Set Up Environment to Offload DPC++, OpenMP* target, and OpenCL™ Applications to CPU

If you have an application that contains Data Parallel C++ (DPC++), C++/Fortran with OpenMP* target, or OpenCL™ code and prepared for offloading to a target device, you can analyze and model its potential performance on a different target device with the it with the Intel® Advisor.

To do this, use CPU offload profiling to offload your code temporarily to a CPU so that you can profile it and model its performance with the Offload Modeling perspective.

Important

Offload your DPC++, C++/Fortran with OpenMP target, or OpenCL code to CPU only to analyze it with the CPU-to-GPU Offload Modeling workflow. To analyze it with the GPU-to-GPU Offload Modeling workflow or GPU Roofline workflow, configure your system to analyze GPU kernels instead.

Depending on your operating system, do one of the following:

Linux* OS

For DPC++ code: Force offloading to a CPU using one of the following:
- Recommended: Set the SYCL_DEVICE_FILTER environment variable as follows:
```
export SYCL_DEVICE_FILTER=opencl:cpu
```
- If your application uses a SYCL device selector:
  1. In the application source code, add the following to specify the CPU as the target device:
```
sycl::cpu_selector
```
    For details, see Device selectors in the DPC++ Reference.
  2. Rebuild the application,
For OpenMP code: Force offloading to a CPU with one of the following:
- Recommended: To offload code to CPU, set the following environment variables:
```
export OMP_TARGET_OFFLOAD=MANDATORY
```
```
export LIBOMPTARGET_DEVICETYPE=CPU
```
```
export LIBOMPTARGET_PLUGIN=OPENCL
```
- To run code natively on CPU, set the following variable:
```
export OMP_TARGET_OFFLOAD=DISABLED
```
If your application uses OpenCL code: Configure your code to be offloaded to a CPU. Refer to the OpenCL documentation at https://www.khronos.org/registry/OpenCL/ for specific instructions.

Windows* OS

Set the following environment variable to use the JIT profiling API:
```
set INTEL_JIT_BACKWARD_COMPATIBILITY=1
```
For DPC++ code: Force offloading to a CPU using one of the following:
- Recommended: Set the SYCL_DEVICE_FILTER environment variable as follows:
```
set SYCL_DEVICE_FILTER=opencl:cpu
```
- If your application uses a SYCL device selector:
  1. In the application source code, add the following to specify the CPU as the target device:
```
sycl::cpu_selector
```
    For details, see Device selectors in the DPC++ Reference.
  2. Rebuild the application,
For OpenMP code: Force offloading to a CPU with one of the following:
- Recommended: To offload code to CPU, set the following environment variables:
```
set OMP_TARGET_OFFLOAD=MANDATORY
```
```
set LIBOMPTARGET_DEVICETYPE=CPU
```
```
set LIBOMPTARGET_PLUGIN=OPENCL
```
- To run code natively on CPU, set the following variable:
```
set OMP_TARGET_OFFLOAD=DISABLED
```
If your application uses OpenCL code: Configure your code to be offloaded to a CPU. Refer to the OpenCL documentation at https://www.khronos.org/registry/OpenCL/ for specific instructions.

Next Steps

Set up a project if you do not have one and run the Intel Advisorfrom a graphical user interface.
Run the Intel Advisorfrom a graphical user interface and set up a project if you do not have one.