在openCL中創建子緩衝區

Question

我想在OpenCL中運行我的第一個代碼。爲了創建子緩衝區，我從「OpenCL in Action」一書中獲得了以下代碼。該代碼給我錯誤的子緩衝區創建失敗。我的電腦有一個Intel CPU和NVIDIA GPU。但是，當我在另一臺具有AMD CPU和GPU的計算機上運行代碼時，它工作正常。任何想法爲什麼這個代碼不適用於非AMD平臺？ 以下是錯誤：

，這是代碼：

#include <stdio.h> 
#include <stdlib.h> 
#include <sys/types.h> 

#ifdef MAC 
#include <OpenCL/cl.h> 
#else 
#include <CL/cl.h> 
#endif 

/* Find a GPU or CPU associated with the first available platform */ 
cl_device_id create_device() { 

    cl_platform_id platform; 
    cl_device_id dev; 
    int err; 


    /* Identify a platform */ 
    err = clGetPlatformIDs(1, &platform, NULL); 
    if (err < 0) { 
     perror("Couldn't identify a platform"); 
     exit(1); 
    } 

    /* Access a device */ 
    err = clGetDeviceIDs(platform, CL_DEVICE_TYPE_GPU, 1, &dev, NULL); 
    if (err == CL_DEVICE_NOT_FOUND) { 
     err = clGetDeviceIDs(platform, CL_DEVICE_TYPE_CPU, 1, &dev, NULL); 
    } 
    if (err < 0) { 
     perror("Couldn't access any devices"); 
     exit(1); 
    } 

    return dev; 
} 

int main() { 

    /* Host/device data structures */ 
    cl_device_id device; 
    cl_context context; 
    cl_int err; 

    /* Data and buffers */ 
    float main_data[100] = {}; 
    cl_mem main_buffer, sub_buffer; 
    void *main_buffer_mem = NULL, *sub_buffer_mem = NULL; 
    size_t main_buffer_size, sub_buffer_size; 
    cl_buffer_region region; 

    /* Create device and context */ 
    device = create_device(); 
    context = clCreateContext(NULL, 1, &device, NULL, NULL, &err); 
    if (err < 0) { 
     perror("Couldn't create a context"); 
     exit(1); 
    } 

    /* Create a buffer to hold 100 floating-point values */ 
    main_buffer = clCreateBuffer(context, CL_MEM_READ_ONLY | 
     CL_MEM_COPY_HOST_PTR, sizeof(main_data), main_data, &err); 
    if (err < 0) { 
     perror("Couldn't create a buffer"); 
     exit(1); 
    } 

    /* Create a sub-buffer */ 
    /* Modified on 2/12/2014 to account for unaligned memory error */ 
    region.origin = 0 * sizeof(float); 
    region.size = 20 * sizeof(float); 
    sub_buffer = clCreateSubBuffer(main_buffer, CL_MEM_READ_ONLY | 
     CL_MEM_COPY_HOST_PTR, CL_BUFFER_CREATE_TYPE_REGION, &region, &err); 
    if (err < 0) { 
     perror("Couldn't create a sub-buffer."); 
     exit(1); 
    } 

    /* Obtain size information about the buffers */ 
    clGetMemObjectInfo(main_buffer, CL_MEM_SIZE, 
     sizeof(main_buffer_size), &main_buffer_size, NULL); 
    clGetMemObjectInfo(sub_buffer, CL_MEM_SIZE, 
     sizeof(sub_buffer_size), &sub_buffer_size, NULL); 
    printf("Main buffer size: %lu\n", main_buffer_size); 
    printf("Sub-buffer size: %lu\n", sub_buffer_size); 

    /* Obtain the host pointers */ 
    clGetMemObjectInfo(main_buffer, CL_MEM_HOST_PTR, sizeof(main_buffer_mem), 
     &main_buffer_mem, NULL); 
    clGetMemObjectInfo(sub_buffer, CL_MEM_HOST_PTR, sizeof(sub_buffer_mem), 
     &sub_buffer_mem, NULL); 
    printf("Main buffer memory address: %p\n", main_buffer_mem); 
    printf("Sub-buffer memory address: %p\n", sub_buffer_mem); 

    /* Print the address of the main data */ 
    printf("Main array address: %p\n", main_data); 

    /* Deallocate resources */ 
    clReleaseMemObject(main_buffer); 
    clReleaseMemObject(sub_buffer); 
    clReleaseContext(context); 

    return 0; 
} 

Answer 1

既然你已經分配時main_buffer創建緩衝區的內存，你不需要做再次獲取子緩衝區時。您應該只作爲CL_MEM_READ_ONLYcl_mem_flags：

sub_buffer = clCreateSubBuffer(main_buffer, CL_MEM_READ_ONLY, 
           CL_BUFFER_CREATE_TYPE_REGION, &region, &err);