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| 1 | +// dot_product.cu |
| 2 | +#include <cuda_runtime.h> |
| 3 | +#include <stdio.h> |
| 4 | + |
| 5 | +extern "C" { |
| 6 | + |
| 7 | +// Kernel CUDA para multiplicar os vetores |
| 8 | +__global__ void dot_product_kernel(const double* x, const double* y, double* partial_sum, int n) { |
| 9 | + __shared__ double cache[256]; // Cache compartilhado para redução |
| 10 | + int tid = threadIdx.x + blockIdx.x * blockDim.x; |
| 11 | + int cacheIndex = threadIdx.x; |
| 12 | + |
| 13 | + double temp = 0.0; |
| 14 | + while (tid < n) { |
| 15 | + temp += x[tid] * y[tid]; |
| 16 | + tid += blockDim.x * gridDim.x; |
| 17 | + } |
| 18 | + |
| 19 | + cache[cacheIndex] = temp; |
| 20 | + |
| 21 | + __syncthreads(); |
| 22 | + |
| 23 | + // Redução paralela |
| 24 | + int i = blockDim.x/2; |
| 25 | + while (i != 0) { |
| 26 | + if (cacheIndex < i) { |
| 27 | + cache[cacheIndex] += cache[cacheIndex + i]; |
| 28 | + } |
| 29 | + __syncthreads(); |
| 30 | + i /= 2; |
| 31 | + } |
| 32 | + |
| 33 | + if (cacheIndex == 0) |
| 34 | + partial_sum[blockIdx.x] = cache[0]; |
| 35 | +} |
| 36 | + |
| 37 | +// Função wrapper para ser chamada do Rust |
| 38 | +void dot_product_gpu(const double* x, const double* y, double* result, int n) { |
| 39 | + double *d_x, *d_y, *d_partial_sum; |
| 40 | + int blocks = 32; |
| 41 | + int threads = 256; |
| 42 | + |
| 43 | + cudaMalloc((void**)&d_x, n * sizeof(double)); |
| 44 | + cudaMalloc((void**)&d_y, n * sizeof(double)); |
| 45 | + cudaMalloc((void**)&d_partial_sum, blocks * sizeof(double)); |
| 46 | + |
| 47 | + cudaMemcpy(d_x, x, n * sizeof(double), cudaMemcpyHostToDevice); |
| 48 | + cudaMemcpy(d_y, y, n * sizeof(double), cudaMemcpyHostToDevice); |
| 49 | + |
| 50 | + dot_product_kernel<<<blocks, threads>>>(d_x, d_y, d_partial_sum, n); |
| 51 | + |
| 52 | + double* h_partial_sum = (double*) malloc(blocks * sizeof(double)); |
| 53 | + cudaMemcpy(h_partial_sum, d_partial_sum, blocks * sizeof(double), cudaMemcpyDeviceToHost); |
| 54 | + |
| 55 | + *result = 0.0; |
| 56 | + for (int i = 0; i < blocks; i++) { |
| 57 | + *result += h_partial_sum[i]; |
| 58 | + } |
| 59 | + |
| 60 | + free(h_partial_sum); |
| 61 | + cudaFree(d_x); |
| 62 | + cudaFree(d_y); |
| 63 | + cudaFree(d_partial_sum); |
| 64 | +} |
| 65 | + |
| 66 | +} |
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