MPI 2.2 is already partially covered: over 160 primitives are
supported. Some parts of the standard are still missing: MPI-IO, MPI3
-collectives, spawning ranks, and some others. If one of the functions
-you use is still missing, please drop us an email. We may find the
-time to implement it for you.
+collectives, spawning ranks, inter-communicators, and some others. If
+one of the functions you use is still missing, please drop us an
+email. We may find the time to implement it for you.
Multi-threading support is very limited in SMPI. Only funneled
applications are supported: at most one thread per rank can issue any
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
..........
