4 #include "steadystate.h"
5 #include "helper_thread.h"
7 bool steadystate_enabled = false;
9 static void steadystate_alloc(struct thread_data *td)
11 td->ss.bw_data = calloc(td->ss.dur, sizeof(uint64_t));
12 td->ss.iops_data = calloc(td->ss.dur, sizeof(uint64_t));
14 td->ss.state |= FIO_SS_DATA;
17 void steadystate_setup(void)
20 struct thread_data *td, *prev_td;
22 if (!steadystate_enabled)
26 * if group reporting is enabled, identify the last td
27 * for each group and use it for storing steady state
36 if (!td->o.group_reporting) {
37 steadystate_alloc(td);
41 if (prev_groupid != td->groupid) {
42 if (prev_td != NULL) {
43 steadystate_alloc(prev_td);
45 prev_groupid = td->groupid;
50 if (prev_td != NULL && prev_td->o.group_reporting) {
51 steadystate_alloc(prev_td);
55 static bool steadystate_slope(uint64_t iops, uint64_t bw,
56 struct thread_data *td)
60 struct steadystate_data *ss = &td->ss;
63 ss->bw_data[ss->tail] = bw;
64 ss->iops_data[ss->tail] = iops;
66 if (ss->state & FIO_SS_IOPS)
71 if (ss->state & FIO_SS_BUFFER_FULL || ss->tail - ss->head == ss->dur - 1) {
72 if (!(ss->state & FIO_SS_BUFFER_FULL)) {
73 /* first time through */
74 for(i = 0, ss->sum_y = 0; i < ss->dur; i++) {
75 if (ss->state & FIO_SS_IOPS)
76 ss->sum_y += ss->iops_data[i];
78 ss->sum_y += ss->bw_data[i];
79 j = (ss->head + i) % ss->dur;
80 if (ss->state & FIO_SS_IOPS)
81 ss->sum_xy += i * ss->iops_data[j];
83 ss->sum_xy += i * ss->bw_data[j];
85 ss->state |= FIO_SS_BUFFER_FULL;
86 } else { /* easy to update the sums */
87 ss->sum_y -= ss->oldest_y;
89 ss->sum_xy = ss->sum_xy - ss->sum_y + ss->dur * new_val;
92 if (ss->state & FIO_SS_IOPS)
93 ss->oldest_y = ss->iops_data[ss->head];
95 ss->oldest_y = ss->bw_data[ss->head];
98 * calculate slope as (sum_xy - sum_x * sum_y / n) / (sum_(x^2)
99 * - (sum_x)^2 / n) This code assumes that all x values are
100 * equally spaced when they are often off by a few milliseconds.
101 * This assumption greatly simplifies the calculations.
103 ss->slope = (ss->sum_xy - (double) ss->sum_x * ss->sum_y / ss->dur) /
104 (ss->sum_x_sq - (double) ss->sum_x * ss->sum_x / ss->dur);
105 if (ss->state & FIO_SS_PCT)
106 ss->criterion = 100.0 * ss->slope / (ss->sum_y / ss->dur);
108 ss->criterion = ss->slope;
110 dprint(FD_STEADYSTATE, "sum_y: %llu, sum_xy: %llu, slope: %f, "
111 "criterion: %f, limit: %f\n",
112 (unsigned long long) ss->sum_y,
113 (unsigned long long) ss->sum_xy,
114 ss->slope, ss->criterion, ss->limit);
116 result = ss->criterion * (ss->criterion < 0.0 ? -1.0 : 1.0);
117 if (result < ss->limit)
121 ss->tail = (ss->tail + 1) % ss->dur;
122 if (ss->tail <= ss->head)
123 ss->head = (ss->head + 1) % ss->dur;
128 static bool steadystate_deviation(uint64_t iops, uint64_t bw,
129 struct thread_data *td)
135 struct steadystate_data *ss = &td->ss;
137 ss->bw_data[ss->tail] = bw;
138 ss->iops_data[ss->tail] = iops;
140 if (ss->state & FIO_SS_BUFFER_FULL || ss->tail - ss->head == ss->dur - 1) {
141 if (!(ss->state & FIO_SS_BUFFER_FULL)) {
142 /* first time through */
143 for(i = 0, ss->sum_y = 0; i < ss->dur; i++)
144 if (ss->state & FIO_SS_IOPS)
145 ss->sum_y += ss->iops_data[i];
147 ss->sum_y += ss->bw_data[i];
148 ss->state |= FIO_SS_BUFFER_FULL;
149 } else { /* easy to update the sum */
150 ss->sum_y -= ss->oldest_y;
151 if (ss->state & FIO_SS_IOPS)
152 ss->sum_y += ss->iops_data[ss->tail];
154 ss->sum_y += ss->bw_data[ss->tail];
157 if (ss->state & FIO_SS_IOPS)
158 ss->oldest_y = ss->iops_data[ss->head];
160 ss->oldest_y = ss->bw_data[ss->head];
162 mean = (double) ss->sum_y / ss->dur;
165 for (i = 0; i < ss->dur; i++) {
166 if (ss->state & FIO_SS_IOPS)
167 diff = ss->iops_data[i] - mean;
169 diff = ss->bw_data[i] - mean;
170 ss->deviation = max(ss->deviation, diff * (diff < 0.0 ? -1.0 : 1.0));
173 if (ss->state & FIO_SS_PCT)
174 ss->criterion = 100.0 * ss->deviation / mean;
176 ss->criterion = ss->deviation;
178 dprint(FD_STEADYSTATE, "sum_y: %llu, mean: %f, max diff: %f, "
179 "objective: %f, limit: %f\n",
