X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/31760320be7d37b9e87f60db1e1dc5407bf36be6..9372424b13ef7754541779ffa8096fe0e4b2d748:/docs/source/tuto_smpi.rst

diff --git a/docs/source/tuto_smpi.rst b/docs/source/tuto_smpi.rst
index 3b26c93eb3..bb16ec60e7 100644
--- a/docs/source/tuto_smpi.rst
+++ b/docs/source/tuto_smpi.rst
@@ -214,14 +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`` :
 
-.. literalinclude:: ../../examples/platforms/cluster_dragonfly.xml
-   :language: xml
+System description follows the format ``topo_parameters=#groups;#chassis;#routers;#nodes``
 
-.. todo::
+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) 
 
-   Add the image, and the documuentation of the topo_parameters.
+.. image:: ../../examples/platforms/cluster_dragonfly.svg
+   :align: center
+
+.. literalinclude:: ../../examples/platforms/cluster_dragonfly.xml
+   :language: xml
 
 Final Word
 ..........