Question

I am experimenting with OpenCL programming. I was following the article in

http://www.thebigblob.com/getting-started-with-opencl-and-gpu-computing/

When the CPU is used ie CL_DEVICE_TYPE_DEFAULT it works fine.

Sample output:

...
1015 + 9 = 1024
1016 + 8 = 1024
1017 + 7 = 1024
1018 + 6 = 1024
1019 + 5 = 1024
1020 + 4 = 1024
1021 + 3 = 1024
1022 + 2 = 1024
1023 + 1 = 1024
...

However whenever I try to use the GPU (CL_DEVICE_TYPE_GPU) it doesn’t work.

Sample output:

...
1015 + 9 = 0
1016 + 8 = 0
1017 + 7 = 0
1018 + 6 = 0
1019 + 5 = 0
1020 + 4 = 0
1021 + 3 = 0
1022 + 2 = 0
1023 + 1 = 0
...

I have install AMD APP SDK 2.6 on my system which is running on a Core 2 Duo E4500 and the GPU is a HIS Radeon HD 5450.

Cheers,

Utsav

Answer 1

If you installed AMD APP SDK 2.6 then go to C:\Users\%USER%\Documents\AMD APP\samples\opencl\cl\app

There you will find ton of samples you can change the code to make it use GPU such as Template C where you can change the code to point to GPU when creating context

  context = clCreateContextFromType(cps, 
                                      CL_DEVICE_TYPE_GPU, 
                                      NULL, 
                                      NULL, 
                                      &status);

Some more checkpoint to make it work
1. Install the Latest AMD Catalayst Drivers from here : http://support.amd.com/us/gpudownload/Pages/index.aspx

1. Download GPU caps viewer and make sure your GPU devices are recognized.
   http://downloads.guru3d.com/GPU-Caps-Viewer-1.7.0-download-1584.html

HTH