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Compilation Environment Variables
Hydra Environment Variables
I_MPI_ADJUST Family Environment Variables
Tuning Environment Variables
Process Pinning
GPU Support
I_MPI_OFFLOAD
I_MPI_OFFLOAD_MODE
I_MPI_OFFLOAD_SYMMETRIC
I_MPI_OFFLOAD_LEVEL_ZERO_LIBRARY
I_MPI_OFFLOAD_CUDA_LIBRARY
NIC Pinning
Environment Variables for Fabrics Control
Environment Variables for Memory Policy Control
Environment Variables for Asynchronous Progress Control
Environment Variables for Multi-EP
Other Environment Variables
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GPU Support
This section provides information about the following GPU devices support in Intel® MPI Library:
These features require the Level-Zero* library or CUDA* Library to be installed on the nodes. All environment variables have I_MPI_OFFLOAD_* prefix.
Current support is limited to Intel GPUs and Nvidia* GPUs only.
I_MPI_OFFLOAD
Set this environment variable to enable all GPU features.
Syntax
I_MPI_OFFLOAD=<value>
Arguments
| Value | Description |
|---|---|
| 0 | Disabled. This is the default value. |
| 1 | Enabled. |
Description
Set this environment variable to enable all GPU features such as GPU pinning and GPU buffers support, which give you ability to distribute devices between MPI ranks and provide a pointer of an offloaded memory to MPI functions.
I_MPI_OFFLOAD_MODE
Select the API for GPU/accelerator offloading.
Syntax
I_MPI_OFFLOAD_MODE=<value>
Arguments
| Value | Description |
|---|---|
| auto | Automatically identify GPU backend. This is the default value. |
| level_zero | Use Level-Zero API and library for GPU operations. |
| cuda | Use CUDA Driver API and library for GPU operations. |
Description
Set this environment variable to select the API for GPU/accelerator offloading.
I_MPI_OFFLOAD_SYMMETRIC
Enable/disable an assumption that all buffers in an operation have the same type.
Syntax
I_MPI_OFFLOAD_SYMMETRIC=<value>
Arguments
| Value | Description |
|---|---|
| 0 | Disabled. This is the default value. |
| 1 | Enabled. |
Description
Set this environment variable to enable/disable an assumption that all buffers in an operation have the same type. That is, buffers are allocated on GPU or HOST only.
Setting this variable optimizes device->device communications but disables handling of host->device and device->host cases.
I_MPI_OFFLOAD_LEVEL_ZERO_LIBRARY
Specify the name and full path to the Level-Zero library.
Syntax
I_MPI_OFFLOAD_LEVEL_ZERO_LIBRARY="<path>/<name>"
Arguments
| Argument | Description |
|---|---|
| <path> | Full path to the Level-Zero library. |
| <name> | Name of the Level-Zero library. |
Description
Set this environment variable to specify the name and full path to Level-Zero library. Set this variable if Level-Zero is not located in the default path. Default value: libze_loader.so.
I_MPI_OFFLOAD_CUDA_LIBRARY
Specify the name and full path to the CUDA Driver library.
Arguments
| Value | Description |
|---|---|
| <path> | Full path to the CUDA Driver library. |
| <name> | Name of the CUDA Driver library. |
Description
Set this environment variable to specify the name and full path to CUDA Driver library. Set this variable if CUDA is not located in the default path. The default value is ibcuda.so.See Also
Parent topic: Environment Variable Reference