Explorando memoria transacional em software nos contextos de arquiteturas assimetricas, jogos computacionais e consumo de energia / Exploiting software transactional memory in the context of asymmetric architectures


IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia




The shift towards multicore processors taken by the semiconductor industry has initiated an era in which new languages, methodologies and tools are of paramount importance to the development of efficient concurrent systems that can be built in a timely way by all kinds of programmers. One of the main obstacles faced by programmers when dealing with shared memory programming concerns the use of synchronization mechanisms so as to avoid race conditions that could possibly lead the system to an inconsistent state. Synchronization has been traditionally achieved by means of locks (or variations thereof), widely known by their anomalies and hard-to-get-it-right facets. A new mechanism, known as transactional memory (TM), has recently been the focus of a lot of research and shows potential to simplify code synchronization as well as delivering more parallelism and, therefore, better performance. This thesis presents three works focused on different aspects of software transactional memory (STM) systems. Firstly, we show an STM implementation for asymmetric processors, focusing on the architecture of Cell/B.E. As an important result, we find out that memory transactions are indeed promising for asymmetric architectures, specially due to their scalability. Secondly, we take a different approach to STM implementation by devising a system specially targeted at computer games. The decision was guided by poor performance figures usually seen on current STM implementations. We also conduct a case study using a complex game that effectively shows the system s efficiency. Finally, we present the energy consumption characterization of a state-of-the-art STM for the first time. Based on the observed characterization, we also propose a technique aimed at reducing energy consumption in highly contended scenarios. Our results show that the technique is indeed effective in such cases, improving the energy consumption by up to 87%


memoria transacional programação paralela (computação) arquitetura de computador estimativa de potencia transactional memory parallel programming (computer science) computer architecture power estimation

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