74 lines
1.4 KiB
C
74 lines
1.4 KiB
C
|
#include <assert.h>
|
||
|
|
#include <pthread.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <time.h>
|
||
|
|
|
||
|
|
static inline double tstamp(void)
|
||
|
|
{
|
||
|
|
struct timespec tv;
|
||
|
|
clock_gettime(CLOCK_REALTIME, &tv);
|
||
|
|
return tv.tv_sec + tv.tv_nsec * 1.0e-9;
|
||
|
|
}
|
||
|
|
|
||
|
|
typedef struct thread_arg
|
||
|
|
{
|
||
|
|
long int start;
|
||
|
|
long int limit;
|
||
|
|
long int inc;
|
||
|
|
long int S;
|
||
|
|
} thread_arg;
|
||
|
|
|
||
|
|
void *slice(void *arg)
|
||
|
|
{
|
||
|
|
thread_arg *a = (thread_arg *)arg;
|
||
|
|
long int S = 0;
|
||
|
|
|
||
|
|
for (long int i = a->start; i <= a->limit; i = i + a->inc)
|
||
|
|
{
|
||
|
|
S += i;
|
||
|
|
}
|
||
|
|
a->S = S;
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
int main(int argc, char *argv[])
|
||
|
|
{
|
||
|
|
long int N, M, S = 0;
|
||
|
|
double t1, t2;
|
||
|
|
thread_arg *args;
|
||
|
|
pthread_t *ths;
|
||
|
|
|
||
|
|
assert(argc >= 3);
|
||
|
|
N = strtol(argv[1], NULL, 0);
|
||
|
|
M = strtol(argv[2], NULL, 0);
|
||
|
|
t1 = tstamp();
|
||
|
|
|
||
|
|
args = (thread_arg *)calloc(M, sizeof(thread_arg));
|
||
|
|
assert(args != NULL);
|
||
|
|
|
||
|
|
ths = (pthread_t *)calloc(M, sizeof(pthread_t));
|
||
|
|
assert(ths != NULL);
|
||
|
|
|
||
|
|
for (int i = 0; i < M; i++)
|
||
|
|
{
|
||
|
|
args[i].inc = M;
|
||
|
|
args[i].limit = N;
|
||
|
|
args[i].start = i + 1;
|
||
|
|
pthread_create(ths + i, NULL, slice, (void *)(args + i));
|
||
|
|
}
|
||
|
|
|
||
|
|
for (int i = 0; i < M; i++)
|
||
|
|
{
|
||
|
|
pthread_join(ths[i], NULL);
|
||
|
|
S += args[i].S;
|
||
|
|
}
|
||
|
|
|
||
|
|
assert(S == N * (N + 1) / 2);
|
||
|
|
|
||
|
|
t2 = tstamp();
|
||
|
|
printf("S = %ld\n", S);
|
||
|
|
printf("t = %lf\n", t2 - t1);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|