This page summarizes known problems and troubleshoot information that help running experiments a a MHz rate.

1. Node configurations 

To achieve a MHz rate, we need to consider the following:

...

#!/bin/bash

#SBATCH --partition=anagpu
#SBATCH --nodes=2
#SBATCH --ntasks-per-node=3
#SBATCH --output=%j.log


# setup node configurations
./setup_nodes.sh


# "-u" flushes print statements which can otherwise be hidden if mpi hangs
# "-m mpi4py.run" allows mpi to exit if one rank has an exception
mpirun python -u -m mpi4py.run /reg/g/psdm/tutorials/examplePython/mpiDataSource.py

2. Open MPI failed to TCP connect

We observe that when running using more than a few nodes (> 20) and that nodes assigned to your job are from mixed pools (cmp, mon, or eb nodes mixed in), jobs may fail with the following message:

...

This happens because we have multiple interfaces (tcp, ib, etc.) assigned to a node, however some might not have all enabled and that results in no connection when a node is missing that selected interface.

Solution

Prior to running your job, apply either 1) or 2).

...