我希望你一切都好,我的 opencl 程序有问题,我执行向量加法的以下程序
#define CL_USE_DEPRECATED_OPENCL_1_2APIS
#include <stdio.h>
#include <stdlib.h>
#include <CL/cl.h>
#define MAX_SOURCE_SIZE (0x100000)
int main(void) {
// Create the two input vectors
int i;
const int LIST_SIZE = 10;
int *A = (int*)malloc(sizeof(int)*LIST_SIZE);
int *B = (int*)malloc(sizeof(int)*LIST_SIZE);
for(i = 0; i < LIST_SIZE; i++) {
A[i] = i;
B[i] = LIST_SIZE - i;
}
// Load the kernel source code into the array source_str
FILE *fp;
char *source_str;
size_t source_size;
fp = fopen("vector_add_kernel.cl", "r");
if (!fp) {
fprintf(stderr, "Failed to load kernel.\n");
exit(1);
}
source_str = (char*)malloc(MAX_SOURCE_SIZE);
source_size = fread( source_str, 1, MAX_SOURCE_SIZE, fp);
fclose( fp );
// Get platform and device information
cl_platform_id platform_id = NULL;
cl_device_id device_id = NULL;
cl_uint ret_num_devices;
cl_uint ret_num_platforms;
cl_int ret = clGetPlatformIDs(1, &platform_id, &ret_num_platforms);
ret = clGetDeviceIDs( platform_id, CL_DEVICE_TYPE_CPU, 1,
&device_id, &ret_num_devices);
// Create an OpenCL context
cl_context context = clCreateContext( NULL, 1, &device_id, NULL, NULL, &ret);
// Create a command queue
cl_command_queue command_queue = clCreateCommandQueueWithProperties(context, device_id, 0, &ret);
// Create memory buffers on the device for each vector
cl_mem a_mem_obj = clCreateBuffer(context, CL_MEM_READ_ONLY,
LIST_SIZE * sizeof(int), NULL, &ret);
cl_mem b_mem_obj = clCreateBuffer(context, CL_MEM_READ_ONLY,
LIST_SIZE * sizeof(int), NULL, &ret);
cl_mem c_mem_obj = clCreateBuffer(context, CL_MEM_WRITE_ONLY,
LIST_SIZE * sizeof(int), NULL, &ret);
// Copy the lists A and B to their respective memory buffers
ret = clEnqueueWriteBuffer(command_queue, a_mem_obj, CL_TRUE, 0,
LIST_SIZE * sizeof(int), A, 0, NULL, NULL);
ret = clEnqueueWriteBuffer(command_queue, b_mem_obj, CL_TRUE, 0,
LIST_SIZE * sizeof(int), B, 0, NULL, NULL);
// Create a program from the kernel source
cl_program program = clCreateProgramWithSource(context, 1,
(const char **)&source_str, (const size_t *)&source_size, &ret);
// Build the program
ret = clBuildProgram(program, 1, &device_id, NULL, NULL, NULL);
// Create the OpenCL kernel
cl_kernel kernel = clCreateKernel(program, "vector_add", &ret);
// Set the arguments of the kernel
ret = clSetKernelArg(kernel, 0, sizeof(cl_mem), (void *)&a_mem_obj);
ret = clSetKernelArg(kernel, 1, sizeof(cl_mem), (void *)&b_mem_obj);
ret = clSetKernelArg(kernel, 2, sizeof(cl_mem), (void *)&c_mem_obj);
// Execute the OpenCL kernel on the list
size_t global_item_size = LIST_SIZE; // Process the entire lists
size_t local_item_size = 64; // Divide work items into groups of 64
ret = clEnqueueNDRangeKernel(command_queue, kernel, 1, NULL,
&global_item_size, &local_item_size, 0, NULL, NULL);
// Read the memory buffer C on the device to the local variable C
int *C = (int*)malloc(sizeof(int)*LIST_SIZE);
