X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/mpi-energy.git/blobdiff_plain/22f42ac179e2dfe1d37b10bb9a421ae3e8eea73b..234240c13f33fdf3a3c9a5fd08de3ca3a51614b3:/paper.tex diff --git a/paper.tex b/paper.tex index 8c272cb..bcbfb5d 100644 --- a/paper.tex +++ b/paper.tex @@ -10,12 +10,16 @@ \usepackage{colortbl} \usepackage{amsmath} +\usepackage{url} +\DeclareUrlCommand\email{\urlstyle{same}} + \usepackage[autolanguage,np]{numprint} \renewcommand*\npunitcommand[1]{\text{#1}} \usepackage{xspace} \usepackage[textsize=footnotesize]{todonotes} \newcommand{\AG}[2][inline]{\todo[color=green!50,#1]{\sffamily\textbf{AG:} #2}\xspace} +\newcommand{\JC}[2][inline]{\todo[color=red!10,#1]{\sffamily\textbf{JC:} #2}\xspace} \begin{document} @@ -31,14 +35,15 @@ \IEEEauthorblockA{% FEMTO-ST Institute\\ University of Franche-Comté\\ - IUT de Belfort-Montb\'{e}liard, Rue Engel Gros, BP 27, 90016 Belfort, France\\ - Fax : (+33)~3~84~58~77~32\\ - Email: \{jean-claude.charr, raphael.couturier, ahmed.fanfakh, arnaud.giersch\}@univ-fcomte.fr + IUT de Belfort-Montbéliard, 19 avenue du Maréchal Juin, BP 527, 90016 Belfort cedex, France\\ + Fax : +33~3~84~58~77~32\\ + Email: \email{{jean-claude.charr,raphael.couturier,ahmed.fanfakh_badri_muslim,arnaud.giersch}@univ-fcomte.fr} } } \maketitle +\AG{Is the fax number correct? Shall we add a telephone number?} \begin{abstract} Dynamic Voltage Frequency Scaling (DVFS) can be applied to modern CPUs. This technique is usually used to reduce the energy consumed by a CPU while @@ -47,7 +52,7 @@ exponentially related to its frequency. Thus, decreasing the frequency reduces the power consumed by the CPU. However, it can also significantly affect the performance of the executed program if it is compute bound and a low CPU frequency is selected. The performance degradation ratio can even be higher than -the saved energy ratio. Therefore, the chosen scaling factor must give the best possible tradeoff +the saved energy ratio. Therefore, the chosen scaling factor must give the best possible trade-off between energy reduction and performance. In this paper we present an algorithm @@ -101,20 +106,20 @@ benchmarks (NPB v3.3) developed by NASA~\cite{44}. Our experiments are executed using the simulator SimGrid/SMPI v3.10~\cite{Casanova:2008:SGF:1397760.1398183} over an homogeneous distributed memory architecture. Furthermore, we compare the proposed algorithm with Rauber and Rünger methods~\cite{3}. -The comparison's results show that our algorithm gives better energy-time tradeoff. +The comparison's results show that our algorithm gives better energy-time trade-off. This paper is organized as follows: Section~\ref{sec.relwork} presents related works from other authors. Section~\ref{sec.exe} shows the execution of parallel tasks and sources of idle times. It resumes the energy model of homogeneous platform. Section~\ref{sec.mpip} evaluates the performance -of MPI program. Section~\ref{sec.compet} presents the energy-performance tradeoffs +of MPI program. Section~\ref{sec.compet} presents the energy-performance trade-offs objective function. Section~\ref{sec.optim} demonstrates the proposed energy-performance algorithm. Section~\ref{sec.expe} verifies the performance prediction model and presents the results of the proposed algorithm. Also, It shows the comparison results. Finally, we conclude in Section~\ref{sec.concl}. \section{Related works} \label{sec.relwork} -\AG{Consider introducing the models sec.~\ref{sec.exe} maybe before related works} +\AG{Consider introducing the models (sec.~\ref{sec.exe}) before related works} In this section, some heuristics to compute the scaling factor are presented and classified into two categories: offline and online methods. @@ -164,7 +169,7 @@ The primary contribution of this paper is presenting a new online scaling factor \section{Execution and energy of parallel tasks on homogeneous platform} \label{sec.exe} -%\AG{The whole subsection ``Parallel Tasks Execution on Homogeneous Platform'', can be deleted if we need space, we can just say we are interested in this paper in homogeneous clusters} +%\JC{The whole subsection ``Parallel Tasks Execution on Homogeneous Platform'', can be deleted if we need space, we can just say we are interested in this paper in