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


mpitune Utility


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


mpitune [options]


-a \"<app_cmd_line>\"

--application \"<app_cmd_line>\"

Collective Operations Control

Each collective operation in the Intel® MPI Library supports a number of communication algorithms. In addition to highly optimized default settings, the library provides a way to control the algorithm selection explicitly. You can do this by using the I_MPI_ADJUST environment variable family, which is described in the following section.

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