ret = clEnqueueReadBuffer(command_queue, c_mem_obj, CL_TRUE, 0,
LIST_SIZE * sizeof(int), C, 0, NULL, NULL);
// Display the result to the screen
for(i = 0; i < LIST_SIZE; i++)
printf("%d + %d = %d\n", A[i], B[i], C[i]);
// Clean up
ret = clFlush(command_queue);
ret = clFinish(command_queue);
ret = clReleaseKernel(kernel);
ret = clReleaseProgram(program);
ret = clReleaseMemObject(a_mem_obj);
ret = clReleaseMemObject(b_mem_obj);
ret = clReleaseMemObject(c_mem_obj);
ret = clReleaseCommandQueue(command_queue);
ret = clReleaseContext(context);
free(A);
free(B);
free(C);
return 0;
}
使用以下内核:
__kernel void vector_add(__global int *A, __global int *B, __global int *C) {
// Get the index of the current element
int i = get_global_id(0);
// Do the operation
C[i] = A[i] + B[i];
printf("calcule effectué");
}
在运行 C 程序时,我得到以下结果,我似乎无法弄清楚为什么
0 + 10 = 714121520
1 + 9 = 21995
2 + 8 = 0
3 + 7 = 0
4 + 6 = 1852255608
5 + 5 = 1768697717
6 + 4 = 1932425826
7 + 3 = 3223151
8 + 2 = 1919885413
9 + 1 = 1953459744
不知道是什么问题,求大神帮忙!!!
回答1
我也得到错误的结果,而且每次执行的结果都是随机的。这意味着 C
数组中的 values 永远不会被覆盖,并且会打印分配的内存位置中未初始化的随机 values。
调试的第一步是打印 ret
并查看哪里出了问题:
- 在
clGetDeviceIDs
之后出现错误 -1(未找到设备)。CL_DEVICE_TYPE_ALL
清除;然后选择的设备是我的 Nvidia GPU。 - 在
clCreateProgramWithSource
之后出现错误 -6(主机内存不足)。要解决此问题,请使用cl_program program = clCreateProgramWithSource(context, 1, (const char**)&source_str, NULL, &ret);
。 - 在
clEnqueueNDRangeKernel
之后出现错误 -54(无效的工作组大小)。要解决此问题,请将global_item_size
设为local_item_size
的倍数:size_t global_item_size = ((LIST_SIZE+local_item_size-1)/local_item_size)*local_item_size;
。由于您预期的全局大小(或者更确切地说分配缓冲区的大小)不是工作组大小的倍数,因此您还应该在内核中放置一个保护子句if(i>=10) return;
;否则内核可能会在未定义的内存空间中写入 values ,这可能会导致崩溃。
然后,一切都按预期工作。这是整个固定代码:
#define CL_USE_DEPRECATED_OPENCL_1_2APIS
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <CL/cl.h>
#define MAX_SOURCE_SIZE (0x100000)
int main(void) {
// Create the two input vectors
int i;
const int LIST_SIZE = 10;
int* A = (int*)malloc(sizeof(int)*LIST_SIZE);
int* B = (int*)malloc(sizeof(int)*LIST_SIZE);
int* C = (int*)malloc(sizeof(int)*LIST_SIZE);
for(i = 0; i < LIST_SIZE; i++) {
A[i] = i;
B[i] = LIST_SIZE - i;
C[i] = 0;
}
// Load the kernel source code into the array source_str
size_t source_size;
const char* source_str =
"__kernel void vector_add(__global int *A, __global int *B, __global int *C) {\n"
" int i = get_global_id(0);\n"
" if(i>=10) return;\n"
" C[i] = A[i]+B[i];\n"
"}"
;
// Get platform and device information
cl_platform_id platform_id = NULL;
cl_device_id device_id = NULL;
cl_uint ret_num_devices;
cl_uint ret_num_platforms;
cl_int ret = clGetPlatformIDs(1, &platform_id, &ret_num_platforms);
ret = clGetDeviceIDs(platform_id, CL_DEVICE_TYPE_ALL, 1,
&device_id, &ret_num_devices);
// Create an OpenCL context
cl_context context = clCreateContext(NULL, 1, &device_id, NULL, NULL, &ret);
std::cout << "context " << ret << std::endl;
// Create a command queue
