Intel® MPI Library Developer Reference for Windows* OS

ID 768734
Date 3/31/2023
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

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.

NOTE:
The tuning settings in the JSON format are produced by the mpitune utility.

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.