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dc.contributorCortés, Toni
dc.contributor.authorFarreras Esclusa, Montse
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament d'Arquitectura de Computadors
dc.identifier.citationFarreras Esclusa, M. Optimizing programming models for massively parallel computers. Tesi doctoral, UPC, Departament d'Arquitectura de Computadors, 2008. ISBN 9788469460863.
dc.description.abstractSince the invention of the transistor, clock frequency increase was the primary method of improving computing performance. As the reach of Moore's law came to an end, however, technology driven performance gains became increasingly harder to achieve, and the research community was forced to come up with innovative system architectures. Today increasing parallelism is the primary method of improving performance: single processors are being replaced by multiprocessor systems and multicore architectures. The challenge faced by computer architects is to increase performance while limited by cost and power consumption. The appearance of cheap and fast interconnection networks has promoted designs based on distributed memory computing. Most modern massively parallel computers, as reflected by the Top 500 list, are clusters of workstations using commodity processors connected by high speed interconnects. Today's massively parallel systems consist of hundreds of thousands of processors. Software technology to program these large systems is still in its infancy. Optimizing communication has become a key to overall system performance. To cope with the increasing burden of communication, the following methods have been explored: (i) Scalability in the messaging system: The messaging system itself needs to scale up to the 100K processor range. (ii) Scalable algorithms reducing communication: As the machine grows in size the amount of communication also increases, and the resulting overhead negatively impacts performance. New programming models and algorithms allow programmers to better exploit locality and reduce communication. (iii) Speed up communication: reducing and hiding communication latency, and improving bandwidth. Following the three items described above, this thesis contributes to the improvement of the communication system (i) by proposing a scalable memory management of the communication system, that guarantees the correct reception of data and control-data, (ii) by proposing a language extension that allows programmers to better exploit data locality to reduce inter-node communication, and (iii) by presenting and evaluating a cache of remote addresses that aims to reduce control-data and exploit the RDMA native network capabilities, resulting in latency reduction and better overlap of communication and computation. Our contributions are analyzed in two different parallel programming models: Message Passing Interface (MPI) and Unified Parallel C (UPC). Many different programing models exist today, and the programmer usually needs to choose one or another depending on the problem and the machine architecture. MPI has been chosen because it is the de facto standard for parallel programming in distributed memory machines. UPC was considered because it constitutes a promising easy-to-use approach to parallelism. Since parallelism is everywhere, programmability is becoming important and languages such as UPC are gaining attention as a potential future of high performance computing. Concerning the communication system, the languages chosen are relevant because, while MPI offers two-sided communication, UPC relays on a one-sided communication model. This difference potentially influences the communication system requirements of the language. These requirements as well as our contributions are analyzed and discussed for both programming models and we state whether they apply to both programming models.
dc.format.extent223 p.
dc.publisherUniversitat Politècnica de Catalunya
dc.rightsADVERTIMENT. L'accés als continguts d'aquesta tesi doctoral i la seva utilització ha de respectar els drets de la persona autora. Pot ser utilitzada per a consulta o estudi personal, així com en activitats o materials d'investigació i docència en els termes establerts a l'art. 32 del Text Refós de la Llei de Propietat Intel·lectual (RDL 1/1996). Per altres utilitzacions es requereix l'autorització prèvia i expressa de la persona autora. En qualsevol cas, en la utilització dels seus continguts caldrà indicar de forma clara el nom i cognoms de la persona autora i el títol de la tesi doctoral. No s'autoritza la seva reproducció o altres formes d'explotació efectuades amb finalitats de lucre ni la seva comunicació pública des d'un lloc aliè al servei TDX. Tampoc s'autoritza la presentació del seu contingut en una finestra o marc aliè a TDX (framing). Aquesta reserva de drets afecta tant als continguts de la tesi com als seus resums i índexs.
dc.sourceTDX (Tesis Doctorals en Xarxa)
dc.subjectÀrees temàtiques de la UPC::Informàtica
dc.subject.otherModel de programació
dc.subject.otherAlt rendiment
dc.titleOptimizing programming models for massively parallel computers
dc.typeDoctoral thesis
dc.subject.lemacProgramari -- Optimització de recursos
dc.subject.lemacArquitectura d'ordinadors
dc.identifier.dlB. 27883-2011
dc.rights.accessOpen Access
dc.description.versionPostprint (published version)

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