Intel® MPI Library

Developer Reference for Windows* OS

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ID 768734
Date 10/31/2024
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Document Table of Contents
Document Table of Contents x
Developer Reference for Windows* OS
Developer Reference for Windows* OS x
Introduction Command Reference Environment Variable Reference Notices and Disclaimers
Introduction x
Introducing Intel® MPI Library Notational Conventions Related Information User Authorization
Command Reference x
Compiler Commands mpiexec.hydra cpuinfo impi_info
Compiler Commands x
Compilation Command Options
mpiexec.hydra x
Global Hydra Options Local Hydra Options
Environment Variable Reference x
Compilation Environment Variables Hydra Environment Variables I_MPI_ADJUST Family Environment Variables Tuning Environment Variables I_MPI_TUNING_MODE I_MPI_TUNING_BIN I_MPI_TUNING_BIN_DUMP I_MPI_TUNING See Also Main Thread Pinning Environment Variables for Fabrics Control Environment Variables for Memory Policy Control Other Environment Variables
Tuning Environment Variables x
I_MPI_TUNING_MODE I_MPI_TUNING_BIN I_MPI_TUNING_BIN_DUMP I_MPI_TUNING See Also Autotuning
Autotuning x
I_MPI_TUNING_AUTO Family Environment Variables
Main Thread Pinning x
Environment Variables for Main Thread Pinning Interoperability with OpenMP* API
Environment Variables for Fabrics Control x
Communication Fabrics Control Shared Memory Control OFI*-capable Network Fabrics Control
Developer Reference for Windows* OS

Tuning Environment Variables

I_MPI_TUNING_MODE

Select the tuning method.

Syntax

I_MPI_TUNING_MODE=<arg>

Arguments

<arg > Description
none Disable tuning modes. This is the default value.
auto Enable autotuner.
auto:application Enable autotuner with application focused strategy (alias for auto).
auto:cluster Enable autotuner without application specific logic. This is typically performed with the help of benchmarks (for example, IMB-MPI1) and proxy applications.

Description

Set this environment variable to enable the autotuner functionality and set the autotuner strategy.

I_MPI_TUNING_BIN

Specify the path to tuning settings in a binary format.

Syntax

I_MPI_TUNING_BIN=<path>

Argument

<path > A path to a binary file with tuning settings. By default, Intel® MPI Library uses the binary tuning file located at <$I_MPI_ONEAPI_ROOT/etc>.

Description

Set this environment variable to load tuning settings in a binary format.

I_MPI_TUNING_BIN_DUMP

Specify the file for storing tuning settings in a binary format.

Syntax

I_MPI_TUNING_BIN_DUMP=<filename>

Argument

<filename> A file name of a binary that stores tuning settings. By default, the path is not specified.

Description

Set this environment variable to store tuning settings in binary format.

I_MPI_TUNING

Load tuning settings in a JSON format.

Syntax

I_MPI_TUNING=<path>

Argument

<path> A path to a JSON file with tuning settings.

Description

Set this environment variable to load tuning settings in a JSON format.

By default, the Intel® MPI Library loads tuning settings in a binary format. If it is not possible, the Intel MPI Library loads the tuning file in a JSON format specified through the I_MPI_TUNING environment variable. Thus, to enable JSON tuning, turn off the default binary tuning: I_MPI_TUNING_BIN="". If it is not possible to load tuning settings from a JSON file and in a binary format, the default tuning values are used.

You do not need to turn off binary or JSON tuning settings if you use I_MPI_ADJUST family environment variables. The algorithms specified with I_MPI_ADJUST environment variables always have priority over binary and JSON tuning settings.

Parent topic: Environment Variable Reference
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