CODEWITHSUNDEEP
c++windowsdllcudaopencl
Damian Nadales
Damian Nadales

Reputation: 5037

Use Intel OpenCL.dll alongside a NVIDA CUDA installation

I have a computer that has an Intel CPU and an NVIDIA GPU, running Windows 7. I have a software module that is written in NVIDIA CUDA, and another module written in OpenCL. I would like to run the OpenCL module on the CPU, using the Intel implementation of OpenCL, and at the same time, use the CUDA module.

In my system I installed first the CUDA SDK, and then the SDK from Intel.

I've compiled the program in Visual Studio 2012, instructing the linker to use the Intel's library (and I compiled against the OpenCL headers provided by intel).

However when I run a simple program to query the hardware I'm only able to see the NVIDIA card.

I've tried modifying the Windows Registry, and the PATH variable, with no look. When I query the dependencies with "Dependecy Walker" I see that the program depends on a dll located in c:\windows\system32, which is not the folder where the Intel dll is. I've tried deleting this dll but I still see this dependency, and I'm only able to access the GPU.

Any idea about what could be happening?

Upvotes: 1

Views: 2364

Answers (2)

Dithermaster
Dithermaster

Reputation: 6343

On Windows, "OpenCL.dll" is the ICD provided by Khronos and redistributed by AMD, NVIDIA and Intel.

The actual drivers are referenced by the Registry, and the ICD enumerates them all.

When you query the OpenCL platforms, you'll see one for each installed driver (AMD, NVIDIA, Intel).

Within each platform there will be devices (or device), for example, in the NVIDIA platform you'll find your NVIDIA GPU and under the Intel platform you'll find your CPU.

Don't replace OpenCL.dll

Run clinfo or GPU-Z to see what OpenCL platforms and devices it sees.

Re-install the Intel CPU driver (a new one was just posted 2 days ago) to make sure their driver is installed.

Note: Your CPU needs to have SSE 4.2 for the Intel CPU driver to work.

Upvotes: 3

Michael Haidl
Michael Haidl

Reputation: 5482

You could try the Installable Client Driver (ICD) Loader. However, I have no experience if it works on Windows.

Or:

Since you don't want to use the GPU with OpenCL you can simply copy the Intel OpenCL.dll into your working directory. The working directory is visited first when .dlls are loaded. So, even if the Nvidia OpenCL.dll is installed into your windows/system32 directory the Intel library is found first and therefore loaded. There may be better solutions maybe load the dll on demand as discussed here Dynamically load a function from a DLL but as a fast solution it should work.

Upvotes: 1

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