How to install OpenCL on Windows

Posted by Anca Hamuraru on with 19 Comments

windows-start-openclGetting your Windows machine ready for OpenCL is rather straightforward. In short, you only need the latest drivers for your OpenCL device(s) and you’re ready to go. Of course, you will need to add an OpenCL SDK in case you want to develop OpenCL applications but that’s equally easy.

Before we start, a few notes:

  • The steps described herein have been tested on Windows 8.1 only, but should also apply for Windows 7 and Windows 8.
  • We will not discuss how to write an actual OpenCL program or kernel, but focus on how to get everything installed and ready for OpenCL on a Windows machine. This is because writing efficient OpenCL kernels is almost entirely OS independent.

If you want to know more about OpenCL and you are looking for simple examples to get started, check the Tutorials section on this webpage.

Running an OpenCL application

If you only need to run an OpenCL application without getting into development stuff then most probably everything already works.

If OpenCL applications fail to launch, then you need to have a closer look to the drivers and hardware installed on your machine:

GPU Caps Viewer
GPU Caps Viewer
  • Check that you have a device that supports OpenCL. All graphics cards and CPUs from 2011 and later support OpenCL. If your computer is from 2010 or before, check this page. You can also find a list with OpenCL conformant products on Khronos webpage.
  • Make sure your OpenCL device driver is up to date, especially if you’re not using the latest and greatest hardware. With certain older devices OpenCL support wasn’t initially included in the drivers.

Here is where you can download drivers manually:

  • Intel has hidden them a bit, but you can find them here with support for OpenCL 2.0.
  • AMD’s GPU-drivers include the OpenCL-drivers for CPUs, APUs and GPUs, version 2.0.
  • NVIDIA’s GPU-drivers mention mostly CUDA, but the drivers for OpenCL 1.1 1.2 are there too.

In addition, it is always a good idea to check for any other special requirements that the OpenCL application may have. Look for device type and OpenCL version in particular. For example, the application may run only on OpenCL CPUs, or conversely, on OpenCL GPUs. Or it may require a certain OpenCL version that your device does not support.

A great tool that will allow you to retrieve the details for the OpenCL devices in your system is Caps Viewer.

Developing OpenCL applications

Now it’s time to put the pedal to the metal and start developing some proper OpenCL applications.

The basic steps would be the following:

  • Make sure you have a machine which supports OpenCL, as described above.
  • Get the OpenCL headers and libraries included in the OpenCL SDK from your favourite vendor.
  • Start writing OpenCL code. That’s the difficult part.
  • Tell the compiler where the OpenCL headers are located.
  • Tell the linker where to find the OpenCL .lib files.
  • Build the fabulous application.
  • Run and prepare to be awed in amazement.

Ok, so let’s have a look into each of these.

OpenCL SDKs

For OpenCL headers and libraries the main options you can choose from are:

As long as you pay attention to the OpenCL version and the OpenCL features supported by your device, you can use the OpenCL headers and libraries from any of these three vendors.

OpenCL headers

Let’s assume that we are developing a 64bit C/C++ application using Visual Studio 2013. To begin with, we need to check how many OpenCL platforms are available in the system:

[raw]

#include<stdio.h>
#include<CL/cl.h>

int main(void)
{
    cl_int err;
    cl_uint numPlatforms;

    err = clGetPlatformIDs(0, NULL, &numPlatforms);
    if (CL_SUCCESS == err)
         printf("\nDetected OpenCL platforms: %d", numPlatforms);
    else
         printf("\nError calling clGetPlatformIDs. Error code: %d", err);

    return 0;
}

[/raw]

We need to specify where the OpenCL headers are located by adding the path to the OpenCL “CL” is in the same location as the other CUDA include files, that is, CUDA_INC_PATH. On a x64 Windows 8.1 machine with CUDA 6.5 the environment variable CUDA_INC_PATH is defined as “C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v6.5\include”

If you’re using the AMD SDK, you need to replace “$(CUDA_INC_PATH)” with “$(AMDAPPSDKROOT)/include” or, for Intel SDK, with “$(INTELOCLSDKROOT)/include“.

OpenCLNVIDIA_AdditionalInclude

OpenCL libraries

Similarly, we need to let the linker know about the OpenCL libraries. Firstly, add OpenCL.lib to the list of Additional Dependencies:

OpenCLNVIDIA_AdditionalDependencies

Secondly, specify the OpenCL.lib location in Additional Library Directories:

OpenCLNVIDIA_AdditionalLibrary

As in the case of the includes, If you’re using the AMD SDK, replace “$(CUDA_LIB_PATH)” with “$(AMDAPPSDKROOT)/lib/x86_64” , or in the case of Intel with “$(INTELOCLSDKROOT)/lib/x64“.

And you’re good to go! The application should now build and run. Now, just how difficult was it? Happy OpenCL-coding on Windows!

If you have any question or suggestion, just leave a comment.

Written by Anca Hamuraru

Anca Hamuraru joined StreamComputing in 2014, a collective of performance engineering experts.

Do you need expertise in High Performance Software? We have several experts available (HPC, GPGPU, OpenCL, HSA, CUDA, MPI, OpenMP) and can make any kind of algorithm run fast. Contact us via phone or mail to discuss further: +31 854865760 or contact@streamcomputing.eu

19 thoughts on “How to install OpenCL on Windows”

  2. Pingback: OpenCL Links vom 22.03.2015 - OpenCL-Blog

  3. Dithermaster

    NVIDIA’s drivers support OpenCL 1.2 on their recent hardware.

    • Gangadharan Esakki

      Yes it is a big mess since they have removed the OpenCL SDK separately from the main GPU computing tool kit and only OpenCL.lib file exists. Also there are separate OpenCL samples instead of one single ocl_releasevs2010.sln I ran my OpenCL 1.2 code on NVIDIA GeForce 840M

  4. Pingback: clGetPlatformID error when running OpenCL program. »

    • Anca Hamuraru Post author

      The problem is that you are providing a NULL pointer to clGetPlatformIDs.

      Try to change this line:
      cl_uint* numPlatforms = NULL;
      to
      cl_uint numPlatforms = 0;

      And call clGetPlaformIDs like this:
      clGetPlatformIDs(0, NULL, &numPlatforms);

      You are now saying to clGetPlatformsIDs: “Hey, I’m sending you the address of my variable numPlatforms, please write there the number of OpenCL platforms”.

      Please let us know if this change works for you.

  5. abdullahi

    Just wanna say a very big thank you to you, i was able to successfully install and run my first OpenCL program. wish u all the best..cheers

      • Nikko PSych

        please tell me how to get that 1st window OPENCL LIBRARIES.i dont know about any of these step.

        and i downloaded all the required downloads, but there is no exe file to open.all there was a bunch of useless dll etc files and folders.I have AMD gpu and INTEL cpu.

        ”Start writing OpenCL code. That’s the difficult part.” where to write, how can i get in to this step.

  6. Razorvashka

    Hi, guys. Tell me, please, how to activate OpenCL 1.1 for Intel Core 2 Quad Q9550 if OS Windows 10 – 64 bit?

  7. Priyangga Janmantara Anusasana

    Thanks for the tutorial, but i got these errors :

    any suggestion?

  8. Nikko PSych

    please tell me how to get that 1st window OPENCL LIBRARIES.i dont know about any of these step.
    and i downloaded all the required downloads, but there is no exe file to open.all there was a bunch of files.I have AMD gpu and INTEL cpu.
    ”Start writing OpenCL code. That’s the difficult part.” where to write, how can i get in to this step.

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