Resolution:
Resolved
Workaround Link:
Affected Software:
STAR-CCM+ encounters errors when running MPI jobs with Intel MPI or OpenMPI, displaying the following message:
ib_iface.c:1139 UCX ERROR Invalid active_speed on mlx5_0:1: 128
This issue occurs because the UCX library (v1.8) bundled with STAR-CCM+ only supports Mellanox InfiniBand EDR, while Mellanox InfiniBand NDR (Next Data Rate) is used on Cardinal. As a result, STAR-CCM+ fails to communicate correctly over the newer fabric.
Affected versions
18.18.06.006, 19.04.009 and possibly later versions
Workaround
The solution for STAR-CCM+ is to bypass the UCX library for MPI communication by configuring the environment variables appropriately:
For Intel MPI:
export -n I_MPI_HYDRA_BOOTSTRAP_EXEC_EXTRA_ARGS
export I_MPI_HYDRA_BOOTSTRAP=ssh
export FI_PROVIDER=verbs
Set these variables before executing the starccm+ command.
For OpenMPI, append the following parameters to the starccm+ batch command:
-mpiflags "--mca pml ^ucx --mca --mca btl_openib_allow_ib 1"
