opencl映射内存不起作用
我尝试在我的OpenCL程序中实现内存映射技术，但它不起作用！ 这是我的内核代码：
__kernel void update(__global char *in, __global char *out) { size_t i; for (i = 0; i < 10; i++); out[i] += 'A' - 'a'; } 这是主机代码：
cl_platform_id platformId = NULL; cl_device_id deviceId = NULL; cl_context context = NULL; cl_command_queue commandQueue = NULL; cl_mem cmPinnedBufIn = NULL; cl_mem cmPinnedBufOut = NULL; cl_mem cmDevBufIn = NULL; cl_mem cmDevBufOut = NULL; unsigned char *cDataIn = NULL; unsigned char *cDataOut = NULL; cl_program program = NULL; cl_kernel kernel = NULL; cl_uint retNumDevices; cl_uint retNumPlatforms; cl_int ret; cl_event event; cl_ulong start; cl_ulong end; size_t group_size = GLOBAL_ITEM_SIZE / LOCAL_ITEM_SIZE; FILE *fp; const char fileName[] = "./update.cl"; size_t sourceSize; char *sourceStr; unsigned char tt[10]; /* Load kernel source file */ if ( !(fp = fopen(fileName, "r")) ) quitErr("Failed to load kernel.", EXIT_FAILURE); sourceStr = (char *)malloc(MAX_SOURCE_SIZE); sourceSize = fread(sourceStr, 1, MAX_SOURCE_SIZE, fp); fclose(fp); /* Get Platform/Device Information */ ret = clGetPlatformIDs(1, &platformId, &retNumPlatforms); assert(ret == CL_SUCCESS); ret = clGetDeviceIDs(platformId, CL_DEVICE_TYPE_GPU, 1, &deviceId, &retNumDevices); assert(ret == CL_SUCCESS); /* Create OpenCL Context */ context = clCreateContext( NULL, retNumDevices, &deviceId, NULL, NULL, &ret); /* Create command queue with measurment of preformance */ commandQueue = clCreateCommandQueue(context, deviceId, CL_QUEUE_PROFILING_ENABLE, &ret); /* Create buffer objects */ size_t memSize = 10 * sizeof(unsigned char); cmPinnedBufIn = clCreateBuffer(context, CL_MEM_READ_WRITE | CL_MEM_ALLOC_HOST_PTR, memSize, NULL, &ret); assert(ret == CL_SUCCESS); cmPinnedBufOut = clCreateBuffer(context, CL_MEM_READ_WRITE | CL_MEM_ALLOC_HOST_PTR, memSize, NULL, &ret); assert(ret == CL_SUCCESS); /* Mapp pinned memmory */ cDataIn = (unsigned char *)clEnqueueMapBuffer(commandQueue, cmPinnedBufIn, CL_TRUE, CL_MAP_WRITE, 0, memSize, 0, NULL, NULL, &ret); assert(ret == CL_SUCCESS); /* Initialize data */ for (size_t w = 0; w < memSize; w++) cDataIn[w] = 'a' + w; /* Create kernel program from source file */ program = clCreateProgramWithSource(context, 1, (const char **)&sourceStr, (const size_t *)&sourceSize, &ret); assert(ret == CL_SUCCESS); ret = clBuildProgram(program, 1, &deviceId, NULL, NULL, NULL); if (ret != CL_SUCCESS) { error("\nFail to build the program\n"); char buffer[10240]; clGetProgramBuildInfo(program, deviceId, CL_PROGRAM_BUILD_LOG, sizeof(buffer), buffer, NULL); quitErr(buffer, EXIT_FAILURE); } /* Create data parallel OpenCL kernel */ kernel = clCreateKernel(program, "update", &ret); assert(ret == CL_SUCCESS); /* Set OpenCL kernel arguments */ ret = clSetKernelArg(kernel, 0, sizeof(cl_mem), (void *)&cmPinnedBufIn); assert(ret == CL_SUCCESS); ret = clSetKernelArg(kernel, 1, sizeof(cl_mem), (void *)&cmPinnedBufOut); assert(ret == CL_SUCCESS); size_t global_item_size = GLOBAL_ITEM_SIZE; size_t local_item_size = LOCAL_ITEM_SIZE; /* Execute OpenCL kernel as data parallel */ ret = clEnqueueNDRangeKernel(commandQueue, kernel, 1, NULL, &global_item_size, &local_item_size, 0, NULL, &event); if (ret == CL_INVALID_WORK_GROUP_SIZE) quitErr("Invalid work group size: error when compute group size.", EXIT_FAILURE); assert(ret == CL_SUCCESS); /* Execute measurment issue */ if (preformanceMeas) { clWaitForEvents(1, &event); clGetEventProfilingInfo(event, CL_PROFILING_COMMAND_START, sizeof(cl_ulong), &start, NULL); clGetEventProfilingInfo(event, CL_PROFILING_COMMAND_END, sizeof(cl_ulong), &end, NULL); printf("Kernels execution time: %10.6f [ms]\n", (end - start) * 1.0e-6f); } cDataOut = (unsigned char *)clEnqueueMapBuffer(commandQueue, cmPinnedBufOut, CL_TRUE, CL_MAP_READ, 0, memSize, 0, NULL, NULL, &ret); assert(ret == CL_SUCCESS); /* Transfer result to host */ memcpy(tt, cDataOut, memSize); /* Transfer measurment issue */ if (preformanceMeas) { //clWaitForEvents(1, &event); clGetEventProfilingInfo(event, CL_PROFILING_COMMAND_START, sizeof(cl_ulong), &start, NULL); clGetEventProfilingInfo(event, CL_PROFILING_COMMAND_END, sizeof(cl_ulong), &end, NULL); printf("Memory x buffer read: %10.6f [ms]\n", (end - start) * 1.0e-6f); } /* Display Results */ int i; for (i = 0; i < group_size; i++) for (size_t x = 0; x < memSize; x++) printf("%c", tt[x]); printf("\n"); /* Finalization */ clFlush(commandQueue); clFinish(commandQueue); clReleaseKernel(kernel); clReleaseProgram(program); clReleaseMemObject(cmPinnedBufIn); clReleaseMemObject(cmPinnedBufOut); clReleaseMemObject(cmDevBufIn); clReleaseMemObject(cmDevBufOut); clReleaseCommandQueue(commandQueue); clReleaseContext(context); free(sourceStr); return EXIT_SUCCESS;
内核将小写字符更改为大写，但我的输出为空。 当我静态分配内核中的字符时，如下所示：
__kernel void update(__global char *in, __global char *out) { size_t i; for (i = 0; i < 10; i++) out[i] = 'A' + i; }
比结果还可以。 因此，我从输入数据得出的结论是没有正确地传输到内存，但为什么呢？ 有人可以帮我吗？
在映射缓冲区中写入输入后，必须调用clEnqueueUnmapMemObject 。 参见OpenCL 1.1规范，5.4.2.1。
您的内核不会访问，也不依赖于线程索引get_global_id(0) 。 你可能想要这样的东西：
size_t i = get_global_id(0) char c = in[i]; out[i] = (c>='a' && c<='z')?(c + 'A' - 'a'):c;
要在OpenCL 1.0中编写char数组，需要启用byte_addressable_store extension.r
内核的for循环有一个最后的“;”，所以它是一个空循环。
for (i = 0; i < 10; i++);