MPI Setup for Horovod 🔄

Setting up MPI (Message Passing Interface) is essential for distributed training with Horovod. Below are key steps to configure MPI on your system:

1. Install MPI Implementation

• OpenMPI:

  sudo apt-get install openmpi-bin openmpi-dev
  

  📌 Visit our guide for detailed installation steps
• MPICH:

  wget https://www.mpich.org/download/stable/v4.0.2/mpt-4.0.2.tar.gz
  tar -xzf mpt-4.0.2.tar.gz
  cd mpich-4.0.2
  ./configure --prefix=/usr/local
  make
  sudo make install
  

2. Verify MPI Installation

Run the following command to check if MPI is properly installed:

mpiexec --version

✅ Expected output: MPI: Open MPI 4.1.4 (or your installed version)

3. Configure Horovod with MPI

• Set environment variables:

  export HOROVOD_MPI_THREADS_NUM=2
  export HOROVOD_GPU_ALLREDUCE=nccl
  

• Install Horovod:

  pip install horovod
  

4. Run Distributed Training

Use mpiexec to launch training across multiple nodes:

mpiexec -n 4 python train_script.py

🧠 For more examples, check Horovod's distributed training tutorial.

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📌 *Figure: MPI setup architecture for multi-node training*