SupportMPI

SupportMPI provides MPI-based parallel processing classes for KVS.

Enable this support

Edit kvs.conf:

KVS_SUPPORT_MPI = 1

Or enable it when configuring with CMake:

cmake -S . -B build -DKVS_SUPPORT_MPI=ON

Requirements

SupportMPI requires an MPI implementation such as Open MPI, MPICH, Intel MPI, or Fujitsu MPI.

Install dependencies

Linux

Open MPI can be installed on Ubuntu as follows:

sudo apt-get install openmpi-bin libopenmpi-dev

MPICH can be installed as follows:

sudo apt-get install mpich libmpich-dev

macOS

brew install open-mpi

or:

brew install mpich

Windows

Use an MPI implementation compatible with your compiler environment.

MPI compiler variables

The make-based build uses MPI compiler wrapper variables when SupportMPI is enabled.

Variable	Default	Description
KVS_MPI_CPP	mpicxx	MPI C++ compiler wrapper
KVS_MPI_CC	mpicc	MPI C compiler wrapper
KVS_MPI_FC	mpif90	MPI Fortran compiler wrapper
KVS_MPI_LD	$(KVS_MPI_CPP)	MPI linker command

Example:

export KVS_MPI_CPP=mpiicpc

Manual path settings are also available:

export KVS_MPI_INCLUDE_PATH=/path/to/mpi/include
export KVS_MPI_LIBRARY_PATH=/path/to/mpi/lib
export KVS_MPI_LINK_LIBRARY="-lmpi"

Build KVS with make

export KVS_DIR=$HOME/local/kvs
export KVS_MPI_CPP=mpicxx
make
make install

If the MPI wrapper uses a different underlying C++ compiler from the compiler used to build KVS, set the wrapper-specific variable.

For Open MPI:

OMPI_CXX=clang++ kvsmake

For MPICH:

MPICH_CXX=clang++ kvsmake

Build KVS with CMake

cmake -S . -B build \
  -DKVS_DIR=$HOME/local/kvs \
  -DKVS_SUPPORT_MPI=ON \
  -DMPI_CXX_COMPILER=mpicxx
cmake --build build -j
cmake --install build

You can also use KVS_MPI_CPP:

KVS_MPI_CPP=mpicxx cmake -S . -B build -DKVS_SUPPORT_MPI=ON

Build examples

After installing KVS, generate an MPI-enabled Makefile with -use_mpi:

cd Example/SupportMPI/HelloWorld
kvsmake -G -use_mpi
kvsmake

Run the program with mpirun or the provided script:

mpirun -np 4 ./HelloWorld

or:

./run.sh

Example output:

Size = 4, Rank = 0
Size = 4, Rank = 1
Size = 4, Rank = 2
Size = 4, Rank = 3

HPC environment examples

# Fujitsu MPI
export KVS_MPI_CPP=mpiFCCpx

# Open MPI or MPICH
export KVS_MPI_CPP=mpicxx