chundoong-lab-ta/SamsungDS22/submissions/HW2/jhyeon93.kim/mat_mul.cpp

58 lines
1.3 KiB
C++

#include "mat_mul.h"
#include <cstdlib>
#include <cstdio>
#include <pthread.h>
static float *A, *B, *C;
static int M, N, K;
static int num_threads;
static int slice;
static void* mat_mul_thread(void *data) {
//// TODO: parallelize & optimize matrix multiplication
int pid = * (int *) data;
int start = pid * slice;
int end = ( pid == num_threads - 1 ) ? M : (pid + 1) * slice;
int bs = 32;
for (int kk=0; kk < K; kk+=bs) {
int row_A = start * K;
int row_C = start * N;
for (int i= start; i < end; ++i) {
for (int k=kk; k < ((kk+bs < K)? kk+bs : K); ++k){
for (int j=0; j < N; ++j) {
C[row_C + j] += A[row_A + k] * B[k * N + j];
}
}
row_A += K; row_C += N;
}
}
return NULL;
}
void mat_mul(float *_A, float *_B, float *_C, int _M, int _N, int _K, int _num_threads) {
A = _A, B = _B, C = _C;
M = _M, N = _N, K = _K;
num_threads = _num_threads;
// TODO: create '_num_threads' pthreads
if (M < num_threads) num_threads = M;
slice = M / num_threads;
pthread_t* threads;
threads = (pthread_t*)malloc((num_threads) * sizeof(pthread_t));
for (int i=0; i < num_threads; ++i) {
int * pid = (int *) malloc(sizeof(int));
*pid = i;
pthread_create(&threads[i], NULL, mat_mul_thread, (void*)pid);
}
for(int i=0; i < num_threads; ++i)
pthread_join (threads[i], NULL);
}