time is reported into the simulator.
.. image:: /tuto_smpi/img/big-picture.svg
- :align: center
+ :align: center
Describing Your Platform
------------------------
cluster. The route from ``node-0.simgrid.org`` to ``node-1.simgrid.org``
counts 3 links: the private link of ``node-0.simgrid.org``, the backbone
and the private link of ``node-1.simgrid.org``.
-
+
.. todo::
Add the picture.
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. It's based on the implementation of the topology used on
+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>`_.
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
+ 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)
+- ``2``: Each router has two nodes attached (single link)
.. image:: ../../examples/platforms/cluster_dragonfly.svg
:align: center
All needed dependencies are already installed in this container
(SimGrid, the C/C++/Fortran compilers, make, pajeng and R). Vite being
only optional in this tutorial, it is not installed to reduce the
-image size.
+image size.
The container also include the example platform files from the
previous section as well as the source code of the NAS Parallel
.. code-block:: shell
- git clone git@framagit.org:simgrid/simgrid-template-smpi.git
+ git clone https://framagit.org/simgrid/simgrid-template-smpi.git
cd simgrid-template-smpi/
If you struggle with the compilation, then you should double check
Compiling and Executing
.......................
-
+
Compiling the program is straightforward (double check your
:ref:`SimGrid installation <install>` if you get an error message):
.. code-block:: shell
-
+
$ smpicc -O3 roundtrip.c -o roundtrip
$ smpirun -np 16 -platform cluster_crossbar.xml -hostfile cluster_hostfile ./roundtrip
- The ``-np 16`` option, just like in regular MPI, specifies the
- number of MPI processes to use.
+ number of MPI processes to use.
- The ``-hostfile cluster_hostfile`` option, just like in regular
MPI, specifies the host file. If you omit this option, ``smpirun``
will deploy the application on the first machines of your platform.
- The ``-platform cluster_crossbar.xml`` option, **which doesn't exist
in regular MPI**, specifies the platform configuration to be
- simulated.
+ simulated.
- At the end of the line, one finds the executable name and
command-line arguments (if any -- roundtrip does not expect any arguments).
