Add gettime.h
[fio.git] / gettime.c
CommitLineData
02bcaa8c 1/*
f5cc024a 2 * Clock functions
02bcaa8c 3 */
f5cc024a 4
02bcaa8c 5#include <unistd.h>
c223da83 6#include <math.h>
02bcaa8c 7#include <sys/time.h>
03e20d68 8#include <time.h>
02bcaa8c
JA
9
10#include "fio.h"
be4ecfdf 11#include "smalloc.h"
02bcaa8c
JA
12
13#include "hash.h"
14
09a32402 15#ifdef ARCH_HAVE_CPU_CLOCK
c223da83 16static unsigned long cycles_per_usec;
c223da83 17static unsigned long last_cycles;
09a32402
JA
18#endif
19static struct timeval last_tv;
3e488920 20static int last_tv_valid;
02bcaa8c 21
be4ecfdf
JA
22static struct timeval *fio_tv;
23int fio_gtod_offload = 0;
24int fio_gtod_cpu = -1;
783a3eb1 25static pthread_t gtod_thread;
be4ecfdf 26
c223da83
JA
27enum fio_cs fio_clock_source = CS_GTOD;
28
02bcaa8c
JA
29#ifdef FIO_DEBUG_TIME
30
31#define HASH_BITS 8
32#define HASH_SIZE (1 << HASH_BITS)
33
01743ee1 34static struct flist_head hash[HASH_SIZE];
02bcaa8c
JA
35static int gtod_inited;
36
37struct gtod_log {
01743ee1 38 struct flist_head list;
02bcaa8c
JA
39 void *caller;
40 unsigned long calls;
41};
42
43static struct gtod_log *find_hash(void *caller)
44{
45 unsigned long h = hash_ptr(caller, HASH_BITS);
01743ee1 46 struct flist_head *entry;
02bcaa8c 47
01743ee1
JA
48 flist_for_each(entry, &hash[h]) {
49 struct gtod_log *log = flist_entry(entry, struct gtod_log,
50 list);
02bcaa8c
JA
51
52 if (log->caller == caller)
53 return log;
54 }
55
56 return NULL;
57}
58
59static struct gtod_log *find_log(void *caller)
60{
61 struct gtod_log *log = find_hash(caller);
62
63 if (!log) {
64 unsigned long h;
65
66 log = malloc(sizeof(*log));
01743ee1 67 INIT_FLIST_HEAD(&log->list);
02bcaa8c
JA
68 log->caller = caller;
69 log->calls = 0;
70
71 h = hash_ptr(caller, HASH_BITS);
01743ee1 72 flist_add_tail(&log->list, &hash[h]);
02bcaa8c
JA
73 }
74
75 return log;
76}
77
78static void gtod_log_caller(void *caller)
79{
80 if (gtod_inited) {
81 struct gtod_log *log = find_log(caller);
82
83 log->calls++;
84 }
85}
86
87static void fio_exit fio_dump_gtod(void)
88{
89 unsigned long total_calls = 0;
90 int i;
91
92 for (i = 0; i < HASH_SIZE; i++) {
01743ee1 93 struct flist_head *entry;
02bcaa8c
JA
94 struct gtod_log *log;
95
01743ee1
JA
96 flist_for_each(entry, &hash[i]) {
97 log = flist_entry(entry, struct gtod_log, list);
02bcaa8c 98
5ec10eaa
JA
99 printf("function %p, calls %lu\n", log->caller,
100 log->calls);
02bcaa8c
JA
101 total_calls += log->calls;
102 }
103 }
104
105 printf("Total %lu gettimeofday\n", total_calls);
106}
107
108static void fio_init gtod_init(void)
109{
110 int i;
111
112 for (i = 0; i < HASH_SIZE; i++)
01743ee1 113 INIT_FLIST_HEAD(&hash[i]);
02bcaa8c
JA
114
115 gtod_inited = 1;
116}
117
118#endif /* FIO_DEBUG_TIME */
119
1e97cce9 120#ifdef FIO_DEBUG_TIME
02bcaa8c 121void fio_gettime(struct timeval *tp, void *caller)
1e97cce9
JA
122#else
123void fio_gettime(struct timeval *tp, void fio_unused *caller)
124#endif
02bcaa8c
JA
125{
126#ifdef FIO_DEBUG_TIME
127 if (!caller)
128 caller = __builtin_return_address(0);
129
130 gtod_log_caller(caller);
02bcaa8c 131#endif
be4ecfdf
JA
132 if (fio_tv) {
133 memcpy(tp, fio_tv, sizeof(*tp));
134 return;
c223da83
JA
135 }
136
137 switch (fio_clock_source) {
138 case CS_GTOD:
02bcaa8c 139 gettimeofday(tp, NULL);
c223da83
JA
140 break;
141 case CS_CGETTIME: {
02bcaa8c
JA
142 struct timespec ts;
143
5bd9c78c
JA
144#ifdef FIO_HAVE_CLOCK_MONOTONIC
145 if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
146#else
d481e006 147 if (clock_gettime(CLOCK_REALTIME, &ts) < 0) {
5bd9c78c 148#endif
c223da83
JA
149 log_err("fio: clock_gettime fails\n");
150 assert(0);
02bcaa8c
JA
151 }
152
153 tp->tv_sec = ts.tv_sec;
154 tp->tv_usec = ts.tv_nsec / 1000;
c223da83
JA
155 break;
156 }
157#ifdef ARCH_HAVE_CPU_CLOCK
158 case CS_CPUCLOCK: {
159 unsigned long long usecs, t;
160
161 t = get_cpu_clock();
162 if (t < last_cycles) {
163 dprint(FD_TIME, "CPU clock going back in time\n");
164 t = last_cycles;
165 }
166
167 usecs = t / cycles_per_usec;
168 tp->tv_sec = usecs / 1000000;
169 tp->tv_usec = usecs % 1000000;
170 last_cycles = t;
171 break;
172 }
173#endif
174 default:
175 log_err("fio: invalid clock source %d\n", fio_clock_source);
176 break;
02bcaa8c 177 }
3e488920
JA
178
179 /*
180 * If Linux is using the tsc clock on non-synced processors,
181 * sometimes time can appear to drift backwards. Fix that up.
