I want to know how to use ltrace to get library function calls of mpi application but simply ltrace doesn't work and my mpirun cannot succeed. Any idea?
You should be able to simply use:
$ mpiexec -n 4 -other_mpiexec_options ltrace ./executable
But that will create a huge mess since the outputs from the different ranks will merge. A much better option is to redirect the output of ltrace to a separate file for each rank. Getting the rank is easy with some MPI implementations. For example, Open MPI exports the world rank in the environment variable OMPI_COMM_WORLD_RANK. The following wrapper script would help:
#!/bin/sh
ltrace --output trace.$OMPI_COMM_WORLD_RANK $*
Usage:
$ mpiexec -n 4 ... ltrace_wrapper ./executable
This will produce 4 trace files, one for each rank: trace.0, trace.1, trace.2, and trace.3.
For MPICH and other MPI implementations based on it and using the Hydra PM exports PMI_RANK and the above given script has to be modified and OMPI_COMM_WORLD_RANK replaced with PMI_RANK. One could also write an universal wrapper that works with both families of MPI implementations.