DDT

Allinea DDT helps developers fix bugs quickly - from the desktop to the largest supercomputer. The most scalable parallel debugger for debugging MPI and multi-threaded codes, DDT leads the world in performance and usability.

Developer: Allinea Platforms: NEC Nehalem Cluster Category: Debugger License: Commercial Website: Allinea homepage

Usage

DDT is available through modules

module load debugger/ddt

Note: Do not forget to compile your application with debugging info (-g option)

Examples

starting the application from inside DDT

Set up the environment

module load debugger/ddt module load mpi/openmpi

Compile your application

mpicc -g your_app.c -o your_app

Start DDT:

ddt your_app

Select the right MPI Implementation in the Options and run your program.

Hermit special

On Hermit you can use DDT inside an interactive qsub session, but remember to add the -X flag to allow X-Server traffic:

qsub -I -X ....

module load ddt

ddt your_app

For MPI jobs, make sure that MPI is selected, the number of processes is correct, and that no queue is used.

Note: Ensure that you select "Cray XT/XE/XK (MPI/shmem)" as your MPI implementation and that the job is not submitted via the queuing system.

Nec Nehalem Cluster special

If you want to debug a parallel Program using Open MPI with DDT on the NEC Nehalem Cluster select 'OpenMPI (Compatibility)' as the desired MPI Implementation.

Cray XT5m special

If your program does IO take care to start an interactive session from the correct directory.

Hermit special

Currently the usage of DDT on Hermit is only supported within an interactive job.

qsub -IX [other job options]

To start your program under the control of DDT first load the ddt module

module load ddt ddt your_app

Note: Ensure that you select "Cray XT/XE/XK (MPI/shmem/UPC/CAF), no queue" as your MPI implementation such that the job is not submitted via the queuing system.

See also

• Software Development Tools, Compilers & Libraries

External links

• Allinea homepage
• DDT Demos
• DDT User Guide