Express Launch (DDT)

All of the Linaro Forge products can be launched by typing their name in front of an existing mpiexec command:

$ ddt mpiexec -n 128 examples/hello memcrash

This startup method is called Express Launch and is the simplest way to get started.

Note

Please add the Linaro Forge installation path to the PATH environment variable to make the Linaro DDT available to the console:

export PATH=<Forge installation path>/bin:$PATH

The MPI implementations supported by Express Launch are:

  • Bullx MPI

  • Cray X-Series (MPI/SHMEM/CAF)

  • Intel MPI

  • MPICH 3

  • MPICH 4

  • Open MPI (MPI/SHMEM)

  • Open MPI (Cray XT/XE/XK)

  • Cray XT/XE/XK (UPC)

  • SLURM (MPMD)

  • Cray PALS

If your MPI is not supported by Express Launch, an error message will display:

$ 'Generic' MPI programs cannot be started using Express Launch syntax (launching with an mpirun command).

Try this instead:
    ddt --np=256 ./wave_c 20

Type ddt --help for more information.

This is referred to as Compatibility Mode, in which the mpiexec command is not included and the arguments to mpiexec are passed via a --mpiargs="args here" parameter.

One advantage of Express Launch mode is that it is easy to modify existing queue submission scripts to run your program under one of the Linaro Forge products. This works best for Linaro DDT with Reverse Connect, ddt --connect, for interactive debugging or in offline mode (ddt --offline).

See Reverse Connect for more details.

If you cannot use Reverse Connect and want to use interactive debugging from a queue, you might need to configure Linaro DDT to generate job submission scripts for you. More details on this can be found in Start a job in a queue and in Integration with queuing systems.

Run dialog box

In Express Launch mode, the Run dialog has a restricted number of options:

Express Launch Run dialog box