cuda c源代码-1

古城微笑少年丶 2022-03-17 07:38 218阅读 0赞

记录下学习cuda过程中的源代码，附有注释以便回顾学习。

#include <iostream>
    using namespace std;
    
    __global__ void add(int a, int b, int *c) {
    	*c = a + b;
    }
    
    int test1(void) { // 设备指针和生成设备内存
    	int c;
    	int *dev_c;
    	cudaMalloc((void**)&dev_c, sizeof(int));
    	add << <1, 1 >> > (1, 3, dev_c);
    	//printf("%d\n", *dev_c);
    	cudaMemcpy(&c, dev_c, sizeof(int), cudaMemcpyDeviceToHost);
    	printf("%d\n", c);
    	cout << c << endl;
    	cudaFree(dev_c);
    	//test();
    	return 0;
    }
    
    int test2() { // 测试在主机代码使用设备指针
    	int *dev;
    	cudaMalloc((void**)&dev, sizeof(int));
    	*dev = 3; // 不能这样，虽然编译不会出现问题，但是运行过程中会中途退出
    	cout << "hello" << endl;
    	//cout << dev << endl;
    	return 0;
    }
    
    int test3() { // 获取设备信息
    	int count;
    	cudaGetDeviceCount(&count); // GPU数量
    	cout << "有" << count << "个GPU设备" << endl;
    	cudaDeviceProp prop;
    	for (int i = 0; i < count; ++i) {
    		cudaGetDeviceProperties(&prop, i);
    		cout << "  ---  Genenal Information of Device  --  " << endl;
    		cout << "name: " << prop.name << endl;
    		cout << "Compute capability: " << prop.major << "." << prop.minor << endl;
    		cout << "Clock Rate: " << prop.clockRate << endl;
    
    		cout << "\n  __  Memory Information for device __  " << endl;
    		cout << "Total global memery: " << prop.totalGlobalMem << endl;
    		cout << "Total constant memery: " << prop.totalConstMem << endl;// 常量内存总量，什么鬼
    	}
    	return 0;
    }
    
    void test4() { // 根据条件选择设备，版本号大于等于1.3
    	cudaDeviceProp prop;
    	int dev;
    	cudaGetDevice(&dev);
    	cout << "ID of current device is " << dev << endl;
    
    	memset(&prop, 0, sizeof(cudaDeviceProp));
    	prop.major = 1;
    	prop.minor = 3;
    	cudaChooseDevice(&dev, &prop);
    	cout << "the id of choose device is " << dev << endl;
    	cudaSetDevice(dev);
    }
    
    const int N = 10;
    
    __global__ void add(int *a, int *b, int *c) {
    	int tid = blockIdx.x;
    	if (tid < N) {
    		c[tid] = a[tid] + b[tid];
    	}
    }
    
    void test5() { // cuda进行十位的矢量相加
    	int a[N], b[N], c[N];
    	for (int i = 0; i < 10; ++i) { // 初始化矢量
    		a[i] = -i - 3;
    		b[i] = i * i;
    	}
    	int *dev_a, *dev_b, *dev_c; // 在GPU上分配内存
    	cudaMalloc((void**)&dev_a, N*sizeof(int));
    	cudaMalloc((void**)&dev_b, N * sizeof(int));
    	cudaMalloc((void**)&dev_c, N * sizeof(int));
    	cudaMemcpy(dev_a, a, sizeof(a), cudaMemcpyHostToDevice);
    	cudaMemcpy(dev_b, b, sizeof(b), cudaMemcpyHostToDevice);
    	for (int i = 0; i < 100000; ++i)
    		add << <N, 1 >> > (dev_a, dev_b, dev_c); // 左线程块的数量，右一个线程块的线程数量
    	cudaMemcpy(c, dev_c, sizeof(c), cudaMemcpyDeviceToHost);
    
    	for (int i = 0; i < N; ++i) {
    		cout << a[i] << " + " << b[i] << " = " << c[i] << endl;
    	}
    
    	cudaFree(dev_a);
    	cudaFree(dev_b);
    	cudaFree(dev_c);
    }
    
    __global__ void add_2(int *a, int *b, int *c) {
    	int tid = threadIdx.x;
    	if (tid < N) {
    		c[tid] = a[tid] + b[tid];
    	}
    }
    
    void test6() { // cuda进行十位的矢量相加 // 使用并行线程而非并行线程块实现
    	int a[N], b[N], c[N];
    	for (int i = 0; i < 10; ++i) { // 初始化矢量
    		a[i] = -i - 3;
    		b[i] = i * i;
    	}
    	int *dev_a, *dev_b, *dev_c; // 在GPU上分配内存
    	cudaMalloc((void**)&dev_a, N * sizeof(int));
    	cudaMalloc((void**)&dev_b, N * sizeof(int));
    	cudaMalloc((void**)&dev_c, N * sizeof(int));
    	cudaMemcpy(dev_a, a, sizeof(a), cudaMemcpyHostToDevice);
    	cudaMemcpy(dev_b, b, sizeof(b), cudaMemcpyHostToDevice);
    	for (int i = 0; i < 100000; ++i)
    		add_2 << <1, N >> > (dev_a, dev_b, dev_c); // 左线程块的数量，右一个线程块的线程数量
    	cudaMemcpy(c, dev_c, sizeof(c), cudaMemcpyDeviceToHost);
    
    	for (int i = 0; i < N; ++i) {
    		cout << a[i] << " + " << b[i] << " = " << c[i] << endl;
    	}
    
    	cudaFree(dev_a);
    	cudaFree(dev_b);
    	cudaFree(dev_c);
    }
    
    __global__ void add_3() {
    	int bx = blockIdx.x, tx = threadIdx.x;
    	int bd = blockDim.x, gd = gridDim.x; // 测试有多少个
    	printf("bx = %d  tx = %d  bd = %d  gd = %d\n\n", bx, tx, bd, gd);
    	//cout << "hello, world" << endl; // 核函数里面似乎不能使用cout？可以使用printf？
    	//cout << "bx = " << bx << "  tx = " << tx << endl;
    	//cout << "bd = " << bd << "  gd = " << gridDim.x << endl << endl;
    }
    
    void test7() {
    	add_3 << <2, 5 >> > ();
    }
    
    int main() {
    	test7();
    }