Tags: #mpi #scientific-computing
Environment variables can be inherited from the calling process (the default as of Intel MPI 2021.9.0), or specified via the -genv VARIABLE=value option to mpirun and mpiexec.
Debug information can be printed by setting the I_MPI_DEBUG variable, and the nodes selected are available at level 4:
$ mpirun -genv I_MPI_DEBUG=4 -n 1 ./mpi_application.x
Details about the environment variables are printed at level 5:
$ mpirun -genv I_MPI_DEBUG=5 -n 1 ./mpi_application.x
[0] MPI startup(): Intel(R) MPI Library, Version 2021.9 Build 20230307 (id: d82b3071db)
[0] MPI startup(): Copyright (C) 2003-2023 Intel Corporation. All rights reserved.
[0] MPI startup(): library kind: release
[0] MPI startup(): libfabric version: 1.13.2rc1-impi
[0] MPI startup(): libfabric provider: mlx
[0] MPI startup(): Load tuning file: "/p/app/compilers/intel/intel-hpckit/2023.1.0-46346/mpi/2021.9.0/etc/tuning_generic_shm-ofi_mlx_hcoll.dat"
[0] MPI startup(): Rank Pid Node name Pin cpu
[0] MPI startup(): 0 1980496 node_name {0}
[0] MPI startup(): I_MPI_ROOT=/p/app/compilers/intel/intel-hpckit/2023.1.0-46346/mpi/2021.9.0
[0] MPI startup(): I_MPI_MPIRUN=mpirun
[0] MPI startup(): I_MPI_HYDRA_TOPOLIB=hwloc
[0] MPI startup(): I_MPI_HYDRA_BOOTSTRAP=slurm
[0] MPI startup(): I_MPI_PIN_UNIT=-1
[0] MPI startup(): I_MPI_PIN=off
[0] MPI startup(): I_MPI_PIN_PROCESSOR_LIST=1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64
[0] MPI startup(): I_MPI_INTERNAL_MEM_POLICY=default
[0] MPI startup(): I_MPI_DEBUG=5