Calling 2^31 times MPI_Iprobe results in the following error:
Abort(201962501) on node 0 (rank 0 in comm 0): Fatal error in PMPI_Iprobe: Invalid communicator, error stack:
PMPI_Iprobe(123): MPI_Iprobe(src=MPI_ANY_SOURCE, tag=MPI_ANY_TAG, MPI_COMM_WORLD, flag=0x7ffd925056c0, status=0x7ffd92505694) failed
PMPI_Iprobe(90).: Invalid communicator
On our system it takes about 10 Minutes to perform this number of calls in a loop.
The affected version is IntelMPI 2019.1.144 (based on MPICH 3.3)
The expected behavior is that MPI_Iprobe is neutral for the reference count of the provided communicator. Especially for MPI_COMM_WORLD, the reference count is superflous.