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122 lines
3.6 KiB
Plaintext
122 lines
3.6 KiB
Plaintext
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#include "cuda_runtime.h"
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#include "device_launch_parameters.h"
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#include <stdio.h>
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cudaError_t addWithCuda(int *c, const int *a, const int *b, unsigned int size);
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__global__ void addKernel(int *c, const int *a, const int *b)
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{
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int i = threadIdx.x;
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c[i] = a[i] + b[i];
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}
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int main()
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{
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const int arraySize = 5;
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const int a[arraySize] = { 1, 2, 3, 4, 5 };
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const int b[arraySize] = { 10, 20, 30, 40, 50 };
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int c[arraySize] = { 0 };
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// Add vectors in parallel.
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cudaError_t cudaStatus = addWithCuda(c, a, b, arraySize);
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "addWithCuda failed!");
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return 1;
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}
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printf("{1,2,3,4,5} + {10,20,30,40,50} = {%d,%d,%d,%d,%d}\n",
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c[0], c[1], c[2], c[3], c[4]);
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// cudaDeviceReset must be called before exiting in order for profiling and
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// tracing tools such as Nsight and Visual Profiler to show complete traces.
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cudaStatus = cudaDeviceReset();
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "cudaDeviceReset failed!");
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return 1;
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}
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return 0;
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}
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// Helper function for using CUDA to add vectors in parallel.
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cudaError_t addWithCuda(int *c, const int *a, const int *b, unsigned int size)
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{
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int *dev_a = 0;
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int *dev_b = 0;
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int *dev_c = 0;
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cudaError_t cudaStatus;
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// Choose which GPU to run on, change this on a multi-GPU system.
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cudaStatus = cudaSetDevice(0);
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "cudaSetDevice failed! Do you have a CUDA-capable GPU installed?");
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goto Error;
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}
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// Allocate GPU buffers for three vectors (two input, one output) .
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cudaStatus = cudaMalloc((void**)&dev_c, size * sizeof(int));
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "cudaMalloc failed!");
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goto Error;
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}
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cudaStatus = cudaMalloc((void**)&dev_a, size * sizeof(int));
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "cudaMalloc failed!");
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goto Error;
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}
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cudaStatus = cudaMalloc((void**)&dev_b, size * sizeof(int));
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "cudaMalloc failed!");
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goto Error;
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}
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// Copy input vectors from host memory to GPU buffers.
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cudaStatus = cudaMemcpy(dev_a, a, size * sizeof(int), cudaMemcpyHostToDevice);
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "cudaMemcpy failed!");
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goto Error;
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}
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cudaStatus = cudaMemcpy(dev_b, b, size * sizeof(int), cudaMemcpyHostToDevice);
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "cudaMemcpy failed!");
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goto Error;
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}
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// Launch a kernel on the GPU with one thread for each element.
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addKernel<<<1, size>>>(dev_c, dev_a, dev_b);
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// Check for any errors launching the kernel
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cudaStatus = cudaGetLastError();
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "addKernel launch failed: %s\n", cudaGetErrorString(cudaStatus));
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goto Error;
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}
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// cudaDeviceSynchronize waits for the kernel to finish, and returns
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// any errors encountered during the launch.
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cudaStatus = cudaDeviceSynchronize();
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "cudaDeviceSynchronize returned error code %d after launching addKernel!\n", cudaStatus);
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goto Error;
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}
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// Copy output vector from GPU buffer to host memory.
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cudaStatus = cudaMemcpy(c, dev_c, size * sizeof(int), cudaMemcpyDeviceToHost);
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if (cudaStatus != cudaSuccess) {
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fprintf(stderr, "cudaMemcpy failed!");
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goto Error;
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}
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Error:
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cudaFree(dev_c);
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cudaFree(dev_a);
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cudaFree(dev_b);
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return cudaStatus;
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}
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