cl_command_queue command_queue = clCreateCommandQueue(context, device_id, 0, &ret);
std::cout << "queue " << ret << std::endl;
// Create memory buffers on the device for each vector
cl_mem a_mem_obj = clCreateBuffer(context, CL_MEM_READ_ONLY,
LIST_SIZE * sizeof(int), NULL, &ret);
cl_mem b_mem_obj = clCreateBuffer(context, CL_MEM_READ_ONLY,
LIST_SIZE * sizeof(int), NULL, &ret);
cl_mem c_mem_obj = clCreateBuffer(context, CL_MEM_WRITE_ONLY,
LIST_SIZE * sizeof(int), NULL, &ret);
std::cout << "buffer " << ret << std::endl;
// Copy the lists A and B to their respective memory buffers
ret = clEnqueueWriteBuffer(command_queue, a_mem_obj, CL_TRUE, 0,
LIST_SIZE * sizeof(int), A, 0, NULL, NULL);
ret = clEnqueueWriteBuffer(command_queue, b_mem_obj, CL_TRUE, 0,
LIST_SIZE * sizeof(int), B, 0, NULL, NULL);
std::cout << "write " << ret << std::endl;
// Create a program from the kernel source
cl_program program = clCreateProgramWithSource(context, 1, (const char**)&source_str, NULL, &ret);
//cl_program program = clCreateProgramWithSource(context, 1, (const char**)&source_str, (const size_t *)&source_size, &ret);
std::cout << "program " << ret << std::endl;
// Build the program
ret = clBuildProgram(program, 1, &device_id, NULL, NULL, NULL);
// Create the OpenCL kernel
cl_kernel kernel = clCreateKernel(program, "vector_add", &ret);
std::cout << "kernel " << ret << std::endl;
// Set the arguments of the kernel
ret = clSetKernelArg(kernel, 0, sizeof(cl_mem), (void*)&a_mem_obj);
ret = clSetKernelArg(kernel, 1, sizeof(cl_mem), (void*)&b_mem_obj);
ret = clSetKernelArg(kernel, 2, sizeof(cl_mem), (void*)&c_mem_obj);
std::cout << "args " << ret << std::endl;
// Execute the OpenCL kernel on the list
size_t local_item_size = 64; // Divide work items into groups of 64
size_t global_item_size = ((LIST_SIZE+local_item_size-1)/local_item_size)*local_item_size; // make global range a multiple of local range
ret = clEnqueueNDRangeKernel(command_queue, kernel, 1, NULL, &global_item_size, &local_item_size, 0, NULL, NULL);
std::cout << "run " << ret << std::endl;
clFinish(command_queue);
// Read the memory buffer C on the device to the local variable C
ret = clEnqueueReadBuffer(command_queue, c_mem_obj, CL_TRUE, 0,
LIST_SIZE * sizeof(int), C, 0, NULL, NULL);
std::cout << "read " << ret << std::endl;
// Display the result to the screen
for(i = 0; i < LIST_SIZE; i++)
printf("%d + %d = %d\n", A[i], B[i], C[i]);
// Clean up
ret = clFlush(command_queue);
ret = clFinish(command_queue);
ret = clReleaseKernel(kernel);
ret = clReleaseProgram(program);
ret = clReleaseMemObject(a_mem_obj);
ret = clReleaseMemObject(b_mem_obj);
ret = clReleaseMemObject(c_mem_obj);
ret = clReleaseCommandQueue(command_queue);
ret = clReleaseContext(context);
free(A);
free(B);
free(C);
return 0;
}
调试很麻烦。帮自己一个忙,将这个 https://github.com/ProjectPhysX/OpenCL-Wrapper 与 C++ 一起使用。这消除了所有代码开销以及随之而来的无数错误可能性。