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opencv performance in using opencl

asked 2017-01-11 15:46:34 -0600

babak12345 gravatar image

I'm programming in C++ using OpenCV 3.1.0. Also I'm new in OpenCV. I want to use OpenCL. Here is my code:

int _tmain(int argc, _TCHAR* argv[])
{
    clock_t t1, t2;
    Mat image;
    image = imread("...//myPic.jpg", CV_LOAD_IMAGE_GRAYSCALE);   // Read the file
    UMat u = image.getUMat(ACCESS_FAST);

    // calculating time with OpenCL
    cv::ocl::setUseOpenCL(true);
    t1 = clock();
    for (int i = 0; i < 1000; i++)
    {
        cv::Canny(u, u, 100, 50);
    }
    t2 = clock();

    // showing time with OpenCL
    double diff = ((double)t2 - (double)t1) / CLOCKS_PER_SEC;
    cout << "Running time with OpenCL: " << diff << endl;

    /////////////////////////////////////////////////////

    // calculating time with OpenCL
    cv::ocl::setUseOpenCL(false);
    t1 = clock();
    for (int i = 0; i < 1000; i++)
    {
        cv::Canny(u, u, 100, 50);
    }
    t2 = clock();

    // showing time with OpenCL
    diff = ((double)t2 - (double)t1) / CLOCKS_PER_SEC;
    cout << "Running time without OpenCL: " << diff << endl;

    getchar();

    return 0;
}

Here is the result of running code in my laptop.

Running time with OpenCL: 5.565
Running time without OpenCL: 2.441

As it is expected first value must be less than second one significantly but it is not. I test OpenCl technology using EmguCV 3.1 ( it is a wrapper for opencv) in C# and the result test show that it is 40 times faster than when I do not use OpenCl.

System info: Windows 8.1
Core i7 2.2GHz (2670QM)
Amd Radeon Graphic card (HD 6700M)
8GB RAM

Why the time with OpenCL is not what It should be expected?

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Comments

with your program my results are :

Running time with OpenCL: 2.066
Running time without OpenCL: 23.888
LBerger gravatar imageLBerger ( 2017-01-11 16:09:19 -0600 )edit

It is amazing! I get result like yours using EmguCV

babak12345 gravatar imagebabak12345 ( 2017-01-11 16:35:59 -0600 )edit

How can I check my environmental variables are set correctly?

babak12345 gravatar imagebabak12345 ( 2017-01-11 16:48:21 -0600 )edit

Did you compile OpenCV yourself or use an installer?

Tetragramm gravatar imageTetragramm ( 2017-01-11 20:22:11 -0600 )edit

Maybe the OpenCL code is runned on the Intel integrated GPU, if this CPU has one?

Eduardo gravatar imageEduardo ( 2017-01-12 15:41:36 -0600 )edit

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answered 2017-01-12 10:58:40 -0600

pklab gravatar image

Questions/answer

  1. What if using 2 different UMat like Canny(u, v, 100, 50); (Optimize memory transfers and initialization) ?
  2. What if Canny is called once before t1 = clock(); (OpenCL kernels initialization) ?

Here my results (Win7x64/OCV3.1x64/AMD Radeon6370)

                            | Your code | +Point 1  | +Point 2 |
----------------------------+-----------+-----------+----------+
Running time with OpenCL:   |    9.936  |   1.011   |   0.141  |
Running time without OpenCL:|   13.819  |  25.906   |  11.143  |

finally, collect info about your OpenCV and OpenCL

//INFO ABOUT OpenCV BUILD
cout << getBuildInformation();
// INFO ABOUT OpenCL
cout << "OpenCL: " << endl;
std::vector<ocl::PlatformInfo> platform_info;
cv::ocl::getPlatfomsInfo(platform_info);
for (size_t i = 0; i < platform_info.size(); i++)
{
    cout
        << "\tName: " << platform_info[i].name() << endl
        << "\tVendor: " << platform_info[i].vendor() << endl
        << "\tVersion: " << platform_info[i].version() << endl
        << "\tDevice Number: " << platform_info[i].deviceNumber() << endl
        << endl;
}

and compare them with your EmguCV

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Comments

And how to select particular opencl device that will be used by the opencv functions?

pi-null-mezon gravatar imagepi-null-mezon ( 2017-01-13 09:07:14 -0600 )edit
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Asked: 2017-01-11 15:46:34 -0600

Seen: 56 times

Last updated: Jan 12