DDT provides source-level debugging of Fortran, C, and C++ codes.

It can be used for debugging serial, multi-threaded (OpenMP), multi-process (MPI) and accelerator based (Cuda, OpenACC) programs running on production and research systems, including the CRAY Piz Daint system. It can be executed either as a graphical user interface (by using the DDT executable) or from the command-line (offline mode).

Using DDT

DDT is available on all CSCS Cray (and non Cray) systems. In order to check and use the debugger, type the following command:

module avail ddt

module load ddt

CSCS license enables DDT on all systems (up to >6000 compute nodes/gpus on PizDaint).
For source level debugging, the program must be compiled with the -g/-G (for nvcc) debugging flags.
You can then launch ddt directly from the login node or submit your debugging job via a slurm jobscript using the ddt --connect srun command.

Note that the -p debug partition can be used for debugging. If larger or longer debugging sessions are needed, please contact us.

Further information and troubleshooting


For more details, please have a look at:

In case of questions/remarks, please contact us at help(at)cscs.ch.