Express Launch (DDT)
All of the Arm® 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 Arm® Forge installation path to the PATH environment variable to make the Arm® 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)
- Spectrum MPI
- Spectrum MPI (PMIx)
- Cray XT/XE/XK (UPC)
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
Arm® Forge products. This works best for Arm® 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 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.