180 (unsigned long long) ss->sum_y, mean,
181 ss->deviation, ss->criterion, ss->limit);
183 if (ss->criterion < ss->limit)
187 ss->tail = (ss->tail + 1) % ss->dur;
188 if (ss->tail <= ss->head)
189 ss->head = (ss->head + 1) % ss->dur;
194 void steadystate_check(void)
196 int i, j, ddir, prev_groupid, group_ramp_time_over = 0;
197 unsigned long rate_time;
198 struct thread_data *td, *td2;
200 uint64_t group_bw = 0, group_iops = 0;
201 uint64_t td_iops, td_bytes;
206 struct steadystate_data *ss = &td->ss;
208 if (!ss->dur || td->runstate <= TD_SETTING_UP ||
209 td->runstate >= TD_EXITED || !ss->state ||
210 ss->state & FIO_SS_ATTAINED)
215 if (!td->o.group_reporting ||
216 (td->o.group_reporting && td->groupid != prev_groupid)) {
219 group_ramp_time_over = 0;
221 prev_groupid = td->groupid;
223 fio_gettime(&now, NULL);
224 if (ss->ramp_time && !(ss->state & FIO_SS_RAMP_OVER)) {
226 * Begin recording data one second after ss->ramp_time
229 if (utime_since(&td->epoch, &now) >= (ss->ramp_time + 1000000L))
230 ss->state |= FIO_SS_RAMP_OVER;
234 for (ddir = 0; ddir < DDIR_RWDIR_CNT; ddir++) {
235 td_iops += td->io_blocks[ddir];
236 td_bytes += td->io_bytes[ddir];
240 rate_time = mtime_since(&ss->prev_time, &now);
241 memcpy(&ss->prev_time, &now, sizeof(now));
244 * Begin monitoring when job starts but don't actually use
245 * data in checking stopping criterion until ss->ramp_time is
246 * over. This ensures that we will have a sane value in
247 * prev_iops/bw the first time through after ss->ramp_time
250 if (ss->state & FIO_SS_RAMP_OVER) {
251 group_bw += 1000 * (td_bytes - ss->prev_bytes) / rate_time;
252 group_iops += 1000 * (td_iops - ss->prev_iops) / rate_time;
253 ++group_ramp_time_over;
255 ss->prev_iops = td_iops;
256 ss->prev_bytes = td_bytes;
258 if (td->o.group_reporting && !(ss->state & FIO_SS_DATA))
262 * Don't begin checking criterion until ss->ramp_time is over
263 * for at least one thread in group
265 if (!group_ramp_time_over)
268 dprint(FD_STEADYSTATE, "steadystate_check() thread: %d, "
269 "groupid: %u, rate_msec: %ld, "
270 "iops: %llu, bw: %llu, head: %d, tail: %d\n",
271 i, td->groupid, rate_time,
272 (unsigned long long) group_iops,
273 (unsigned long long) group_bw,
276 if (ss->state & FIO_SS_SLOPE)
277 ret = steadystate_slope(group_iops, group_bw, td);
279 ret = steadystate_deviation(group_iops, group_bw, td);
282 if (td->o.group_reporting) {
283 for_each_td(td2, j) {
284 if (td2->groupid == td->groupid) {
285 td2->ss.state |= FIO_SS_ATTAINED;
286 fio_mark_td_terminate(td2);
290 ss->state |= FIO_SS_ATTAINED;
291 fio_mark_td_terminate(td);
297 int td_steadystate_init(struct thread_data *td)
299 struct steadystate_data *ss = &td->ss;
300 struct thread_options *o = &td->o;
301 struct thread_data *td2;
304 memset(ss, 0, sizeof(*ss));
307 steadystate_enabled = true;
308 o->ss_dur /= 1000000L;
310 /* put all steady state info in one place */
312 ss->limit = o->ss_limit.u.f;
313 ss->ramp_time = o->ss_ramp_time;
315 ss->state = o->ss_state;
316 if (!td->ss.ramp_time)
317 ss->state |= FIO_SS_RAMP_OVER;
319 ss->sum_x = o->ss_dur * (o->ss_dur - 1) / 2;
320 ss->sum_x_sq = (o->ss_dur - 1) * (o->ss_dur) * (2*o->ss_dur - 1) / 6;
323 /* make sure that ss options are consistent within reporting group */
324 for_each_td(td2, j) {
325 if (td2->groupid == td->groupid) {
326 struct steadystate_data *ss2 = &td2->ss;
328 if (ss2->dur != ss->dur ||
329 ss2->limit != ss->limit ||
330 ss2->ramp_time != ss->ramp_time ||
331 ss2->state != ss->state ||
332 ss2->sum_x != ss->sum_x ||
333 ss2->sum_x_sq != ss->sum_x_sq) {
334 td_verror(td, EINVAL, "job rejected: steadystate options must be consistent within reporting groups");
343 uint64_t steadystate_bw_mean(struct thread_stat *ts)
348 for (i = 0, sum = 0; i < ts->ss_dur; i++)
349 sum += ts->ss_bw_data[i];
351 return sum / ts->ss_dur;
354 uint64_t steadystate_iops_mean(struct thread_stat *ts)
359 for (i = 0, sum = 0; i < ts->ss_dur; i++)
360 sum += ts->ss_iops_data[i];
362 return sum / ts->ss_dur;