如何销毁 CUDA 图形数据类型

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【中文标题】如何销毁 CUDA 图形数据类型【英文标题】：How to destroy CUDA graphics datatypes 【发布时间】：2020-12-06 20:23:08 【问题描述】：

我使用函数从一些 RGB 数据创建 OpenGL 纹理/CUDA 表面对。 cudaSurfaceObject_t 可用于 CUDA 内核，用于 GPU 加速的图像处理，GLuint 可用于渲染 CUDA 内核的结果。该函数在下面的程序中提供：



#include <glad/glad.h>
#include <GLFW/glfw3.h>

#include <cudaGL.h>
#include <cuda_gl_interop.h>

#include <iostream>



#define cudaCheckError()  \
    cudaError_t err = cudaGetLastError(); \
    if(err != cudaSuccess)  \
      printf("Cuda error: %s:%d: %s\n", __FILE__, __LINE__, cudaGetErrorString(err)); \
      exit(1); \
     \
  

void createTextureSurfacePair(int width, int height, uint8_t* const data, GLuint& textureOut, cudaGraphicsResource_t& graphicsResourceOut, cudaSurfaceObject_t& surfaceOut) 

    // Create the OpenGL texture that will be displayed with GLAD and GLFW
    glGenTextures(1, &textureOut);
    // Bind to our texture handle
    glBindTexture(GL_TEXTURE_2D, textureOut);
    // Set texture interpolation methods for minification and magnification
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    // Set texture clamping method
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
    // Create the texture and its attributes
    glTexImage2D(GL_TEXTURE_2D,     // Type of texture
        0,                // Pyramid level (for mip-mapping) - 0 is the top level
        GL_RGBA,          // Internal color format to convert to
        width,            // Image width  i.e. 640 for Kinect in standard mode
        height,           // Image height i.e. 480 for Kinect in standard mode
        0,                // Border width in pixels (can either be 1 or 0)
        GL_BGR,          // Input image format (i.e. GL_RGB, GL_RGBA, GL_BGR etc.)
        GL_UNSIGNED_BYTE, // Image data type.
        data);            // The actual image data itself
    //Note that the type of this texture is an RGBA UNSIGNED_BYTE type. When CUDA surfaces
    //are synchronized with OpenGL textures, the surfaces will be of the same type.
    //They won't know or care about their data types though, for they are all just byte arrays
    //at heart. So be careful to ensure that any CUDA kernel that handles a CUDA surface
    //uses it as an appropriate type. You will see that the update_surface kernel (defined 
    //above) treats each pixel as four unsigned bytes along the X-axis: one for red, green, blue,
    //and alpha respectively.

    //Create the CUDA array and texture reference
    cudaArray* bitmap_d;
    //Register the GL texture with the CUDA graphics library. A new cudaGraphicsResource is created, and its address is placed in cudaTextureID.
    //Documentation: https://docs.nvidia.com/cuda/cuda-runtime-api/group__CUDART__OPENGL.html#group__CUDART__OPENGL_1g80d12187ae7590807c7676697d9fe03d
    cudaGraphicsGLRegisterImage(&graphicsResourceOut, textureOut, GL_TEXTURE_2D,
        cudaGraphicsRegisterFlagsNone);
    cudaCheckError();
    //Map graphics resources for access by CUDA.
    //Documentation: https://docs.nvidia.com/cuda/cuda-runtime-api/group__CUDART__INTEROP.html#group__CUDART__INTEROP_1gad8fbe74d02adefb8e7efb4971ee6322
    cudaGraphicsMapResources(1, &graphicsResourceOut, 0);
    cudaCheckError();
    //Get the location of the array of pixels that was mapped by the previous function and place that address in bitmap_d
    //Documentation: https://docs.nvidia.com/cuda/cuda-runtime-api/group__CUDART__INTEROP.html#group__CUDART__INTEROP_1g0dd6b5f024dfdcff5c28a08ef9958031
    cudaGraphicsSubResourceGetMappedArray(&bitmap_d, graphicsResourceOut, 0, 0);
    cudaCheckError();
    //Create a CUDA resource descriptor. This is used to get and set attributes of CUDA resources.
    //This one will tell CUDA how we want the bitmap_surface to be configured.
    //Documentation for the struct: https://docs.nvidia.com/cuda/cuda-runtime-api/structcudaResourceDesc.html#structcudaResourceDesc
    struct cudaResourceDesc resDesc;
    //Clear it with 0s so that some flags aren't arbitrarily left at 1s
    memset(&resDesc, 0, sizeof(resDesc));
    //Set the resource type to be an array for convenient processing in the CUDA kernel.
    //List of resTypes: https://docs.nvidia.com/cuda/cuda-runtime-api/group__CUDART__TYPES.html#group__CUDART__TYPES_1g067b774c0e639817a00a972c8e2c203c
    resDesc.resType = cudaResourceTypeArray;
    //Bind the new descriptor with the bitmap created earlier.
    resDesc.res.array.array = bitmap_d;
    //Create a new CUDA surface ID reference.
    //This is really just an unsigned long long.
    //Docuentation: https://docs.nvidia.com/cuda/cuda-runtime-api/group__CUDART__TYPES.html#group__CUDART__TYPES_1gbe57cf2ccbe7f9d696f18808dd634c0a
    surfaceOut = 0;
    //Create the surface with the given description. That surface ID is placed in bitmap_surface.
    //Documentation: https://docs.nvidia.com/cuda/cuda-runtime-api/group__CUDART__SURFACE__OBJECT.html#group__CUDART__SURFACE__OBJECT_1g958899474ab2c5f40d233b524d6c5a01
    cudaCreateSurfaceObject(&surfaceOut, &resDesc);
    cudaCheckError();



