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Previous issue date: 2013-11-25 / Solving Systems of Linear Equations is important in several domains. In many cases, it
is necessary to employ verified computing to achieve reliable results. With the support of High
Performance Computing (HPC), solve efficiently huge linear systems with Verified Computing has
become possible. Recently, HPC researchers have started to investigate solutions focused not only
in performance but also in energy efficiency as well. In this context, the main goal of this work is to
propose the use of DVFS (Dynamic Voltage and Frequency Scaling) technique to change the CPU
frequency during the execution of a solver that employs Verified Computing. Furthermore, this works
intends to present a case study aiming at verifying if the use of DVFS can provide a reduction on
energy consumption without perfomance and accuracy being compromised. Initially, a study about
the FastPILSS solver was carried out to evaluate its accuracy, performance and energy consumption
over several different input matrices. After that, we observed that the use of DVFS does not affect
accuracy. Analysing the results, no reduction in energy consumption using the powersave governor
was observed if compared to the energy consumption using the performance governor. This occurs
due to the significant increase in execution time. When the frequency was changed in isolated steps
of the solver algorithm, it was possible to reduce up to 3,29% the energy consumption for dense
matrices during the approximate inverse calculation. / A resolu??o de Sistemas de Equa??es Lineares Alg?bricas (SELAs) ? importante em diversos
dom?nios do conhecimento. Em muitos casos, o uso de Computa??o Verificada ? necess?rio para
garantir que os resultados sejam confi?veis. Com o aux?lio da Computa??o de Alto Desempenho, a
resolu??o mais eficiente de SELAs de grande porte com o uso da Computa??o Verificada tornou-se
poss?vel. Atualmente, a ?rea de Alto Desempenho tem buscado solu??es que considerem, al?m do
desempenho, a efici?ncia energ?tica. Nesse sentido, o objetivo do trabalho ? utilizar a t?cnica DVFS
(Dynamic Voltage and Frequency Scaling) para modificar a frequ?ncia do processador na execu??o
de um solver de SELAs de Alto Desempenho com verifica??o do resultado. Al?m disso, realizar
um estudo de caso que permita avaliar se o uso de DVFS reduz o consumo de energia, bem como
avaliar de que maneira o desempenho e a exatid?o podem ser comprometidos. Inicialmente, foi
realizado um estudo de caso sobre o solver FastPILSS, analisando exatid?o, desempenho e consumo
de energia. Depois disso, verificou-se que a utiliza??o de DVFS n?o afetou a exatid?o. Com a
an?lise dos resultados, observou-se que n?o houve redu??o do consumo de energia ao utilizar o
governador em powersave se comparado ao consumo de energia com o governador em performance.
Esse comportamento pode ser atribu?do ao significativo aumento no tempo de execu??o. Ao realizar
a altera??o de frequ?ncia em pontos isolados no algoritmo do solver, observou-se que tendo como
entrada matrizes do tipo densas durante a realiza??o do c?lculo da inversa aproximada, obt?m-se
redu??o de no m?ximo 3,29% no consumo de energia.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/6480 |
| Date | 25 November 2013 |
| Creators | Lara, Viviane Linck |
| Contributors | Fernandes, Luiz Gustavo Le?o, Kolberg, Mariana Luderitz |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Ci?ncia da Computa??o, PUCRS, Brasil, Faculdade de Inform?tica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 1974996533081274470, 600, 600, 600, -3008542510401149144, 3671711205811204509 |
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