View message queues

To open the Message Queues window, select Tools ‣ Message Queues. This will query the MPI processes for information about the state of the queues.

When the window is open, click Update to refresh the current queue information. Note that this will stop all playing processes. A dialog might be displayed while the data is being gathered. You can cancel the request at any time.

The message queue support library from your MPI implementation (if one exists) will be automatically loaded. If it fails to load, an error message will display.

Common reasons for failing to load include:

  • The support library does not exist, or its use must be explicitly enabled.

    Most MPIs will build the library by default, without additional configuration flags. MPICH 3 and MPICH 4 must be configured with the --enable-debuginfo argument. MVAPICH must be configured with the --enable-debug and --enable-sharedlib arguments. Some MPIs, notably Cray’s MPI, do not support message queue debugging at all.

    Intel MPI includes the library, but debug mode must be enabled. See Intel MPI for details.

    Open MPI automatically compile the library.

  • The support library is not available on the compute nodes where the MPI processes are running.

    Ensure the library is available, and set the environment variable FORGE_QUEUE_DLL if necessary to force using the library in its new location.

  • The support library has moved from its original installation location.

    Ensure the proper procedure for the MPI configuration is used. This might require you to specify the installation directory as a configuration option.

    Alternatively, you can specifically include the path to the support library in the LD_LIBRARY_PATH. If this is not convenient you can set the environment variable, FORGE_QUEUE_DLL, to the absolute path of the library itself (for example, /usr/local/mpich-3.3.0/lib/libtvmpich.so).

  • The MPI is built to a different bit-size to the debugger.

    In the unlikely case that the MPI is not built to the bit-size of the operating system, the debugger might not be able to find a support library that is the correct size. This is unsupported.