15 #ifdef ARCH_HAVE_CPU_CLOCK
16 static unsigned long cycles_per_usec;
17 static unsigned long last_cycles;
20 static struct timeval last_tv;
21 static int last_tv_valid;
23 enum fio_cs fio_clock_source = FIO_PREFERRED_CLOCK_SOURCE;
24 int fio_clock_source_set = 0;
25 enum fio_cs fio_clock_source_inited = CS_INVAL;
30 #define HASH_SIZE (1 << HASH_BITS)
32 static struct flist_head hash[HASH_SIZE];
33 static int gtod_inited;
36 struct flist_head list;
41 static struct gtod_log *find_hash(void *caller)
43 unsigned long h = hash_ptr(caller, HASH_BITS);
44 struct flist_head *entry;
46 flist_for_each(entry, &hash[h]) {
47 struct gtod_log *log = flist_entry(entry, struct gtod_log,
50 if (log->caller == caller)
57 static struct gtod_log *find_log(void *caller)
59 struct gtod_log *log = find_hash(caller);
64 log = malloc(sizeof(*log));
65 INIT_FLIST_HEAD(&log->list);
69 h = hash_ptr(caller, HASH_BITS);
70 flist_add_tail(&log->list, &hash[h]);
76 static void gtod_log_caller(void *caller)
79 struct gtod_log *log = find_log(caller);
85 static void fio_exit fio_dump_gtod(void)
87 unsigned long total_calls = 0;
90 for (i = 0; i < HASH_SIZE; i++) {
91 struct flist_head *entry;
94 flist_for_each(entry, &hash[i]) {
95 log = flist_entry(entry, struct gtod_log, list);
97 printf("function %p, calls %lu\n", log->caller,
99 total_calls += log->calls;
103 printf("Total %lu gettimeofday\n", total_calls);
106 static void fio_init gtod_init(void)
110 for (i = 0; i < HASH_SIZE; i++)
111 INIT_FLIST_HEAD(&hash[i]);
116 #endif /* FIO_DEBUG_TIME */
118 #ifdef FIO_DEBUG_TIME
119 void fio_gettime(struct timeval *tp, void *caller)
121 void fio_gettime(struct timeval *tp, void fio_unused *caller)
124 #ifdef FIO_DEBUG_TIME
126 caller = __builtin_return_address(0);
128 gtod_log_caller(caller);
131 memcpy(tp, fio_tv, sizeof(*tp));
135 switch (fio_clock_source) {
137 gettimeofday(tp, NULL);
142 #ifdef FIO_HAVE_CLOCK_MONOTONIC
143 if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
145 if (clock_gettime(CLOCK_REALTIME, &ts) < 0) {
147 log_err("fio: clock_gettime fails\n");
151 tp->tv_sec = ts.tv_sec;
152 tp->tv_usec = ts.tv_nsec / 1000;
155 #ifdef ARCH_HAVE_CPU_CLOCK
157 unsigned long long usecs, t;
160 if (t < last_cycles) {
161 dprint(FD_TIME, "CPU clock going back in time\n");
165 usecs = t / cycles_per_usec;
166 tp->tv_sec = usecs / 1000000;
167 tp->tv_usec = usecs % 1000000;
173 log_err("fio: invalid clock source %d\n", fio_clock_source);
178 * If Linux is using the tsc clock on non-synced processors,
179 * sometimes time can appear to drift backwards. Fix that up.
182 if (tp->tv_sec < last_tv.tv_sec)
183 tp->tv_sec = last_tv.tv_sec;
184 else if (last_tv.tv_sec == tp->tv_sec &&
185 tp->tv_usec < last_tv.tv_usec)
186 tp->tv_usec = last_tv.tv_usec;
189 memcpy(&last_tv, tp, sizeof(*tp));
192 #ifdef ARCH_HAVE_CPU_CLOCK
193 static unsigned long get_cycles_per_usec(void)
196 unsigned long long c_s, c_e;
198 gettimeofday(&s, NULL);
199 c_s = get_cpu_clock();
201 unsigned long long elapsed;
203 gettimeofday(&e, NULL);
204 elapsed = utime_since(&s, &e);
205 if (elapsed >= 1280) {
206 c_e = get_cpu_clock();
211 return (c_e - c_s + 127) >> 7;
214 #define NR_TIME_ITERS 50
216 static void calibrate_cpu_clock(void)
218 double delta, mean, S;
219 unsigned long avg, cycles[NR_TIME_ITERS];
222 cycles[0] = get_cycles_per_usec();
223 S = delta = mean = 0.0;
224 for (i = 0; i < NR_TIME_ITERS; i++) {
225 cycles[i] = get_cycles_per_usec();
226 delta = cycles[i] - mean;
228 mean += delta / (i + 1.0);
229 S += delta * (cycles[i] - mean);
233 S = sqrt(S / (NR_TIME_ITERS - 1.0));
236 for (i = 0; i < NR_TIME_ITERS; i++) {
237 double this = cycles[i];
239 if ((fmax(this, mean) - fmin(this, mean)) > S)
245 S /= (double) NR_TIME_ITERS;
248 for (i = 0; i < NR_TIME_ITERS; i++)
249 dprint(FD_TIME, "cycles[%d]=%lu\n", i, cycles[i] / 10);
252 avg = (avg + 9) / 10;
253 dprint(FD_TIME, "avg: %lu\n", avg);
254 dprint(FD_TIME, "mean=%f, S=%f\n", mean, S);
256 cycles_per_usec = avg;
259 static void calibrate_cpu_clock(void)
264 void fio_clock_init(void)
266 if (fio_clock_source == fio_clock_source_inited)
270 fio_clock_source_inited = fio_clock_source;
271 calibrate_cpu_clock();
274 * If the arch sets tsc_reliable != 0, then it must be good enough
275 * to use as THE clock source. For x86 CPUs, this means the TSC
276 * runs at a constant rate and is synced across CPU cores.
279 if (!fio_clock_source_set)
280 fio_clock_source = CS_CPUCLOCK;
281 } else if (fio_clock_source == CS_CPUCLOCK)
282 log_info("fio: clocksource=cpu may not be reliable\n");
285 unsigned long long utime_since(struct timeval *s, struct timeval *e)
288 unsigned long long ret;
290 sec = e->tv_sec - s->tv_sec;
291 usec = e->tv_usec - s->tv_usec;
292 if (sec > 0 && usec < 0) {
298 * time warp bug on some kernels?
300 if (sec < 0 || (sec == 0 && usec < 0))
303 ret = sec * 1000000ULL + usec;
308 unsigned long long utime_since_now(struct timeval *s)
312 fio_gettime(&t, NULL);
313 return utime_since(s, &t);
316 unsigned long mtime_since(struct timeval *s, struct timeval *e)
320 sec = e->tv_sec - s->tv_sec;
321 usec = e->tv_usec - s->tv_usec;
322 if (sec > 0 && usec < 0) {
327 if (sec < 0 || (sec == 0 && usec < 0))
337 unsigned long mtime_since_now(struct timeval *s)
340 void *p = __builtin_return_address(0);
343 return mtime_since(s, &t);
346 unsigned long time_since_now(struct timeval *s)
348 return mtime_since_now(s) / 1000;