why halide blur algorithm is slower than the blur by opencv

[halcomcn]

loop 30 times, compare infos output:

image channel: 1
Halide Elapsed time: 7274 ms
Opencv Elapsed time: 23 ms
Halide: Done

someone can help me to explain it?
I am first time to coding halide program. thanks.

I had try some schedule to speed up, but halide is slower than opencv, it is so weird.

if I want to speed up, how can I modify these codes to get good result.

int main()
{
    cv::Mat image;
    image = imread("C:\\AIOCRProjects\\Image\\1 (1).jpg", 0); // GrayImage
    std::cout << "image channel: " << image.channels() << std::endl;

    ////////////////////////////////////////////////////////////
    auto startH = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < 30; i++)
    {
        // Halide-17.0.1-x86-64-windows C++ --> Win10+64bit+VS2022
        cv::Mat HalideBlur;
        HalideBlur = aiPredict.BlurHal(image);
        cv::Mat HalideThreshold;
        HalideThreshold = aiPredict.ThresholdHal(HalideBlur, 128.0f);
    }
    auto endH = std::chrono::high_resolution_clock::now();
    auto durationH = std::chrono::duration_cast<std::chrono::milliseconds>(endH - startH);
    std::cout << "Halide Elapsed time: " << durationH.count() << " ms" << std::endl;
    //
    auto startO = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < 30; i++)
    {
        // opencv C++ --> Win10+64bit+VS2022
        cv::Mat opencvBlur;
        cv::blur(image, opencvBlur, cv::Size(3, 3));
        cv::Mat opencvThreshold;
        cv::threshold(opencvBlur, opencvThreshold, 128.0, 255.0, cv::THRESH_BINARY);
    }
    auto endO = std::chrono::high_resolution_clock::now();
    auto durationO = std::chrono::duration_cast<std::chrono::milliseconds>(endO - startO);
    std::cout << "Opencv Elapsed time: " << durationO.count() << " ms" << std::endl;
    ////////////////////////////////////////////////////////////
    std::cout << "Halide: " << "Done" << std::endl;

}

[halcomcn]

need to learn it step by step. it is more much faster