time.c revision 5ec10eaad3b09875b91e19a20bbdfa06f2117562 
1#include <time.h>
2#include <sys/time.h>
3
4#include "fio.h"
5
6static struct timeval genesis;
7static unsigned long ns_granularity;
8
9unsigned long long utime_since(struct timeval *s, struct timeval *e)
10{
11	long sec, usec;
12	unsigned long long ret;
13
14	sec = e->tv_sec - s->tv_sec;
15	usec = e->tv_usec - s->tv_usec;
16	if (sec > 0 && usec < 0) {
17		sec--;
18		usec += 1000000;
19	}
20
21	/*
22	 * time warp bug on some kernels?
23	 */
24	if (sec < 0 || (sec == 0 && usec < 0))
25		return 0;
26
27	ret = sec * 1000000ULL + usec;
28
29	return ret;
30}
31
32unsigned long long utime_since_now(struct timeval *s)
33{
34	struct timeval t;
35
36	fio_gettime(&t, NULL);
37	return utime_since(s, &t);
38}
39
40unsigned long mtime_since(struct timeval *s, struct timeval *e)
41{
42	long sec, usec, ret;
43
44	sec = e->tv_sec - s->tv_sec;
45	usec = e->tv_usec - s->tv_usec;
46	if (sec > 0 && usec < 0) {
47		sec--;
48		usec += 1000000;
49	}
50
51	sec *= 1000UL;
52	usec /= 1000UL;
53	ret = sec + usec;
54
55	/*
56	 * time warp bug on some kernels?
57	 */
58	if (ret < 0)
59		ret = 0;
60
61	return ret;
62}
63
64unsigned long mtime_since_now(struct timeval *s)
65{
66	struct timeval t;
67	void *p = __builtin_return_address(0);
68
69	fio_gettime(&t, p);
70	return mtime_since(s, &t);
71}
72
73unsigned long time_since_now(struct timeval *s)
74{
75	return mtime_since_now(s) / 1000;
76}
77
78/*
79 * busy looping version for the last few usec
80 */
81void __usec_sleep(unsigned int usec)
82{
83	struct timeval start;
84
85	fio_gettime(&start, NULL);
86	while (utime_since_now(&start) < usec)
87		nop;
88}
89
90void usec_sleep(struct thread_data *td, unsigned long usec)
91{
92	struct timespec req;
93	struct timeval tv;
94
95	do {
96		unsigned long ts = usec;
97
98		if (usec < ns_granularity) {
99			__usec_sleep(usec);
100			break;
101		}
102
103		ts = usec - ns_granularity;
104
105		if (ts >= 1000000) {
106			req.tv_sec = ts / 1000000;
107			ts -= 1000000 * req.tv_sec;
108		} else
109			req.tv_sec = 0;
110
111		req.tv_nsec = ts * 1000;
112		fio_gettime(&tv, NULL);
113
114		if (nanosleep(&req, NULL) < 0)
115			break;
116
117		ts = utime_since_now(&tv);
118		if (ts >= usec)
119			break;
120
121		usec -= ts;
122	} while (!td->terminate);
123}
124
125void rate_throttle(struct thread_data *td, unsigned long time_spent,
126		   unsigned int bytes)
127{
128	unsigned long usec_cycle;
129	unsigned int bs;
130
131	if (!td->o.rate && !td->o.rate_iops)
132		return;
133
134	if (td_rw(td))
135		bs = td->o.rw_min_bs;
136	else if (td_read(td))
137		bs = td->o.min_bs[DDIR_READ];
138	else
139		bs = td->o.min_bs[DDIR_WRITE];
140
141	usec_cycle = td->rate_usec_cycle * (bytes / bs);
142
143	if (time_spent < usec_cycle) {
144		unsigned long s = usec_cycle - time_spent;
145
146		td->rate_pending_usleep += s;
147
148		if (td->rate_pending_usleep >= 100000) {
149			struct timeval t;
150
151			fio_gettime(&t, NULL);
152			usec_sleep(td, td->rate_pending_usleep);
153			td->rate_pending_usleep -= utime_since_now(&t);
154		}
155	} else {
156		long overtime = time_spent - usec_cycle;
157
158		td->rate_pending_usleep -= overtime;
159	}
160}
161
162unsigned long mtime_since_genesis(void)
163{
164	return mtime_since_now(&genesis);
165}
166
167static void fio_init time_init(void)
168{
169	int i;
170
171	/*
172	 * Check the granularity of the nanosleep function
173	 */
174	for (i = 0; i < 10; i++) {
175		struct timeval tv;
176		struct timespec ts;
177		unsigned long elapsed;
178
179		fio_gettime(&tv, NULL);
180		ts.tv_sec = 0;
181		ts.tv_nsec = 1000;
182
183		nanosleep(&ts, NULL);
184		elapsed = utime_since_now(&tv);
185
186		if (elapsed > ns_granularity)
187			ns_granularity = elapsed;
188	}
189}
190
191void set_genesis_time(void)
192{
193	fio_gettime(&genesis, NULL);
194}
195
196void fill_start_time(struct timeval *t)
197{
198	memcpy(t, &genesis, sizeof(genesis));
199}
200