Intel® MPI Library

DDT* Debugger

You can debug MPI applications using the Allinea* DDT* debugger. Intel does not provide support for this debugger, you should obtain the support from Allinea*. According to the DDT documentation, DDT supports the Express Launch feature for the Intel® MPI Library. You can debug your application as follows:

$ ddt mpirun -n <# of processes> [<other mpirun arguments>] <executable>

If you have issues with the DDT debugger, refer to the DDT documentation for help.

Environment Problems

Environmental errors may happen when there are problems with the system environment, such as mandatory system services are not running, shared resources are unavailable and so on.

When you encounter environmental errors, check the environment. For example, verify the current state of important services.

Example 1

Symptom/Error Message

librdmacm: Warning: couldn't read ABI version.
librdmacm: Warning: assuming: 4
librdmacm: Fatal: unable to get RDMA device list

or:

Running an MPI Program

Before running an MPI program, place it to a shared location and make sure it is accessible from all cluster nodes. Alternatively, you can have a local copy of your program on all the nodes. In this case, make sure the paths to the program match.

Run the MPI program using the mpiexec command. The command line syntax is as follows:

> mpiexec -n <# of processes> -ppn <# of processes per node> -f <hostfile> myprog.exe

For example:

mpitune Utility

mpitune

Use the mpitune utility to find optimal settings for the Intel® MPI Library relevant to your cluster configuration or your application.

Syntax

mpitune [options]

Options

-a \"<app_cmd_line>\"

--application \"<app_cmd_line>\"

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