+De: HPCC 2014 <hpcc2014@easychair.org>
+Objet: HPCC 2014 notification for paper 121
+Date: 26 juin 2014 15:24:40 UTC+2
+À: David Laiymani <david.laiymani@univ-fcomte.fr>
+
+Dear David Laiymani,
+
+On behalf of the Program Committee of HPCC 2014, we would like to
+inform you that the paper titled:Simulation of Asynchronous Iterative
+Algorithms Using SimGrid(paper ID number 121) has not been accepted
+for presentation at the main track of the conference but due to its
+quality, your paper is accepted in the associated Workshops of the
+HPCC2014 conference, and will be published in the same proceedings by
+IEEE CPS and indexed in IEEE Xplorer.
+
+Please modify your paper according to the instructions and comments
+provided by the reviewers.
+
+Please prepare and submit your final camera ready paper and follow all
+STEPs to ensure the submission process is completed
+successfully. Please note Camera ready submission deadline is 15 July
+2014.
+
+Authors must follow the IEEE formatting instruction.
+
+For further information please check:
+
+www.computational-science.org/HPCC2014
+
+We are looking forward to meeting you at the HPCC 2014 conference.
+
+S. Khaddaj, Program Chair of HPCC 2014
+J. Bourgeois, General Chair of HPCC2014
+F. Magoules, General Chair of HPCC2014
+
+
+----------------------- REVIEW 1 ---------------------
+PAPER: 121
+TITLE: Simulation of Asynchronous Iterative Algorithms Using SimGrid
+AUTHORS: Charles Emile Ramamonjisoa, David Laiymani, Arnaud Giersch,
+ Lilia Ziane Khodja and Raphaël Couturier
+
+
+----------- REVIEW -----------
+The contribution of the paper could be better described.
+
+The authors state that:
+
+"we show that SimGrid is an efficient simulation
+tool that has enabled .."
+
+If this is one of the goals of the paper to present the
+capabilities/strength of SimGrid, then they should compare it with
+other tools for the comparison of the two methods.
+
+Regarding the comparison of the two methods, the possible scalability
+expected in the case of larger platforms might also be commended /
+discussed.
+
+
+----------------------- REVIEW 2 ---------------------
+PAPER: 121
+TITLE: Simulation of Asynchronous Iterative Algorithms Using SimGrid
+AUTHORS: Charles Emile Ramamonjisoa, David Laiymani, Arnaud Giersch,
+ Lilia Ziane Khodja and Raphaël Couturier
+
+
+----------- REVIEW -----------
+This paper describes the simulation of an adapted (authors say
+slightly changed) GMRES solver on the SimGrid simulation framework;
+the GMRES solver is changed from synchronous iterative solution to a
+asynchronous iteration scheme in order to overcome latencies when
+interconnecting computers in a Grid environment.
+
+The prejudice of the paper is that the GMRES algorithm is not using
+non-blocking communication to begin with.
+
+
+You mention that for running with SimGrid using SMPI, "little" or no
+modification need to be done to the original code: what kind of
+modifications are necessary -- and did You have to apply any
+modification to run with SMPI? (in a later section of the paper,
+changing / deleting global variables were mentioned -- due to the
+threaded execution of simulated MPI processes...)
+
+
+SimGrid uses a "fluid model" -- what does that mean?
+
+The local convergence criterion (k<=MaxIter) seams wrong and should
+rather read: k == MaxIter?
+
+As far as the reviewer can tell, SMPI removes heavy computation by
+making assumptions on the CPU performance of the simulated code --
+which however is not true with most Grid environments where You do
+have mixed architectures and mixed performance characteristics. How
+is this handled?
+
+However, the main gripe about this paper is the rather unrealistic
+assumption on bandwidth (5 Mbps!) and latency (20ms): the internal
+network of a cluster may be Infiniband, with bw of Gigabytes/sec and
+micro-second latency, while a second cluster may be reachable over
+Gigabit-Ethernet with 100-200x the latency... This would be a setup,
+where a (even slight) gain would provide more convincing results.
