1、释放资源的函数是:clRelaseResource ,比如: clReleaseProgram(), clReleaseMemObject()等。错误捕捉:如果OpenCL函数执行失败,会返回一个错误码,一般是个负值,返回0则表示执行成功。我们可以根据该错误码知道什么地方出错了,需要修改。错误码在cl.h中定义,下面是几个错误码的例子.CL_DEVICE_NOT_FOUND -1CL_DEVICE_NOT_AVAILABLE -2CL_COMPILER_NOT_AVAILABLE -3CL_MEM_OBJECT_ALLOCATION_FAILURE -4下面是一个OpenCL机制的示意图程序模
2、型数据并行:work item和内存对象元素之间是一一映射关系;workgroup可以显示指定,也可以隐式指定。任务并行:kernel的执行独立于线程索引空间;用其他方法表示并行,比如把不同的任务放入队列,用设备指定的特殊的向量类型等等。同步:workgroup内work item之间的同步;命令队列中不同命令之间的同步。完整代码如下: #include stdafx.h #include stdio.hstdlib.htime.h 6:iostream 7:fstream 8: 9: using namespace std; 10: #define NWITEMS 262144 11: 12
3、: #pragma comment (lib,OpenCL.lib) 13: 14: /把文本文件读入一个string中 15: int convertToString(const char *filename, std:string& s) 16: 17: size_t size; 18: char* str; 19: 20: std:fstream f(filename, (std:fstream:in | std:binary); 21: 22: if(f.is_open() 23: 24: size_t fileSize; 25: f.seekg(0, std:end); 26: si
4、ze = fileSize = (size_t)f.tellg(); 27:beg); 28: 29: str = new charsize+1; 30: if(!str) 31: 32: f.close(); 33: return NULL; 34: 35: 36: f.read(str, fileSize); 37: 38: strsize = 0; 39: 40: s = str; 41: delete str; 42: return 0; 43: 44: printf(Error: Failed to open file %sn, filename); 45: return 1; 46
5、: 47: 48: int main(int argc, char* argv) 49: 50: /在host内存中创建三个缓冲区 51: float *buf1 = 0; 52: float *buf2 = 0; 53: float *buf = 0; 54: 55: buf1 =(float *)malloc(NWITEMS * sizeof(float); 56: buf2 =(float *)malloc(NWITEMS * sizeof(float); 57: buf =(float *)malloc(NWITEMS * sizeof(float); 58: 59: /初始化buf1
6、和buf2的内容 60: int i; 61: srand( (unsigned)time( NULL ) ); 62: for(i = 0; i NWITEMS; i+) 63: buf1i = rand()%65535; 64: 65: srand( (unsigned)time( NULL ) +1000); 66: 67: buf2i = rand()%65535; 68: 69: 70: bufi = buf1i + buf2i; 71: 72: cl_uint status; 73: cl_platform_id platform; 74: 75: /创建平台对象 76: stat
7、us = clGetPlatformIDs( 1, &platform, NULL ); 77: 78: cl_device_id device; 79: 80: /创建GPU设备 81: clGetDeviceIDs( platform, CL_DEVICE_TYPE_GPU, 82: 1, 83: &device, 84: NULL); 85: /创建context 86: cl_context context = clCreateContext( NULL, 87: 88: 89: NULL, NULL, NULL); 90: /创建命令队列 91: cl_command_queue q
8、ueue = clCreateCommandQueue( context, 92: device, 93: CL_QUEUE_PROFILING_ENABLE, NULL ); 94: /创建三个OpenCL内存对象,并把buf1的内容通过隐式拷贝的方式 95: /拷贝到clbuf1,buf2的内容通过显示拷贝的方式拷贝到clbuf2 96: cl_mem clbuf1 = clCreateBuffer(context, 97: CL_MEM_READ_ONLY | CL_MEM_COPY_HOST_PTR, 98: NWITEMS*sizeof(cl_float),buf1, 99: NUL
9、L ); 100: 101: cl_mem clbuf2 = clCreateBuffer(context, 102: CL_MEM_READ_ONLY , 103: NWITEMS*sizeof(cl_float),NULL, 104: 105: 106: status = clEnqueueWriteBuffer(queue, clbuf2, 1, 107: 0, NWITEMS*sizeof(cl_float), buf2, 0, 0, 0); 108: 109: cl_mem buffer = clCreateBuffer( context, 110: CL_MEM_WRITE_ONL
10、Y, 111: NWITEMS * sizeof(cl_float), 112: NULL, NULL ); 113: 114: const char * filename = add.cl 115:string sourceStr; 116: status = convertToString(filename, sourceStr); 117: const char * source = sourceStr.c_str(); 118: size_t sourceSize = strlen(source) ; 119: 120: /创建程序对象 121: cl_program program
11、= clCreateProgramWithSource( 122: context, 123: 124:source, 125: sourceSize, 126: 127: /编译程序对象 128: status = clBuildProgram( program, 1, &device, NULL, NULL, NULL ); 129: if(status != 0) 130: 131:clBuild failed:%dn, status); 132: char tbuf0x10000; 133: clGetProgramBuildInfo(program, device, CL_PROGR
12、AM_BUILD_LOG, 0x10000, tbuf, NULL); 134:n%sn, tbuf); 135: return -1; 136: 137: 138: /创建Kernel对象 139: cl_kernel kernel = clCreateKernel( program, vecadd, NULL ); 140: /设置Kernel参数 141: cl_int clnum = NWITEMS; 142: clSetKernelArg(kernel, 0, sizeof(cl_mem), (void*) &clbuf1); 143: clSetKernelArg(kernel,
13、1, sizeof(cl_mem), (void*) &clbuf2); 144: clSetKernelArg(kernel, 2, sizeof(cl_mem), (void*) &buffer); 145: 146: /执行kernel 147: cl_event ev; 148: size_t global_work_size = NWITEMS; 149: clEnqueueNDRangeKernel( queue, 150: kernel, 151: 152: NULL, 153:global_work_size, 154: NULL, 0, NULL, &ev); 155: cl
14、Finish( queue ); 156: 157: /数据拷回host内存 158: cl_float *ptr; 159: ptr = (cl_float *) clEnqueueMapBuffer( queue, 160: buffer, 161: CL_TRUE, 162: CL_MAP_READ, 163: 0, 164: 165: 0, NULL, NULL, NULL ); 166: /结果验证,和cpu计算的结果比较 167:memcmp(buf, ptr, NWITEMS) 168:Verify passedn); 169: else printf(verify failed
15、 170: 171: if(buf) 172: free(buf); 173: if(buf1) 174: free(buf1); 175: if(buf2) 176: free(buf2); 177: 178: /删除OpenCL资源对象 179: clReleaseMemObject(clbuf1); 180: clReleaseMemObject(clbuf2); 181: clReleaseMemObject(buffer); 182: clReleaseProgram(program); 183: clReleaseCommandQueue(queue); 184: clReleaseContext(context); 185: 186: 187:也可以在
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