X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/rce2015.git/blobdiff_plain/d82538505eacc4b261cdfde4170ad69f2956c048..9793696f84bb746d5af3969fb0bc9105f9cb3a99:/paper.tex diff --git a/paper.tex b/paper.tex index 1b7b9eb..fa447f6 100644 --- a/paper.tex +++ b/paper.tex @@ -625,9 +625,7 @@ speed inter-cluster network (N1) and also on a less performant network (N2). Figure~\ref{fig:02} shows that end users will reduce the execution time for both algorithms when using a grid architecture like 4x16 or 8x8: the reduction is about $2$. The results depict also that when the network speed drops down (variation of 12.5\%), the difference between the two Multisplitting algorithms execution times can reach more than 25\%. -%\RC{c'est pas clair : la différence entre quoi et quoi?} -%\DL{pas clair} -%\RCE{Modifie} + %\begin{wrapfigure}{l}{100mm} @@ -772,10 +770,16 @@ on the algorithms performance in varying the CPU power of the clusters nodes from $1$ to $19$ GFlops. The outputs depicted in Figure~\ref{fig:06} confirm the performance gain, around $95\%$ for both of the two methods, after adding more powerful CPU. +\ \\ +%\DL{il faut une conclusion sur ces tests : ils confirment les résultats déjà +%obtenus en grandeur réelle. Donc c'est une aide précieuse pour les dev. Pas +%besoin de déployer sur une archi réelle} -\DL{il faut une conclusion sur ces tests : ils confirment les résultats déjà -obtenus en grandeur réelle. Donc c'est une aide précieuse pour les dev. Pas -besoin de déployer sur une archi réelle} +To conclude these series of experiments, with SimGrid we have been able to make +many simulations with many parameters variations. Doing all these experiments +with a real platform is most of the time not possible. Moreover the behavior of +both GMRES and Krylov multisplitting methods is in accordance with larger real +executions on large scale supercomputer~\cite{couturier15}. \subsection{Comparing GMRES in native synchronous mode and the multisplitting algorithm in asynchronous mode} @@ -871,7 +875,29 @@ geographically distant clusters through the internet. \section{Conclusion} -CONCLUSION + +In this paper we have presented the simulation of the execution of three +different parallel solvers on some multi-core architectures. We have show that +the SimGrid toolkit is an interesting simulation tool that has allowed us to +determine which method to choose given a specified multi-core architecture. +Moreover the simulated results are in accordance (i.e. with the same order of +magnitude) with the works presented in~\cite{couturier15}. Simulated results +also confirm the efficiency of the asynchronous multisplitting +algorithm compared to the synchronous GMRES especially in case of +geographically distant clusters. + +These results are important since it is very time consuming to find optimal +configuration and deployment requirements for a given application on a given +multi-core architecture. Finding good resource allocations policies under +varying CPU power, network speeds and loads is very challenging and labor +intensive. This problematic is even more difficult for the asynchronous +scheme where a small parameter variation of the execution platform and of the +application data can lead to very different numbers of iterations to reach the +converge and so to very different execution times. + + +Our future works... + %\section*{Acknowledgment}