Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-10T12:35:43Z No. of bitstreams: 1 CarlosAvelinoDeBarros_TESE.pdf: 14220676 bytes, checksum: 5528aa72761d295e342d61cf12387c5e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-11T12:51:22Z (GMT) No. of bitstreams: 1 CarlosAvelinoDeBarros_TESE.pdf: 14220676 bytes, checksum: 5528aa72761d295e342d61cf12387c5e (MD5) / Made available in DSpace on 2017-01-11T12:51:22Z (GMT). No. of bitstreams: 1 CarlosAvelinoDeBarros_TESE.pdf: 14220676 bytes, checksum: 5528aa72761d295e342d61cf12387c5e (MD5) Previous issue date: 2016-07-13 / O per?odo que durou do surgimento dos microprocessadores at? o in?cio deste s?culo ficou marcado pela expans?o geom?trica da frequ?ncia de opera??o desses dispositivos. Se por um lado isso proporcionou aumentos cont?nuos do desempenho, tamb?m foi respons?vel por um crescimento problem?tico do aquecimento e do consumo de energia. No sentido de atenuar esses problemas, os processadores multi-core passaram a substituir extensivamente os processadores single-core, oferecendo uma alternativa vi?vel para aumentar o desempenho sem o aumento da frequ?ncia. Como uma das formas de se mapear o consumo de energia, apresentamos o desenvolvimento de dois conjuntos de modelos matem?ticos para a representa??o da pot?ncia el?trica dissipada nos processadores. De acordo com considera??es feitas em rela??o a suas parcelas est?tica e din?mica, estabelecemos a pot?ncia total como vari?vel dependente da frequ?ncia de opera??o dos respectivos processadores analisados. Demonstramos, a partir desses modelos matem?ticos, que o consumo relativo de energia dos processadores pode ser associado a medidas de desempenho empregadas em processamento paralelo, como speedup e efici?ncia. Tamb?m utilizamos os modelos para monitorar a influ?ncia de diversos fatores na redu??o do consumo de energia nos processadores multi-core, tais como o percentual da por??o paralela do c?digo, a quantidade de n?cleos a ser empregado de cada vez, a frequ?ncia de trabalho e o pr?prio speedup. Os resultados das an?lises, em simula??es e em hardware, confirmam as previs?es te?ricas e despertam a possibilidade de melhorar o desempenho energ?tico dos processadores multi-core, sobretudo nas condi??es em que os fatores de influ?ncia podem ser flexibilizados. / The period that lasted from the advent of microprocessors until early this century was marked by the geometric expansion of their operating frequency. If on one hand it provided continuous performance increases, on the other hand it was also responsible for a problematic growth in heating and energy consumption. In attempt to mitigate these problems, multi-core processors have been used extensively in replacement for singlecore processors, offering a viable alternative to increase performance without increasing frequency. As a way of mapping energy consumption, we present the development of two sets of mathematical models for the representation of the electrical power dissipated in the processors. According to considerations we made in relation to static and dynamic parts of the power, we established an equation for the total power as a function of the operating frequency of the respective analyzed processors. We demonstrate, based on these mathematical models, that the relative energy consumption of processors can be related to parallel processing performance measures, such as speedup and efficiency. We also use the models to monitor the influence of several factors on the reduction of energy consumption in multi-core processors, such as the percentage of the parallel portion of the code, the number of cores to be used each time, the working frequency and speedup itself. Results of the analyzes confirm the theoretical predictions and alert to the possibility of improving the energy performance of multi-core processors, especially in conditions in which the factors of influence can be made flexible.