+
+
+
+Some knitpicks include:
+- Abstract: "Behaviours", please no plural
+- Sec II (and others): "As exposed" --> "As described"
+- Sec II: "And important idle times" --> better "useless idle times
+ used for synchronization"
+- Sec III: "by the mean of an XML file" --> "by means of an XML file".
+- SEC IV.B: did not encouter ... unless some code debugging" -->
+ please rewrite the unless part...
+- SEC V: "Hosts processors power" --> "Host processor power"
+
+
+----------------------- REVIEW 3 ---------------------
+PAPER: 121
+TITLE: Simulation of Asynchronous Iterative Algorithms Using SimGrid
+AUTHORS: Charles Emile Ramamonjisoa, David Laiymani, Arnaud Giersch,
+ Lilia Ziane Khodja and Raphaël Couturier
+
+
+----------- REVIEW -----------
+The submitted paper purports to be the first simulation of
+asynchronous iterative algorithms and predicts that, for a particular
+cluster configurations with very high latency (20ms) and very low
+bandwidths (5/50 Mbit/s), an unpreconditioned asynchronous
+multisplitting algorithm will be faster than an unpreconditioned GMRES
+algorithm for solving a 3D Poisson equation.
+
+Several issues with respect to the relevance of these results deserve
+discussion:
+
+1) There is no substantial discussion of the fundamental additions to
+SimGrid that were required in order to support the simulation of
+asynchronous iterative algorithms. If no extensions were required,
+then I am unsure as to how this aspect of the work is a contribution.
+
+2) The model problem of a 3D Poisson equation with no preconditioner
+is regrettable due to the large number of fast solvers available that
+have been available for many decades. For this reason, as is, the
+results are not relevant to the solution of PDEs. However, a similar
+computational structure appears within the context of gradient descent
+methods for the solution of convex optimization problems, and
+asynchronous algorithms are quite common. I would humbly suggest such
+a model problem in the future unless either a more challenging PDE is
+tackled or a non-trivial preconditioner is incorporated.
+
+3) This is somewhat of a minor point, but I did not see an explicit
+discussion of the link between a global relative residual norm,
+|| A x - b|| / || b ||, and the local convergence criterion used in
+the asynchronous algorithm, which tested for the infinity norm of the
+local computation. When "precision" is reported in Table I, is it
+referring to a consistent global convergence criterion? And, if so,
+what is it precisely referring to?
+
+4) Typical latencies within clusters are on the order of a
+microsecond, and the latency used to produce Table I is more than
+three orders of magnitude higher (20ms). It would be helpful if more
+justification was given for why such a high latency is
+relevant. Furthermore, the chosen bandwidths (5 Mbit/s and 50 Mbit/s)
+are closer to a non-commercial home internet connection than a
+commercial ethernet connection.
+
+Overall, I feel that a significant number of issues should be
+addressed before publication would be warranted.
+
+
+----------------------- REVIEW 4 ---------------------
+PAPER: 121
+TITLE: Simulation of Asynchronous Iterative Algorithms Using SimGrid
+AUTHORS: Charles Emile Ramamonjisoa, David Laiymani, Arnaud Giersch,
+ Lilia Ziane Khodja and Raphaël Couturier
+
+
+----------- REVIEW -----------
+This is a very interesting paper devoted to the implementation in a
+grid environment of some asynchronous algorithm. These algorithms are
+indeed very powerfull, and the more latency, the more efficient are
+these algorithms. A comparison of a synchronous GMRES and an
+asynchronous multi-splitting is presented. The obtained results are
+interesting and confirm the efficiency of these methods.
+
+
+----------------------- REVIEW 5 ---------------------
+PAPER: 121
+TITLE: Simulation of Asynchronous Iterative Algorithms Using SimGrid
+AUTHORS: Charles Emile Ramamonjisoa, David Laiymani, Arnaud Giersch,
+ Lilia Ziane Khodja and Raphaël Couturier
+
+
+----------- REVIEW -----------
+This paper is a mix between a short and a long paper, it presents
+preliminary works on simulation of asynchronous iterative algorithms
+using SimGrid. I recommend to accept it as a short paper.
+
+
