Contributions à la performance du calcul scientifique et embarqué

Habilitation à diriger les recherches (HDR)Ce document résume mes résultats de recherche après vingt années d'activité, y compris les travaux en collaboration avec trois étudiants ayant soutenu leur thèse de doctorat~: Julien Zory, Youcef Bouchebaba et Mehdi Amini. Il fournit une vue générale des résultats organisés selon les principales motivations qui ont soutenu leur développement, à savoir la performance, l'élégance, les expériences et la diffusion des connaissances. Ces travaux couvrent l'analyse statique pour la compilation ou la détection de problèmes dans les programmes, la génération de communications avec des méthodes polyédriques, la génération de code pour des accélérateurs matériels, mais aussi des primitives cryptographiques et un algorithme distribué. Ce document ne donne cependant pas une présentation détaillée des résultats, pour laquelle nous orientons le lecteur vers les articles de journaux, de conférences ou de séminaires correspondants. Les quatre thèmes abordés sont~: la performance -- l'essentiel des travaux vise à optimiser les performances de codes sur diverses architectures, du super calculateur à mémoire distribuée, à la carte graphique (GPGPU), jusqu'au système embarqué spécialisé~; l'élégance -- est un objectif des phases de conception, de même que trouver si possible des solutions optimales, tout en devant rester pratiques~; les expériences -- la plupart des algorithmes présentés sont implémentés, en général dans des logiciels libres, par exemple intégrés à des gros projets comme le logiciel PIPS ou diffusés de manière indépendante, de manière à conduire des expériences qui montrent l'intérêt pratique des méthodes~; les connaissances -- une large part de de mon activité est dédiée à la transmission des connaissances, pour des étudiants, des professionnels ou même le grand public. Le document se conclut par un projet de recherche présenté sous la forme d'une discussion et d'un ensemble de sujets de stage ou de thèse

PBIW : an encoding technique based on instruction patterns

Orientador: Rodolfo Jardim de AzevedoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Trabalhos não muito recentes já mostravam que o aumento de velocidade nas memórias DRAM não acompanha o aumento de velocidade dos processadores. Mesmo assim, pesquisadores na área de arquitetura de computadores continuam buscando novas abordagens para aumentar o desempenho dos processadores. Dentro do objetivo de minimizar essa diferença de velocidade entre memória e processador, este trabalho apresenta um novo esquema de codificação baseado em instruções codificadas e padrões de instruções ¿ PBIW (Pattern Based Instruction Word). Uma instrução codificada não contém redundância de dados e é armazenada em uma I-cache. Os padrões de instrução, de forma diferente, são armazenados em uma nova cache, chamada Pattern cache (P-cache) e são utilizados pelo circuito decodificador na preparação da instrução que será repassada aos estágios de execução. Esta técnica se mostrou uma boa alternativa para estilos arquiteturais conhecidos como arquiteturas VLIW e EPIC. Foi realizado um estudo de caso da técnica PBIW sobre uma arquitetura de alto desempenho chamada de 2D-VLIW. O desempenho da técnica de codificação foi avaliado através de experimentos com programas dos benchmarks MediaBench, SPECint e SPECfp. Os experimentos estáticos avaliaram a eficiência da codificação PBIW no aspecto de redução de código. Nestes experimentos foram alcançadas reduções no tamanho dos programas de até 81% sobre programas codificados com a estratégia de codifica¸c¿ao 2D-VLIW e reduções de até 46% quando comparados á programas utilizando o modelo de codificação EPIC. Experimentos dinâmicos mostraram que a codificação PBIW também é capaz que gerar ganhos com relação ao tempo de execução dos programas. Quando comparada à codificação 2D-VLIW, o speedup alcançado foi de at'e 96% e quando comparada à EPIC, foi de até 69%Abstract: Past works has shown that the increase of DRAM memory speed is not the same of processor speed. Even though, computer architecture researchers keep searching for new approaches to enhance the processor performance. In order to minimize this difference between the processor and memory speed, this work presents a new encoding technique based on encoded instructions and instruction patterns - PBIW (Pattern Based Instruction Word). An encoded instruction contains no redundancy of data and it is stored into an I-cache. The instruction patterns, on the other hand, are stored into a new cache, named Pattern cache (P-cache) and are used by the decoder circuit to build the instruction to be executed in the execution stages. This technique has shown a suitable alternative to well-known architectural styles such as VLIW and EPIC architectures. A case study of this technique was carried out in a high performance architecture called 2D-VLIW. The performance of the encoding technique has been evaluated through trace-driven experiments with MediaBench, SPECint and SPECfp programs. The static experiments have evaluated the PBIW code reduction efficiency. In these experiments, PBIW encoding has achieved up to 81% code reduction over 2D-VLIW encoded programs and up to 46% code reduction over EPIC encoded programs. Dynamic experiments have shown that PBIW encoding can also improve the processor performance. When compared to 2D-VLIW encoding, the speedup was up to 96% while compared to EPIC, the speedup was up to 69%MestradoArquitetura de ComputadoresMestre em Ciência da Computaçã

Annual Report of the University, 2001-2002, Volumes 1-4

VITAL ACADEMIC CLIMATE* by Brian Foster, Provost/Vice President of Academic Affairs A great university engages students and faculty fully in important ideas and issues ... not just to learn about them, but to take them apart and put them back together, to debate, deconstruct, resist, reconstruct and build upon them. Engagement of this sort takes concentration and commitment, and it produces the kind of discipline and passion that leads to student and faculty success and satisfaction in their studies, research, performance, artistic activity and service. It is also the kind of activity that creates a solid, nurturing spirit of community. This is what we mean when we talk about a vital academic climate. We are striving for an environment that will enrich the social, cultural and intellectual lives of all who come in contact with the University. Many things interconnect to make this happen: curriculum, co-curricular activities, conferences, symposia, cultural events, community service, research and social activity. Our goal is to create the highest possible level of academic commitment and excitement at UNM. This is what characterizes a truly great university. *Strategic Direction 2 New Mexico native Andres C. Salazar, a Ph.D. in electrical engineering from Michigan State University, has been named the PNM Chair in Microsystems, Commercialization and Technology. Carrying the title of professor, the PNM Chair is a joint appointment between the School of Engineering and the Anderson Schools of Management. Spring 2002 graduate John Probasco was selected a 2002 Rhodes Scholar, the second UNM student to be so honored in the past four years. The biochemistry major from Alamogordo previously had been awarded the Goldwater Scholarship and the Truman Scholarship. Andres c. Salazar Biology student Sophie Peterson of Albuquerque was one of 30 students nationwide to receive a 2002-2003 Award of Excellence from Phi Kappa Phi, the oldest and largest national honor society. Regents\\u27 Professor of Communication and Journalism Everett M. Rogers was selected the University\\u27s 4 71h Annual Research Lecturer, the highest honor UNM bestows upon members of its faculty. John Probasco honored by Student Activities Director Debbie Morris. New Mexico resident, author and poet Simon}. Ortiz received an Honorary Doctorate of Letters at Spring Commencement ceremonies. Child advocate Angela Angie Vachio, founder and executive director of Peanut Butter and Jelly Family Services, Inc., was awarded an Honorary Doctorate of Humane Letters. American Studies Assistant Professor Amanda}. Cobb won the 22 d annual American Book Award for listening to Our Grandmothers\\u27 Stories: The Bloomfield Academy for Chickasaw Females, 1852-1949