gdb4hpc

gdb4hpc is used to debug parallel applications with multiple MPI ranks. Please do not forget to add -g as a compile flag to get the source code line information.

The debugger can be run as follows:

$ module load gdb4hpc
$ export CTI_SLURM_OVERRIDE_MC=1
$ gdb4hpc
dbg all> launch $a{8} --launcher-args="-N2" ./my_binary --args="arg1 arg2 arg3"
Starting application, please wait...
Launched application...
8/8 ranks connected... (timeout in 300 seconds)
8/8 ranks connected.
Created network...
Connected to application...
Launch complete.
a{0..7}: Initial breakpoint, main at /scratch/akbudak/iops/sw/hello.c:6
dbg all> bt
a{0..7}: #0  main at /scratch/akbudak/iops/sw/hello.c:6

Here, $a{8} means that 8 MPI tasks will launch. -N2 means that these MPI tasks will run on two nodes.