X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/8f751cc565386f0b7bc5fce2fc3860e51a761c67..50d3f3d2e4566d454b32dbd5d26a14923fd33356:/docs/source/tuto_smpi.rst

diff --git a/docs/source/tuto_smpi.rst b/docs/source/tuto_smpi.rst
index 434a16152d..e0a693cfaf 100644
--- a/docs/source/tuto_smpi.rst
+++ b/docs/source/tuto_smpi.rst
@@ -3,6 +3,11 @@
 Simulating MPI Applications
 ===========================
 
+.. warning:: This document is still in early stage. You can try to
+   take this tutorial, but should not be surprised if things fall short.
+   It will be completed for the next release, v3.22, released by the end
+   of 2018.
+
 Discover SMPI
 -------------
 
@@ -49,7 +54,7 @@ To start using SMPI, you just need to compile your application with
 ``mpiff``, or with ``smpicxx`` instead of ``mpicxx``. Then, the only
 difference between the classical ``mpirun`` and the new ``smpirun`` is
 that it requires a new parameter ``-platform`` with a file describing
-the virtual platform on which your application shall run.
+the simulated platform on which your application shall run.
 
 Internally, all ranks of your application are executed as threads of a
 single unix process. That's not a problem if your application has
@@ -68,7 +73,7 @@ Describing Your Platform
 ------------------------
 
 As a SMPI user, you are supposed to provide a description of your
-virtual platform, that is mostly a set of simulated hosts and network
+simulated platform, that is mostly a set of simulated hosts and network
 links with some performance characteristics. SimGrid provides a plenty
 of :ref:`documentation <platform>` and examples (in the
 `examples/platforms <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms>`_
@@ -209,15 +214,28 @@ Dragonfly Cluster
 This topology was introduced to further reduce the amount of links
 while maintaining a high bandwidth for local communications. To model
 this in SimGrid, pass a ``topology="DRAGONFLY"`` attribute to your
-cluster.
+cluster. It's based on the implementation of the topology used on 
+Cray XC systems, described in paper
+`Cray Cascade: A scalable HPC system based on a Dragonfly network <https://dl.acm.org/citation.cfm?id=2389136>`_.
+
+System description follows the format ``topo_parameters=#groups;#chassis;#routers;#nodes``
+For example, ``3,4 ; 3,2 ; 3,1 ; 2``:
+
+- ``3,4``: There are 3 groups with 4 links between each (blue level).
+  Links to nth group are attached to the nth router of the group 
+  on our implementation.
+- ``3,2``: In each group, there are 3 chassis with 2 links between each nth router
+  of each group (black level)
+- ``3,1``: In each chassis, 3 routers are connected together with a single link
+  (green level)
+- ``2``: Each router has two nodes attached (single link) 
+
+.. image:: ../../examples/platforms/cluster_dragonfly.svg
+   :align: center
 
 .. literalinclude:: ../../examples/platforms/cluster_dragonfly.xml
    :language: xml
 
-.. todo::
-
-   Add the image, and the documuentation of the topo_parameters.
-
 Final Word
 ..........