182 */
183 if (last_tv_valid) {
184 if (tp->tv_sec < last_tv.tv_sec)
185 tp->tv_sec = last_tv.tv_sec;
186 else if (last_tv.tv_sec == tp->tv_sec &&
187 tp->tv_usec < last_tv.tv_usec)
188 tp->tv_usec = last_tv.tv_usec;
189 }
190 last_tv_valid = 1;
191 memcpy(&last_tv, tp, sizeof(*tp));
02bcaa8c 192}
be4ecfdf 193
09a32402 194#ifdef ARCH_HAVE_CPU_CLOCK
c223da83
JA
195static unsigned long get_cycles_per_usec(void)
196{
197 struct timeval s, e;
198 unsigned long long c_s, c_e;
199
200 gettimeofday(&s, NULL);
201 c_s = get_cpu_clock();
202 do {
203 unsigned long long elapsed;
204
205 gettimeofday(&e, NULL);
206 elapsed = utime_since(&s, &e);
207 if (elapsed >= 10) {
208 c_e = get_cpu_clock();
209 break;
210 }
211 } while (1);
212
213 return c_e - c_s;
214}
215
09a32402 216static void calibrate_cpu_clock(void)
c223da83
JA
217{
218 double delta, mean, S;
219 unsigned long avg, cycles[10];
220 int i, samples;
221
c223da83
JA
222 cycles[0] = get_cycles_per_usec();
223 S = delta = mean = 0.0;
224 for (i = 0; i < 10; i++) {
225 cycles[i] = get_cycles_per_usec();
226 delta = cycles[i] - mean;
227 if (delta) {
228 mean += delta / (i + 1.0);
229 S += delta * (cycles[i] - mean);
230 }
231 }
232
233 S = sqrt(S / (10 - 1.0));
234
235 samples = avg = 0;
236 for (i = 0; i < 10; i++) {
237 double this = cycles[i];
238
03e20d68 239 if ((fmax(this, mean) - fmin(this, mean)) > S)
c223da83
JA
240 continue;
241 samples++;
242 avg += this;
243 }
244
245 S /= 10.0;
246 mean /= 10.0;
247
248 for (i = 0; i < 10; i++)
249 dprint(FD_TIME, "cycles[%d]=%lu\n", i, cycles[i] / 10);
250
251 avg /= (samples * 10);
252 dprint(FD_TIME, "avg: %lu\n", avg);
253 dprint(FD_TIME, "mean=%f, S=%f\n", mean, S);
254
255 cycles_per_usec = avg;
09a32402
JA
256
257}
258#else
259static void calibrate_cpu_clock(void)
260{
261}
262#endif
263
264void fio_clock_init(void)
265{
266 last_tv_valid = 0;
267 calibrate_cpu_clock();
c223da83
JA
268}
269
be4ecfdf
JA
270void fio_gtod_init(void)
271{
272 fio_tv = smalloc(sizeof(struct timeval));
273 assert(fio_tv);
274}
275
a7346816 276static void fio_gtod_update(void)
be4ecfdf
JA
277{
278 gettimeofday(fio_tv, NULL);
279}
783a3eb1
JA
280
281static void *gtod_thread_main(void *data)
282{
283 struct fio_mutex *mutex = data;
284
285 fio_mutex_up(mutex);
286
287 /*
288 * As long as we have jobs around, update the clock. It would be nice
289 * to have some way of NOT hammering that CPU with gettimeofday(),
290 * but I'm not sure what to use outside of a simple CPU nop to relax
291 * it - we don't want to lose precision.
292 */
293 while (threads) {
294 fio_gtod_update();
295 nop;
296 }
297
298 return NULL;
299}
300
301int fio_start_gtod_thread(void)
302{
303 struct fio_mutex *mutex;
304 pthread_attr_t attr;
305 int ret;
306
307 mutex = fio_mutex_init(0);
308 if (!mutex)
309 return 1;
310
311 pthread_attr_init(&attr);
312 pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN);
313 ret = pthread_create(&gtod_thread, &attr, gtod_thread_main, NULL);
314 pthread_attr_destroy(&attr);
315 if (ret) {
316 log_err("Can't create gtod thread: %s\n", strerror(ret));
317 goto err;
318 }
319
320 ret = pthread_detach(gtod_thread);
321 if (ret) {
322 log_err("Can't detatch gtod thread: %s\n", strerror(ret));
323 goto err;
324 }
325
326 dprint(FD_MUTEX, "wait on startup_mutex\n");
327 fio_mutex_down(mutex);
328 dprint(FD_MUTEX, "done waiting on startup_mutex\n");
329err:
330 fio_mutex_remove(mutex);
331 return ret;
332}