读书笔记-OpenCL编程指南 HelloWorld

ゝ一纸荒年。 2023-02-22 13:39 33阅读 0赞

main函数会实现或调用一组函数，完成以下操作：  
![在这里插入图片描述][20200703224731633.png]

可以和[OpenCL入门二：OpenCL基础概念][OpenCL_OpenCL]中的代码进行对比

## OpenCL内核 ##

![在这里插入图片描述][20200703224839255.png]

__kernel void vector_add(global const float *a, global const float *b, global float *result)
    {  
     int gid = get_global_id(0);
     result[gid] = a[gid] + b[gid];
    }
    ————————————————
    版权声明：本文为CSDN博主「肥叔菌」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
    原文链接：https://blog.csdn.net/asmartkiller/article/details/86611145

## 主函数 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 3]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 4]

### 选择OpenCL平台并创建一个上下文 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 5]  
![在这里插入图片描述][20200703231428951.png]

### 选择设备并创建命令队列 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 6]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 7]

### 创建和构建程序对象 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 8]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 9]

### 执行内核 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 10]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 11]

cl_context context = 0;
    cl_command_queue commandQueue = 0;
    cl_program program = 0;
    cl_device_id device = 0;
    cl_kernel kernel = 0;
    cl_mem memObjects[3] = {  0, 0, 0};
    cl_int errNum;
    
    // 创建OpenCL上下文
    context = CreateContext(&device);
    //获得OpenCL设备，并创建命令队列
    commandQueue = CreateCommandQueue(context, device);
    // 创建OpenCL程序
    program = CreateProgram(context, device, "device.cl");
    // 创建OpenCL内核
    kernel = clCreateKernel(program, "vector_add", NULL);
    // 创建OpenCL内存对象
    float result[ARRAY_SIZE];
    float a[ARRAY_SIZE];
    float b[ARRAY_SIZE];
    for (int i = 0; i < ARRAY_SIZE; i++)
    { 
    	a[i] = (float)i;
    	b[i] = (float)(i * 2);
    } 
    if (!CreateMemObjects(context, memObjects, a, b))
    { 
    	return 1;
    }
    // 设置内核参数
    errNum = clSetKernelArg(kernel, 0, sizeof(cl_mem), &memObjects[0]);
    errNum |= clSetKernelArg(kernel, 1, sizeof(cl_mem), &memObjects[1]);
    errNum |= clSetKernelArg(kernel, 2, sizeof(cl_mem), &memObjects[2]);
    if (errNum != CL_SUCCESS)
    { 
    	return 1;
    }
    // 执行内核
    size_t gloabalWorkSize = ARRAY_SIZE;
     size_t localWorkSize = 1;
     std::cout << "GPU 运行开始:" << time_stamp() << std::endl;
     errNum = clEnqueueNDRangeKernel(commandQueue, kernel, 1, NULL, &gloabalWorkSize, &localWorkSize, 0, NULL, NULL);
     std::cout << "GPU 运行结束:" << time_stamp() << std::endl;
    //计算结果拷贝回主机
    errNum = clEnqueueReadBuffer(commandQueue, memObjects[2], CL_TRUE, 0, sizeof(float) * ARRAY_SIZE, result, 0, NULL, NULL);
    for (int i = 0; i < ARRAY_SIZE; i++)
     { 
      printf("i = %d:%f\n",i,result[i]);
     }
    ————————————————
    版权声明：本文为CSDN博主「肥叔菌」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
    原文链接：https://blog.csdn.net/asmartkiller/article/details/86611145

## 检查OpenCL中的错误 ##

![在这里插入图片描述][20200703232720107.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 12]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 13]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FzbWFydGtpbGxlcg_size_16_color_FFFFFF_t_70 14]

[20200703224731633.png]: https://img-blog.csdnimg.cn/20200703224731633.png
[OpenCL_OpenCL]: https://blog.csdn.net/asmartkiller/article/details/86611145
[20200703224839255.png]: https://img-blog.csdnimg.cn/20200703224839255.png
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