6. Validating your installation
6.1. Checking your Open MPI configuration
The ompi_info(1) 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(1) 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(1) 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: A- FRAMEWORKvalue of- alland a- COMPONENTvalue of- allwill 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_infoonly 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- --leveloption will display all MCA parameters from level 1 to- LEVEL(the max- LEVELvalue is 9). Use- ompi_info --param FRAMEWORK COMPONENT --level 9to see all MCA parameters for a given component. See “The Modular Component Architecture (MCA)” section, below, for a fuller explanation.
Changing the values of these MCA parameters is explained in the Tuning section.
6.2. 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(1) to launch a non-MPI program (e.g., - hostnameor- uptime) across multiple nodes.
- Use mpirun(1) to launch a trivial MPI program that does no MPI communication (e.g., the - hello_cprogram in the- examples/directory in the Open MPI distribution).
- Use mpirun(1) to launch a trivial MPI program that sends and receives a few MPI messages (e.g., the - ring_cprogram in the- examples/directory in the Open MPI distribution).
- Use oshrun(1) to launch a non-OpenSHMEM program across multiple nodes. 
- Use oshrun(1) to launch a trivial MPI program that does no OpenSHMEM communication (e.g., - hello_shmem.cprogram in the- examples/directory in the Open MPI distribution.)
- Use oshrun to launch a trivial OpenSHMEM program that puts and gets a few messages (e.g., the - ring_shmem.cin the- examples/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.