveaux degrés de liberté, bénéficiant à notre stratégie itérative de recherche de transformations, et à la compilation polyédrique de manière générale. / In order to take the performance advantages of the current multicore and heterogeneous architectures the compilers are required to perform more and more complex program transformations. The search space of the possible program optimizations is huge and unstructured. Selecting the best transformation and predicting the potential performance benefits of that transformation is the major problem in today's optimizing compilers. The promising approach to handling the program optimizations is to focus on the automatic loop optimizations expressed in the polyhedral model. The current approaches for optimizing programs in the polyhedral model broadly fall into two classes. The first class of the methods is based on the linear optimization of the analytical cost function. The second class is based on the exhaustive iterative search. While the first approach is fast, it can easily miss the optimal solution. The iterative approach is more precise, but its running time might be prohibitively expensive. In this thesis we present a novel search-based approach to program transformations in the polyhedral model. The new method combines the benefits - effectiveness and precision - of the current approaches, while it tries to minimize their drawbacks. Our approach is based on enumerating the evaluations of the precise, nonlinear performance predicting cost-function. The current practice is to use the polyhedral model in the context of source-to-source compilers. We have implemented our techniques in a GCC framework that is based on the low level three address code representation. We show that the chosen level of abstraction for the intermediate representation poses scalability challenges, and we show the ways to overcome those problems. On the other hand, it is shown that the low level IR abstraction opens new degrees of freedom that are beneficial for the search-based transformation strategies and for the polyhedral compilation in general.

La vérification déductive de programmes consiste à annoter des programmes par une spécification, c'est-à-dire un ensemble de formules logiques décrivant le comportement du programme, et à prouver que les programmes vérifient bien leur spécification. Des outils tels que la plate-forme Why prennent en entrée un programme et sa spécification et calculent des formules logiques telles que, si elles sont prouvées, le programme vérifie sa spécification. Ces formules logiques peuvent être prouvées automatiquement ou à l'aide d'assistants de preuve.Lorsqu'un programme est écrit dans un langage supportant les alias de pointeurs, c'est-à-dire si plusieurs variables peuvent désigner la même case mémoire, alors le raisonnement sur le programme devient particulièrement ardu. Il est nécessaire de spécifier quels pointeurs peuvent être égaux ou non. Les invariants des structures de données, en particulier, sont plus difficiles à vérifier.Cette thèse propose un système de type permettant de structurer la mémoire de façon modulaire afin de contrôler les alias de pointeurs et les invariants de données. Il est basé sur les notions de région et de permission. Les programmes sont ensuite interprétés vers Why de telle façon que les pointeurs soient séparés au mieux, facilitant ainsi le raisonnement. Cette thèse propose aussi un mécanisme d'inférence permettant d'alléger le travail d'annotation des opérations de régions introduites par le langage. Un modèle est introduit pour décrire la sémantique du langage et prouver sa sûreté. En particulier, il est prouvé que si le type d'un pointeur affirme que celui-ci vérifie son invariant, alors cet invariant est effectivement vérifié dans le modèle. Cette thèse a fait l'objet d'une implémentation sous la forme d'un outil nommé Capucine. Plusieurs exemples ont été écrits pour illustrer le langage, et ont été vérifié à l'aide de Capucine. / Deductive verification consists in annotating programs by a specification, i.e. logic formulas which describe the behavior of the program, and prove that programs verify their specification. Tools such as the Why platform take a program and its specification as input and compute logic formulas such that, if they are valid, the program verifies its specification. These logic formulas can be proven automatically or using proof assistants.When a program is written in a language supporting pointer aliasing, i.e. if several variables may denote the same memory cell, then reasoning about the program becomes particularly tricky. It is necessary to specify which pointers may or may not be equal. Invariants of data structures, in particular, are harder to maintain.This thesis proposes a type system which allows to structure the heap in a modular fashion in order to control pointer aliases and data invariants. It is based on the notions of region and permission. Programs are then translated to Why such that pointers are separated as best as possible, to facilitate reasoning. This thesis also proposes an inference mechanism to alleviate the need to write region operations introduced by the language. A model is introduced to describe the semantics of the language and prove its safety. In particular, it is proven that if the type of a pointer tells that its invariant holds, then this invariant indeed holds in the model. This work has been implemented as a tool named Capucine. Several examples have been written to illustrate the language, and where verified using Capucine.

