chundoong-lab-ta/SHPC2022/hw2_answer/matmul/matmul.c

69 lines
1.6 KiB
C

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
struct thread_arg {
const float *A;
const float *B;
float *C;
int M;
int N;
int K;
int num_threads;
int rank; /* id of this thread */
} args[256];
static pthread_t threads[256];
static void* matmul_kernel(void *arg) {
struct thread_arg *_arg = (struct thread_arg*) arg;
const float *A = _arg->A;
const float *B = _arg->B;
float *C = _arg->C;
int M = _arg->M;
int N = _arg->N;
int K = _arg->K;
int num_threads = _arg-> num_threads;
int rank = _arg->rank;
int start = ((M + num_threads-1) / num_threads) * rank;
int end = ((M + num_threads-1) / num_threads) * (rank+1);
if (end >= M) end = M;
for (int i = start; i < end; ++i) {
for (int k = 0; k < K; ++k) {
for (int j = 0; j < N; ++j) {
C[i * N + j] += A[i * K + k] * B[k * N + j];
}
}
}
return NULL;
}
void matmul(const float *A, const float *B, float *C, int M, int N, int K, int num_threads) {
int err;
for (int t = 0; t < num_threads; ++t) {
args[t].A = A;
args[t].B = B;
args[t].C = C;
args[t].M = M;
args[t].N = N;
args[t].K = K;
args[t].num_threads = num_threads;
args[t].rank = t;
err = pthread_create(&threads[t], NULL, matmul_kernel, (void*)&args[t]);
if (err) {
printf("pthread_create(%d) failed with err %d\n", t, err);
exit(EXIT_FAILURE);
}
}
for (int t = 0; t < num_threads; ++t) {
err = pthread_join(threads[t], NULL);
if (err) {
printf("pthread_join(%d) failed with err %d\n", t, err);
exit(EXIT_FAILURE);
}
}
}