chundoong-lab-ta/SamsungDS22/submissions/HW6/kaye.jeong/mat_mul.cu

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#include "mat_mul.h"
#include <cstdio>
#include <cuda_runtime.h>
#define CUDA_CALL(f) \
{ \
cudaError_t err = (f); \
if (err != cudaSuccess) { \
fprintf(stderr, "CUDA error at [%s:%d] %d %s\n", __FILE__, __LINE__, \
err, cudaGetErrorString(err)); \
exit(1); \
} \
}
#define TILE_WIDTH 16
#define TS 32 // The square-root of the 2D tile-size (== work-group dims)
#define WPT 8 // The amount of work-per-thread, i.e. the thread-coarsening factor
#define RTS (TS/WPT) // The reduced tile-size in one dimension
#define MAX_NUM_GPU 4
int num_devices = 0;
__global__ void sgemm(float *A, float *B, float *C, int M, int N, int K) {
__shared__ float sm_M[TILE_WIDTH][TILE_WIDTH];
__shared__ float sm_N[TILE_WIDTH][TILE_WIDTH];
int blockx = blockIdx.x, blocky = blockIdx.y,
threadx = threadIdx.x, thready = threadIdx.y,
Row = blocky * TILE_WIDTH + thready,
Col = blockx * TILE_WIDTH + threadx;
float Pval = 0;
for (int m = 0; m < (K-1)/TILE_WIDTH+1; ++m) {
if (Row < M && m*TILE_WIDTH+threadx < K)
sm_M[thready][threadx] = A[Row*K + m*TILE_WIDTH+threadx];
else
sm_M[thready][threadx] = 0;
if (Col < N && m*TILE_WIDTH+thready < K)
sm_N[thready][threadx] = B[(m*TILE_WIDTH+thready)*N+Col];
else
sm_N[thready][threadx] = 0;
__syncthreads();
for (int k = 0; k < TILE_WIDTH; ++k)
Pval += sm_M[thready][k] * sm_N[k][threadx];
__syncthreads();
}
if (Row < M && Col < N)
C[Row*N+Col] = Pval;
}
// Array of device (GPU) pointers
static float *a_d[MAX_NUM_GPU];
static float *b_d[MAX_NUM_GPU];
static float *c_d[MAX_NUM_GPU];
static int M, N, K;
static int Mbegin[MAX_NUM_GPU], Mend[MAX_NUM_GPU];
void mat_mul(float *_A, float *_B, float *_C, int _M, int _N, int _K) {
// Launch kernel on every GPU
for (int i = 0; i < num_devices; i++) {
int MSize = Mend[i] - Mbegin[i];
dim3 gridDim((N-1)/TILE_WIDTH+1, (MSize-1)/TILE_WIDTH+1, 1);
dim3 blockDim(TILE_WIDTH, TILE_WIDTH, 1);
CUDA_CALL( cudaSetDevice(i) );
sgemm<<<gridDim, blockDim>>>(a_d[i], b_d[i], c_d[i], MSize , N, K);
}
// DO NOT REMOVE; NEEDED FOR TIME MEASURE
for (int i = 0; i < num_devices; i++) {
CUDA_CALL( cudaDeviceSynchronize() );
}
}
void mat_mul_init(float *A, float *B, float *C, int _M, int _N, int _K) {
M = _M, N = _N, K = _K;
CUDA_CALL( cudaGetDeviceCount(&num_devices) );
//num_devices = 1;
printf("Using %d devices\n", num_devices);
for (int i = 0; i < num_devices; i++) {
cudaDeviceProp prop;
CUDA_CALL( cudaGetDeviceProperties(&prop, i) );
// Try printing more detailed information here
printf("[GPU %d] %s\n", i, prop.name);
}
if (num_devices <= 0) {
printf("No CUDA device found. Aborting\n");
exit(1);
}
// Setup problem size for each GPU
for (int i = 0; i < num_devices; i++) {
Mbegin[i] = (M / num_devices) * i;
Mend[i] = (M / num_devices) * (i + 1);
}
Mend[num_devices - 1] = M;
// Allocate device memory for each GPU
for (int i = 0; i < num_devices; i++) {
CUDA_CALL( cudaSetDevice(i) );
CUDA_CALL( cudaMalloc(&a_d[i], (Mend[i] - Mbegin[i]) * K * sizeof(float)) );
CUDA_CALL( cudaMalloc(&b_d[i], K * N * sizeof(float)) );
CUDA_CALL( cudaMalloc(&c_d[i], (Mend[i] - Mbegin[i]) * N * sizeof(float)) );
}
// Upload A and B matrix to every GPU
for (int i = 0; i < num_devices; i++) {
CUDA_CALL( cudaMemcpy(a_d[i], A + Mbegin[i] * K,
(Mend[i] - Mbegin[i]) * K * sizeof(float),
cudaMemcpyHostToDevice) );
CUDA_CALL( cudaMemcpy(b_d[i], B, K * N * sizeof(float), cudaMemcpyHostToDevice) );
}
// DO NOT REMOVE; NEEDED FOR TIME MEASURE
for (int i = 0; i < num_devices; i++) {
CUDA_CALL( cudaDeviceSynchronize() );
}
}
void mat_mul_final(float *A, float *B, float *C, int M, int N, int K) {
// Do any post-matmul cleanup work here.
// Download C matrix from GPUs
for (int i = 0; i < num_devices; i++) {
CUDA_CALL( cudaMemcpy(C + Mbegin[i] * N, c_d[i],
(Mend[i] - Mbegin[i]) * N * sizeof(float),
cudaMemcpyDeviceToHost) );
}
// DO NOT REMOVE; NEEDED FOR TIME MEASURE
for (int i = 0; i < num_devices; i++) {
CUDA_CALL( cudaDeviceSynchronize() );
}
}