7. Validating your installation
7.1. Checking your Open MPI configuration
The ompi_info
command can be used to check the status of your Open
MPI installation (located in PREFIX/bin/ompi_info
). Running it with
no arguments provides a summary of information about your Open MPI
installation.
Note that the ompi_info
command is extremely helpful in determining
which components are installed as well as listing all the run-time
settable parameters that are available in each component (as well as
their default values).
The following ompi_info
options may be helpful:
--all
: Show a lot of information about your Open MPI installation.--parsable
: Display all the information in a machine-parsable format.--param FRAMEWORK COMPONENT
: AFRAMEWORK
value ofall
and aCOMPONENT
value ofall
will show all parameters to all components. Otherwise, the parameters of all the components in a specific framework, or just the parameters of a specific component can be displayed by using an appropriate FRAMEWORK and/or COMPONENT name.--level LEVEL
: By default,ompi_info
only shows “Level 1” MCA parameters – parameters that can affect whether MPI processes can run successfully or not (e.g., determining which network interfaces to use). The--level
option will display all MCA parameters from level 1 toLEVEL
(the maxLEVEL
value is 9). Useompi_info --param FRAMEWORK COMPONENT --level 9
to see all MCA parameters for a given component. See “The Modular Component Architecture (MCA)” section, below, for a fuller explanation.
Error
TODO move the ref below to a better / more-prominent place to explain how to set MCA params.
Changing the values of these parameters is explained in the Internal frameworks section.
7.2. Testing your Open MPI installation
When verifying a new Open MPI installation, we recommend running the following tests in order (the tests build upon each other):
Use
mpirun
to launch a non-MPI program (e.g.,hostname
oruptime
) across multiple nodes.Use
mpirun
to launch a trivial MPI program that does no MPI communication (e.g., thehello_c
program in theexamples/
directory in the Open MPI distribution).Use
mpirun
to launch a trivial MPI program that sends and receives a few MPI messages (e.g., thering_c
program in theexamples/
directory in the Open MPI distribution).Use
oshrun
to launch a non-OpenSHMEM program across multiple nodes.Use
oshrun
to launch a trivial MPI program that does no OpenSHMEM communication (e.g.,hello_shmem.c
program in theexamples/
directory in the Open MPI distribution.)Use
oshrun
to launch a trivial OpenSHMEM program that puts and gets a few messages (e.g., thering_shmem.c
in theexamples/
directory in the Open MPI distribution.)
If you can run all of these tests successfully, that is a good indication that Open MPI built and installed properly.