homogeneous clusters} \subsection{Parallel tasks execution on homogeneous platform} A homogeneous cluster consists of identical nodes in terms of hardware and software. Each node has its own memory and at least one processor which can @@ -174,8 +179,8 @@ we consider execution of the synchronous tasks on distributed homogeneous platform. These tasks can exchange the data via synchronous message passing. \begin{figure*}[t] \centering - \subfloat[Sync. imbalanced communications]{\includegraphics[scale=0.67]{commtasks}\label{fig:h1}} - \subfloat[Sync. imbalanced computations]{\includegraphics[scale=0.67]{compt}\label{fig:h2}} + \subfloat[Sync. imbalanced communications]{\includegraphics[scale=0.67]{fig/commtasks}\label{fig:h1}} + \subfloat[Sync. imbalanced computations]{\includegraphics[scale=0.67]{fig/compt}\label{fig:h2}} \caption{Parallel tasks on homogeneous platform} \label{fig:homo} \end{figure*} @@ -264,7 +269,7 @@ EQ~(\ref{eq:energy}). The optimal scaling factor is computed by minimizing the d \left( 1 + \sum_{i=2}^{N} \frac{T_i^3}{T_1^3} \right) } \end{equation} -\AG{The following 2 sections can be merged easily} +\JC{The following 2 sections can be merged easily} \section{Performance evaluation of MPI programs} \label{sec.mpip} @@ -340,10 +345,10 @@ performance as follows: \begin{figure*} \centering \subfloat[Converted relation.]{% - \includegraphics[width=.4\textwidth]{file.eps}\label{fig:r1}}% + \includegraphics[width=.4\textwidth]{fig/file}\label{fig:r1}}% \qquad% \subfloat[Real relation.]{% - \includegraphics[width=.4\textwidth]{file3.eps}\label{fig:r2}} + \includegraphics[width=.4\textwidth]{fig/file3}\label{fig:r2}} \label{fig:rel} \caption{The energy and performance relation} \end{figure*} @@ -466,10 +471,10 @@ time values. These scaling factors are computed by dividing the maximum frequency by the new one see EQ~(\ref{eq:s}). \begin{figure*}[t] \centering - \includegraphics[width=.328\textwidth]{cg_per.eps}\hfill% - \includegraphics[width=.328\textwidth]{mg_pre.eps}\hfill% - % \includegraphics[width=.4\textwidth]{bt_pre.eps}\qquad% - \includegraphics[width=.328\textwidth]{lu_pre.eps}\hfill% + \includegraphics[width=.328\textwidth]{fig/cg_per}\hfill% + \includegraphics[width=.328\textwidth]{fig/mg_pre}\hfill% + % \includegraphics[width=.4\textwidth]{fig/bt_pre}\qquad% + \includegraphics[width=.328\textwidth]{fig/lu_pre}\hfill% \caption{Comparing predicted to real execution time} \label{fig:pred} \end{figure*} @@ -507,13 +512,13 @@ energy saving percent and the minimum performance degradation percent at the same time from all available scaling factors. \begin{figure*}[t] \centering - \includegraphics[width=.328\textwidth]{ep.eps}\hfill% - \includegraphics[width=.328\textwidth]{cg.eps}\hfill% - \includegraphics[width=.328\textwidth]{sp.eps} - \includegraphics[width=.328\textwidth]{lu.eps}\hfill% - \includegraphics[width=.328\textwidth]{bt.eps}\hfill% - \includegraphics[width=.328\textwidth]{ft.eps} - \caption{Optimal scaling factors for predicted energy and performance of NAS benchmarks} + \includegraphics[width=.328\textwidth]{fig/ep}\hfill% + \includegraphics[width=.328\textwidth]{fig/cg}\hfill% + \includegraphics[width=.328\textwidth]{fig/sp} + \includegraphics[width=.328\textwidth]{fig/lu}\hfill% + \includegraphics[width=.328\textwidth]{fig/bt}\hfill% + \includegraphics[width=.328\textwidth]{fig/ft} + \caption{Optimal scaling factors for the predicted energy and performance of NAS benchmarks} \label{fig:nas} \end{figure*} \begin{table}[htb] @@ -551,7 +556,9 @@ optimal level without considering the performance as in EQ~(\ref{eq:sopt}). We refer to this scenario as $R_{E}$. The second scenario is similar to the first except setting the slower task to the maximum frequency (when the scale $S=1$) to keep the performance from degradation as mush as possible. We refer to this -scenario as $R_{E-P}$. While we refer to our algorithm as EPSA. The comparison is made in tables~(\ref{table:compareA},\ref{table:compareB},\ref{table:compareC}). These +scenario as $R_{E-P}$. While we refer to our algorithm as EPSA. The comparison +is made in tables \ref{table:compareA}, \ref{table:compareB}, +and~\ref{table:compareC}. These tables show the results of our method and Rauber and Rünger scenarios for all the NAS