Middleware technologies change so rapidly that designers must adapt existing software architectures to incorporate new emerging ones. This project proposes an architectural pattern and guidelines to abstract the communication barrier whereby allowing the developer to concentrate on the application logic. We demonstrate our approach and the feasibility of easily upgrading the middleware infrastructure by implementing a sample project and three case studies using three different middlewares on the .NET framework.

Orientador: Guido Costa Souza de Araújo / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-22T08:27:32Z (GMT). No. of bitstreams: 1 Nicacio_DanielHenricusdeKnegtDutra_D.pdf: 2579331 bytes, checksum: b8e15a6f91203b98455f39d63d63a634 (MD5) Previous issue date: 2012 / Resumo: Sistemas de Memória Transacional em Software (MTS) têm sido usados como uma abordagem para melhorar o desempenho ao permitir a execução concorrente de blocos atômicos. Porém, em cenários com alta contenção, sistemas baseados em MTS podem diminuir o desempenho consideravelmente, já que a taxa de conflitos aumenta. Políticas de gerenciamento de contenção têm sido usadas como uma forma de selecionar qual transação abortar quando um conflito ocorre. No geral, gerenciadores de contenção não são capazes de evitar conflitos, tendo em vista que eles apenas selecionam qual transação abortar e o momento em que ela deve reiniciar. Como gerenciadores de contenção agem somente após a detecção de um conflito, é difícil aumentar a taxa de transações finalizadas com sucesso. Abordagens mais pró-ativas foram propostas, focando na previsão de quando uma transação deve abortar e atrasando o início de sua execução. Contudo, as técnicas pró-ativas continuam sendo limitadas, já que elas não substituem a transação fadada a abortar por outra transação com melhores probabilidades de sucesso, ou quando o fazem, dependem do sistema operacional para essa tarefa, tendo pouco ou nenhum controle de qual transação será a substituta. Esta tese apresenta o LUTS, Lightweight User-Level Transaction Scheduler, um escalonador de transação de baixo custo em nível de usuário. Diferente de outras técnicas, LUTS provê maneiras de selecionar outra transação a ser executada em paralelo, melhorando o desempenho do sistema. Nós discutimos o projeto do LUTS e propomos uma heurística dinâmica, com o objetivo de evitar conflitos, que foi construída utilizando os métodos disponibilizados pelo LUTS. Resultados experimentais, conduzidos com os conjuntos de aplicações STAMP e STMBench7, e executando nas bibliotecas TinySTM e SwissTM, mostram como nossa heurística para evitar conflitos pode melhorar efetivamente o desempenho de sistema de MTS em aplicações com alta contenção / Abstract: Software Transaction Memory (STM) systems have been used as an approach to improve performance, by allowing the concurrent execution of atomic blocks. However, under high-contention workloads, STM-based systems can considerably degrade performance, as transaction conflict rate increases. Contention management policies have been used as a way to select which transaction to abort when a conflict occurs. In general, contention managers are not capable of avoiding conflicts, as they can only select which transaction to abort and the moment it should restart. Since contention manager's act only after a conflict is detected, it becomes harder to effectively increase transaction throughput. More proactive approaches have emerged, aiming at predicting when a transaction is likely to abort, postponing its execution. Nevertheless, most of the proposed proactive techniques are limited, as they do not replace the doomed transaction by another or, when they do, they rely on the operating system for that, having little or no control on which transaction to run. This article proposes LUTS, a Lightweight User-Level Transaction Scheduler. Unlike other techniques, LUTS provides the means for selecting another transaction to run in parallel, thus improving system throughput. We discuss LUTS design and propose a dynamic conflict-avoidance heuristic built around its scheduling capabilities. Experimental results, conducted with the STAMP and STMBench7 benchmark suites, running on TinySTM and SwissTM, show how our conflict-avoidance heuristic can effectively improve STM performance on high contention applications / Doutorado / Ciência da Computação / Doutor em Ciência da Computação