void initGL() 

    // Setup window
    if (!glfwInit())
        return;

    // Decide GL+GLSL versions
#if __APPLE__
    // GL 3.2 + GLSL 150
    const char* glsl_version = "#version 150";
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // Required on Mac
#else
    // GL 3.0 + GLSL 130
    const char* glsl_version = "#version 130";
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
    //glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
    //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // 3.0+ only
#endif

    // Create window with graphics context
    GLFWwindow* currentGLFWWindow = glfwCreateWindow(1280, 720, "Raytracing in One Weekend", NULL, NULL);
    if (currentGLFWWindow == NULL)
        return;
    glfwMakeContextCurrent(currentGLFWWindow);
    glfwSwapInterval(3); // Enable vsync

    if (!gladLoadGL()) 
        // GLAD failed
        printf( "GLAD failed to initialize :(" );
        return;
    



int main() 
    initGL();

    int size = 500;

    uint8_t* data = new uint8_t[size * size * 3]; //dummy 100x100 RGB image

    cudaSurfaceObject_t a;
    cudaGraphicsResource_t b;
    GLuint c;

    for (int i = 0; i < 10000; i++) 
/*------ATTEMPT TO CREATE CUDA SURFACE AND OPENGL TEXTURE------------*/
        createTextureSurfacePair(size, size, data, c, b, a);

/*------ATTEMPT TO DESTROY CUDA SURFACE AND OPENGL TEXTURE------------*/
        //Destroy surface
        cudaDestroySurfaceObject(a);
        //Destroy graphics resource
        cudaGraphicsUnmapResources(1, &b);
        //Destroy texture
        glDeleteTextures(1, &c);

        if (i % 100 == 0) printf("Iteration %d\n", i);

此程序中似乎存在内存泄漏，因为它会导致专用 GPU 内存迅速增加，直到程序崩溃。 main 函数中我没有销毁什么？

【问题讨论】：

不问显而易见的问题，您确定这真的是内存泄漏吗？有很多操作会导致一次性内存分配，看起来像是泄漏。释放和销毁东西不会释放内存也是正常的 @talonmies 在我看来这是内存泄漏。当我使用这些函数重复分配和取消分配纹理/表面对时，RAM 消耗稳步增加到至少几 GB。这发生在 CPU RAM 和专用 GPU RAM 中。在程序终止之前，不会释放任何内存。 更新：这是一个更大项目的一部分，现在我相信大部分问题都出在其他地方。当我隔离这段代码时，CPU RAM 并没有显着增加，但经过大约 5000 次迭代后，GPU 专用 RAM 增加到了 ~600MB。 这个问题现在已经用更简洁的代码重写了（即写了一个新程序，只是为了多次生成和销毁这三种数据结构），但问题仍然存在，我不'无权再次打开问题。 我不建议这样做：//Omitted for brevity 你发布的不是minimal reproducible example，这会让其他人更难帮助你。 【参考方案1】：

当我添加以下行时：

cudaGraphicsUnregisterResource(b);

在代码中的这一行之后：

cudaGraphicsUnmapResources(1, &b);

您的程序为我运行完成（即它运行了指定的 10000 次循环）而没有抛出任何错误。在cuda-memcheck下运行时也能正常运行。

This function 是cudaGraphicsGLRegisterImage 的“毁灭者”。您可以通过以下方式了解可能是这种情况：

    研究使用 CUDA/OpenGL 互操作的各种 CUDA 示例代码（例如 simpleGLES、postProcessGL、imageDenoisingGL、bilateralFilter 等）。

    参考runtime API docs for cudaGraphicsGLRegisterImage，并注意它在函数描述的底部列出：

另请参阅： cudaGraphicsUnregisterResource、cudaGraphicsMapResources、cudaGraphicsSubResourceGetMappedArray、cuGraphicsGLRegisterImage

【讨论】：

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