benchmarks programs for classes A,B and C. \begin{table}[p] @@ -682,27 +689,28 @@ As shown in tables~\ref{table:compareA},~\ref{table:compareB} and~\ref{table:com Figure~(\ref{fig:compare}) shows the maximum distance between the energy saving percent and the performance degradation percent. -Negative values mean that one of the two objectives (energy or performance) have been degraded more than the other. The positive tradeoffs with the highest values lead to maximum energy savings +Negative values mean that one of the two objectives (energy or performance) have been degraded more than the other. The positive trade-offs with the highest values lead to maximum energy savings while keeping the performance degradation as low as possible. Our algorithm always -gives the highest positive energy to performance tradeoffs while Rauber and Rünger method -($R_{E-P}$) gives in some time negative tradeoffs such as in BT and +gives the highest positive energy to performance trade-offs while Rauber and Rünger method +($R_{E-P}$) gives in some time negative trade-offs such as in BT and EP. \begin{figure*}[t] \centering - \includegraphics[width=.328\textwidth]{compare_class_A.pdf} - \includegraphics[width=.328\textwidth]{compare_class_B.pdf} - \includegraphics[width=.328\textwidth]{compare_class_c.pdf} + \includegraphics[width=.328\textwidth]{fig/compare_class_A} + \includegraphics[width=.328\textwidth]{fig/compare_class_B} + \includegraphics[width=.328\textwidth]{fig/compare_class_C} \caption{Comparing our method to Rauber and Rünger methods} \label{fig:compare} \end{figure*} \section{Conclusion} \label{sec.concl} -In this paper, we have presented a new online scaling factor selection method that optimizes simultaneously the energy and performance of a distributed application running on an homogeneous cluster. It uses the computation and communication times measured at the first iteration to predict energy consumption and the performance of the parallel application at every available frequency. Then, it selects the scaling factor that gives the best tradeoff between energy reduction and performance which is the maximum distance between the energy and the inverted performance curves. To evaluate this method, we have applied it to the NAS benchmarks and it was compared to Rauber and Rünger methods while being executed on the simulator SimGrid. The results showed that our method, outperforms Rauber and Rünger methods in terms of energy-performance ratio. +In this paper, we have presented a new online scaling factor selection method that optimizes simultaneously the energy and performance of a distributed application running on an homogeneous cluster. It uses the computation and communication times measured at the first iteration to predict energy consumption and the performance of the parallel application at every available frequency. Then, it selects the scaling factor that gives the best trade-off between energy reduction and performance which is the maximum distance between the energy and the inverted performance curves. To evaluate this method, we have applied it to the NAS benchmarks and it was compared to Rauber and Rünger methods while being executed on the simulator SimGrid. The results showed that our method, outperforms Rauber and Rünger methods in terms of energy-performance ratio. In the near future, we would like to adapt this scaling factor selection method to heterogeneous platforms where each node has different characteristics. In particular, each CPU has different available frequencies, energy consumption and performance. It would be also interesting to develop a new energy model for asynchronous parallel iterative methods where the number of iterations is not known in advance and depends on the global convergence of the iterative system. \section*{Acknowledgment} +\AG{Jean-Claude, why did you remove the Mésocentre here?} As a PhD student, M. Ahmed Fanfakh, would like to thank the University of Babylon (Iraq) for supporting his work. @@ -724,4 +732,4 @@ Babylon (Iraq) for supporting his work. %%% End: % LocalWords: Fanfakh Charr FIXME Tianhe DVFS HPC NAS NPB SMPI Rauber's Rauber -% LocalWords: CMOS EQ EPSA Franche Comté Tflop Rünger +% LocalWords: CMOS EQ EPSA Franche Comté Tflop Rünger IUT Maréchal Juin cedex