\begin{abstract}
-
+\textcolor{blue}{
In recent years, green computing topic has being became an important topic in
the domain of the research. The increase in computing power of the computing
platforms is increased the energy consumption and the carbon dioxide emissions.
a CPU may increase the execution time of an application running on that
processor. Therefore, the frequency that gives the best trade-off between
the energy consumption and the performance of an application must be selected.
-
In this paper, a new online frequency selecting algorithm for heterogeneous
grid (heterogeneous CPUs) is presented. It selects the frequencies and tries to give the best
trade-off between energy saving and performance degradation, for each node
grid. The proposed algorithm is evaluated on real testbed, grid'5000 platform, while
running the NAS parallel benchmarks. The experiments show that it reduces the
energy consumption on average up to \np[\%]{30} while declines the performance
- on average by \np[\%]{3} only for the same instance. Finally, the algorithm is
+ on average by \np[\%]{3}. Finally, the algorithm is
compared to an existing method, the comparison results show that it outperforms the
- latter in term of energy and performance trade-off.
+ latter in term of energy and performance trade-off.}
\end{abstract}
The aim of this section is to evaluate the scaling algorithm while assuming different values of static powers.
In addition to the previously used percentage of static power, two new static power ratios, 10\% and 30\% of the measured dynamic power of the core, are used in this section.
The experiments have been executed with these two new static power scenarios over the one site one core per node scenario.
-In these experiments, the class D of the NAS parallel benchmarks are executed over Nancy's site. 16 computing nodes from the three clusters, Graphite, Graphene and Griffon, where used in this experiment.
+In these experiments, the class D of the NAS parallel benchmarks are executed over Nancy's site. 16 computing nodes from the three clusters, Graphite, Graphene and Griffon, where used in this experiment.
\begin{figure}
\centering
\label{fig:fre-pow}
\end{figure}
-
The energy saving percentages of the NAS benchmarks with the three static power scenarios are presented
in figure \ref{fig:eng_sen}. This figure shows that the 10\% of static power scenario
gives the biggest energy saving percentages in comparison to the 20\% and 30\% static power
is decreased for the other two scenarios because the scaling algorithm had selected different frequencies according to the static power values.
In the EP benchmark, the energy saving, performance degradation and tradeoff
-distance percentages for the these static power scenarios are not significantly different because there is no communication in this benchmark. Therefore, the static power is only consumed during computation and the proposed scaling algorithm selects similar frequencies for the three scenarios. On the other hand, for the rest of the benchmarks, the scaling algorithm selects the values of the frequencies according to the communication times of each benchmark because the static energy consumption increases proportionally to the communication times.
+distance percentages for the these static power scenarios are not significantly different because there is no communication in this benchmark. Therefore, the static power is only consumed during computation and the proposed scaling algorithm selects similar frequencies for the three scenarios. On the other hand, for the rest of the benchmarks, the scaling algorithm selects the values of the frequencies according to the communication times of each benchmark because the static energy consumption increases proportionally to the communication times.
-\subsection{The comparison between the proposed frequencies selecting algorithm and the energy and delay product algorithm}
+\subsection{The comparison of the proposed frequencies selecting algorithm }
\label{sec.compare_EDP}
Finding the frequencies that gives the best tradeoff between the energy consumption and the performance for a parallel
Both algorithms were applied to the class D of the NAS benchmarks over 16 nodes.
The participating computing nodes are distributed according to the two scenarios described in section \ref{sec.res}.
The experimental results, the energy saving, performance degradation and tradeoff distance percentages, are
-presented in the figures \ref{fig:edp-eng}, \ref{fig:edp-perf} and \ref{fig:edp-dist} respectively.
+presented in the figures \ref{fig:edp-eng}, \ref{fig:edp-perf} and \ref{fig:edp-dist} respectively.
+
+
\begin{figure}
\centering
\includegraphics[scale=0.5]{fig/edp_eng}
\caption{Comparing of the tradeoff distance for the proposed method with EDP method}
\label{fig:edp-dist}
\end{figure}
+
+
+
\textcolor{blue}{As shown form these figures, the proposed frequencies selection algorithm, Maxdist, outperform the EDP algorithm in term of energy and performance for all of the benchmarks executed over the two scenarios.
Generally, the proposed algorithm gives better results for all benchmarks because it is
optimized the distance between the energy saving and the performance degradation in the same time.
