1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
#include <stdio.h>
#include <assert.h>
#include <sys/time.h>
#ifdef PTEST_USE_THREAD
# include <pthread.h>
# include <semaphore.h>
static sem_t done;
#endif
extern int add1(int, int);
static double time_delta(struct timeval *stop, struct timeval *start)
{
return (stop->tv_sec - start->tv_sec) +
1e-6 * (stop->tv_usec - start->tv_usec);
}
static double measure(void)
{
long long i, iterations;
int result;
struct timeval start, stop;
double elapsed;
add1(0, 0); /* prepare off-line */
i = 0;
iterations = 1000;
result = gettimeofday(&start, NULL);
assert(result == 0);
while (1) {
for (; i < iterations; i++) {
add1(((int)i) & 0xaaaaaa, ((int)i) & 0x555555);
}
result = gettimeofday(&stop, NULL);
assert(result == 0);
elapsed = time_delta(&stop, &start);
assert(elapsed >= 0.0);
if (elapsed > 2.5)
break;
iterations = iterations * 3 / 2;
}
return elapsed / (double)iterations;
}
static void *start_routine(void *arg)
{
double t = measure();
printf("time per call: %.3g\n", t);
#ifdef PTEST_USE_THREAD
int status = sem_post(&done);
assert(status == 0);
#endif
return arg;
}
int main(void)
{
#ifndef PTEST_USE_THREAD
start_routine(0);
#else
pthread_t th;
int i, status = sem_init(&done, 0, 0);
assert(status == 0);
add1(0, 0); /* this is the main thread */
for (i = 0; i < PTEST_USE_THREAD; i++) {
status = pthread_create(&th, NULL, start_routine, NULL);
assert(status == 0);
}
for (i = 0; i < PTEST_USE_THREAD; i++) {
status = sem_wait(&done);
assert(status == 0);
}
#endif
return 0;
}
|