[pt] Gramáticas de Expressões de Parsing (PEGs) são um formalismo que permite descrever linguagens e que possui como característica distintiva o uso de um operador de escolha ordenada. A classe de linguagens descrita por PEGs contém propriamente todas as linguagens livres de contexto determinísticas. Nesta tese discutimos a correspondência de PEGs com dois outros formalismos usados para descrever linguagens: expressões regulares e Gramáticas Livres de Contexto (CFGs). Apresentamos uma formalização de expressões regulares usando semântica natural e mostramos uma transformação para converter expressões regulares em PEGs que descrevem a mesma linguagem; essa transformação pode ser facilmente adaptada para acomodar diversas extensões usadas por bibliotecas de expressões regulares (e.g., repetição preguiçosa e subpadrões independentes). Também apresentamos uma nova formalização de CFGs usando semântica natural e mostramos a correspondência entre CFGs lineares à direita e PEGs equivalentes. Além disso, mostramos que gramáticas LL(1) com uma pequena restrição descrevem a mesma linguagem quando interpretadas como CFGs e quando interpretadas como PEGs. Por fim, mostramos como transformar CFGs LL(k)-forte em PEGs equivalentes. / [en] Parsing Expression Grammars (PEGs) are a formalism that allow us to describe languages and that has as its distinguishing feature the use of an ordered choice operator. The class of languages described by PEGs properly contains all deterministic context-free languages. In this thesis we discuss the correspondence between PEGs and two other formalisms used to describe languages: regular expressions and Context-Free Grammars (CFGs). We present a new formalization of regular expressions that uses natural semantics and we show a transformation to convert a regular expression into a PEG that describes the same language; this transformation can be easily adapted to accommodate several extensions used by regular expression libraries (e.g., lazy repetition and independent subpatterns). We also present a new formalization of CFGs that uses natural semantics and we show the correspondence between right linear CFGs and equivalent PEGs. Moreover, we show that LL(1) grammars with a minor restriction define the same language when interpreted as a CFG and when interpreted as a PEG. Finally, we show how to transform strong-LL(k) CFGs into PEGs that are equivalent.

The interrelations of a set of software objects are usually manifold and complex. Common object-oriented programming languages provide constructs for structuring objects according to shared properties and behavior, but fail to provide abstraction mechanisms for the interactions of objects. Roles seem to be a promising approach to solve this problem as they focus on the behavior of an object in a certain context. Combining multiple roles yields collaborations, an interesting abstraction and reuse unit. However, existing approaches towards roles in programming languages require vast extensions of the underlying language or even propose new languages. We propose a programming technique that enables role-based programming with commonly available language constructs. Thus, programmers can express roles and collaborations by simply using a library, and hence, without the need to change the language, its compiler, and its tools. We explain our proposal on a language-independent level. Moreover, we provide an implementation in form of a library for the Scala programming language. Finally, we apply our ideas to design patterns and analyze to which extent these can be expressed and reused with roles. / Die Zusammenhänge zwischen Softwareobjekten sind vielfältig und komplex. In den meisten objektorientierten Programmiersprachen werden Objekte an Hand von gemeinsamen Eigenschaften und Verhalten klassifiziert. Konstrukte zum Strukturieren bezüglich ihrer Interaktionen fehlen jedoch. Ein vielversprechender Lösungsansatz sind Rollen, welche das Verhalten von Objekten in einem bestimmten Kontext beschreiben. Zusammenhängende Rollen können zu Kollaborationen abstrahiert werden. Diese sind insbesondere als wiederverwendbare Bausteine interessant. Allerdings verändern bisherige Ansätze zu rollenbasiertem Programmieren die zu Grunde liegende Sprache erheblich oder schlagen gar neue Sprachen vor. Im Gegensatz dazu zeigen wir eine Programmiermethode, die rollenbasiertes Programmieren mit üblichen Sprachkonstrukten ermöglicht. Somit können Rollen und Kollaborationen als Bibliothek bereitgestellt werden, also ohne Sprache, Compiler und Werkzeuge anpassen zu müssen. Wir erläutern unseren Ansatz zunächst sprachunabhängig. Desweiteren wird eine Implementierung als Bibliothek für die Scala Programmiersprache präsentiert. Als praktische Anwendung stellen wir Entwurfsmustern dar und überprüfen, inwiefern sich diese mit Rollen ausdrücken und wiederverwenden lassen.

Projektet undersökte olika verktyg och metoder som i skrivande stund används för att lära ut programmering. Den sammanfattar tidigare undersökningar och drar slutsatser kring hur lämpliga de är. Utifrån dessa slutsatser utformades en webbapplikation för undervisning.   Rapporten redogör för hur webbapplikationen konstruerades, samt vilka metoder och verktyg som användes i dess utveckling.   Detta ämne är högaktuellt idag då Sveriges regering ämnar införa programmering i grundskolan och då krävs både bra metoder och verktyg för detta. / This project investigated different tools and methods used today in teaching programming. It summarizes earlier studies and draws conclusions about how suited they are for the job. The accompanying web application would be crafted based on the conclusions made.   The report intends to describe how the web application was constructed, and which methods and tools were used during its development.   The subject of the report is highly relevant today since the Swedish government is discussing the introduction of programming classes in the elementary school. Thus demanding both suitable methods and tools.