PyTorch DDP on Sagemaker

Hi, I am using pytorch ddp on sagemaker. It is using mpi and running 4 separate processes on each of the 4 GPUs in g4dn.12xlarge. In pytorch, this is called ddp_sapwn, right? Is there a way to force DDP instead of ddp_spawn on Sagemaker? My distribution argument is

distribution = { 
    "pytorchddp": {
        "enabled": True,
        "custom_mpi_options": "-verbose -x NCCL_DEBUG=VERSION"
    }
}