From: Arnaud Giersch Date: Sat, 9 May 2015 15:57:53 +0000 (+0200) Subject: Relecture SG. X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/rce2015.git/commitdiff_plain/e2082ae796c90fe550e1ad8e44f43f9d5bfedf95 Relecture SG. --- diff --git a/paper.tex b/paper.tex index eb8020a..17f27b3 100644 --- a/paper.tex +++ b/paper.tex @@ -88,7 +88,7 @@ Femto-ST Institute, DISC Department, University of Franche-Comté, Belfort, France. - Email:~\email{{charles.ramamonjisoa,david.laiymani,arnaud.giersch,raphael.couturier}@univ-fcomte.fr}\break + Email:~\email{{charles.ramamonjisoa,david.laiymani,raphael.couturier,arnaud.giersch}@univ-fcomte.fr}\break \affilnum{2} Department of Aerospace \& Mechanical Engineering, Non Linear Computational Mechanics, @@ -246,38 +246,38 @@ magnitude). To our knowledge, there is no study on this problematic. \label{sec:simgrid} In the scope of this paper, we have chosen the SimGrid -toolkit~\cite{SimGrid,casanova+giersch+legrand+al.2014.versatile} +toolkit~\cite{SimGrid,casanova+legrand+quinson.2008.simgrid,casanova+giersch+legrand+al.2014.versatile} to simulate the behavior of parallel iterative linear solvers on different computational grid configurations. In opposite to most of the simulators which -are stayed very oriented-application, the SimGrid framework is designed to study +are stayed very application-oriented, the SimGrid framework is designed to study the behavior of many large-scale distributed computing platforms as Grids, Peer-to-Peer systems, Clouds or High Performance Computation systems. It is still actively developed by the scientific community and distributed as an open source software. SimGrid provides four user interfaces which can be convenient for different -distributed applications~\cite{casanova+legrand+quinson.2008.simgrid}. In this -paper we are interested on the SMPI user interface (Simulator MPI) which -implements about \np[\%]{80} of the MPI 2.0 standard and allows minor -modifications of the initial code~\cite{bedaride+degomme+genaud+al.2013.toward} -(see Section~\ref{sec:04.02}). SMPI enables the direct simulation of the -execution, as in the real life, of an unmodified MPI distributed application, -and gets accurate results with the detailed resources consumption. - -SimGrid simulator uses at least three XML input files describing the -computational grid resources: the number of clusters in the grid, the number of -processors/cores in each cluster, the detailed description of the intra and -inter networks and the list of the hosts in each cluster (see the details in -Section~\ref{sec:expe}). SimGrid uses a fluid model to simulate the program -execution. It allows several simulation modes which produce accurate -results~\cite{bedaride+degomme+genaud+al.2013.toward,velho+schnorr+casanova+al.2013.validity}. For -instance, the "in vivo" mode really executes the computation but "intercepts" -the communications (the execution time is then evaluated according to the -parameters of the simulated platform). It is also possible for SimGrid/SMPI to -only keep the duration of large computations by skipping them. Moreover the -application can be run "in vitro" mode by sharing some in-memory structures -between the simulated processes and thus allowing the use of very large-scale -data. +distributed applications. In this paper we are interested on the SMPI +(Simulated MPI) user interface which implements about \np[\%]{80} of the MPI 2.0 +standard~\cite{bedaride+degomme+genaud+al.2013.toward}, and allows minor +modifications of the initial code (see Section~\ref{sec:04.02}). SMPI enables +the direct simulation of the execution, as in the real life, of an unmodified +MPI distributed application, and gets accurate results with the detailed +resources consumption. + +SimGrid simulator uses an XML input file describing the computational grid +resources: the number of clusters in the grid, the number of processors/cores in +each cluster, the detailed description of the intra and inter networks and the +list of the hosts in each cluster (see the details in +Section~\ref{sec:expe}). SimGrid employs a fluid model to simulate the use of +these resources along the program execution. This model produces accurate +results while still running relatively +fast~\cite{bedaride+degomme+genaud+al.2013.toward,velho+schnorr+casanova+al.2013.validity}. +During the simulation, the computation is really executed, but the commuications +are intercepted and their execution time evaluated according to the parameters +of the simulated platform. It is also possible for SimGrid/SMPI to only keep the +duration of large computations by skipping them. Moreover, when applicable, the +application can be run by sharing some in-memory structures between the +simulated processes and thus allowing the use of very large-scale data. The choice of SimGrid/SMPI as a simulator tool in this study has been emphasized by the results obtained by several studies to validate, in the real @@ -477,7 +477,7 @@ One of our objectives when simulating the application in SimGrid is, as in real life, to get accurate results (solutions of the problem) but also to ensure the test reproducibility under the same conditions. According to our experience, very few modifications are required to adapt a MPI program for the SimGrid -simulator using SMPI (Simulator MPI). The first modification is to include SMPI +simulator using SMPI (Simulated MPI). The first modification is to include SMPI libraries and related header files (\verb+smpi.h+). The second modification is to suppress all global variables by replacing them with local variables or using a SimGrid selector called "runtime automatic switching"