Intel® MPI Library Developer Guide for Linux* OS

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ID 768728
Date 3/22/2024
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Document Table of Contents
Document Table of Contents x
Intel® MPI Library Developer Guide for Linux* OS
Intel® MPI Library Developer Guide for Linux* OS x
Introduction Installation and Prerequisites Compiling and Linking Running Applications Debugging Applications Analysis and Tuning Troubleshooting Additional Supported Features Examples Notices and Disclaimers
Introduction x
Introducing Intel® MPI Library Conventions and Symbols Related Information
Installation and Prerequisites x
Installation Prerequisite Steps
Compiling and Linking x
Compiling an MPI Program Compilers Support ILP64 Support
Running Applications x
Running Intel® MPI Library in Containers Selecting a Library Configuration Running an MPI Program Running an MPI/OpenMP* Program See Also MPMD Launch Mode Fabrics Control Job Schedulers Support Controlling Process Placement Java* MPI Applications Support
Running Intel® MPI Library in Containers x
Build a Singularity* Container for an MPI Application Run the Application with a Container
Fabrics Control x
Selecting Fabrics Libfabric* Support OFI* Providers Support
Debugging Applications x
Debugging Using -gtool for Debugging
Analysis and Tuning x
Displaying MPI Debug Information Tracing Applications Interoperability with Other Tools Through -gtool MPI Tuning
Troubleshooting x
Error Message: Bad Termination Error Message: No such file or Directory Error Message: Permission Denied Error Message: Fatal Error Error Message: Bad File Descriptor Error Message: Too Many Open Files Problem: High Memory Consumption Readings Problem: MPI Application Hangs Problem: Password Required Problem: Cannot Execute Binary File Problem: MPI limitation for Docker*
Additional Supported Features x
Asynchronous Progress Control Multiple Endpoints Support
Multiple Endpoints Support x
MPI_THREAD_SPLIT Programming Model Threading Runtimes Support Program Examples Code Change Guide
Examples x
async_progress_sample.c thread_split.cpp thread_split_omp_for.c thread_split_omp_task.c thread_split_pthreads.c
Intel® MPI Library Developer Guide for Linux* OS

Running an MPI/OpenMP* Program

To run a hybrid MPI/OpenMP* program, follow these steps:

  1. Make sure the thread-safe (debug or release, as desired) Intel® MPI Library configuration is enabled (release is the default version). To switch to such a configuration, source vars.sh with the appropriate argument. See Selecting Library Configuration for details. For example: 
    $ source vars.sh release
  2. Set the I_MPI_PIN_DOMAIN environment variable to specify the desired process pinning scheme. The recommended value is omp: 
    $ export I_MPI_PIN_DOMAIN=omp

    This sets the process pinning domain size to be equal to OMP_NUM_THREADS. Therefore, if for example OMP_NUM_THREADS is equal to 4, each MPI process can create up to four threads within the corresponding domain (set of logical processors). If OMP_NUM_THREADS is not set, each node is treated as a separate domain, which allows as many threads per MPI process as there are cores.

    NOTE:
    For pinning OpenMP* threads within the domain, use the Intel® compiler KMP_AFFINITY environment variable. See the Intel compiler documentation for more details.
  3. Run your hybrid program as a regular MPI program. You can set the OMP_NUM_THREADS and I_MPI_PIN_DOMAIN variables directly in the launch command. For example: 
    $ mpirun -n 4 -genv OMP_NUM_THREADS=4 -genv I_MPI_PIN_DOMAIN=omp ./myprog

See Also

Intel® MPI Library Developer Reference, section Tuning Reference > Process Pinning > > Interoperability with OpenMP*.

Parent topic: Running Applications
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