2 #include "steadystate.h"
3 #include "helper_thread.h"
5 void steadystate_setup()
8 struct thread_data *td, *prev_td;
14 * if group reporting is enabled, identify the last td
15 * for each group and use it for storing steady state
21 if (!td->o.group_reporting)
24 if (prev_groupid != td->groupid) {
26 prev_td->ss.last_in_group = 1;
27 prev_groupid = td->groupid;
32 if (prev_td != NULL && prev_td->o.group_reporting)
33 prev_td->ss.last_in_group = 1;
36 void steadystate_check()
38 int i, j, ddir, prev_groupid, group_ramp_time_over = 0;
39 unsigned long rate_time;
40 struct thread_data *td, *td2;
42 unsigned long group_bw = 0, group_iops = 0;
43 unsigned long long td_iops;
44 unsigned long long td_bytes;
48 struct steadystate_data *ss = &td->ss;
50 if (!ss->dur || td->runstate <= TD_SETTING_UP || td->runstate >= TD_EXITED || ss->attained)
55 if (!td->o.group_reporting ||
56 (td->o.group_reporting && td->groupid != prev_groupid)) {
59 group_ramp_time_over = 0;
61 prev_groupid = td->groupid;
63 fio_gettime(&now, NULL);
64 if (ss->ramp_time && !ss->ramp_time_over)
66 * Begin recording data one second after ss->ramp_time
69 if (utime_since(&td->epoch, &now) >= (ss->ramp_time + 1000000L))
70 ss->ramp_time_over = 1;
73 for (ddir = DDIR_READ; ddir < DDIR_RWDIR_CNT; ddir++) {
74 td_iops += td->io_blocks[ddir];
75 td_bytes += td->io_bytes[ddir];
79 rate_time = mtime_since(&ss->prev_time, &now);
80 memcpy(&ss->prev_time, &now, sizeof(now));
83 * Begin monitoring when job starts but don't actually use
84 * data in checking stopping criterion until ss->ramp_time is
85 * over. This ensures that we will have a sane value in
86 * prev_iops/bw the first time through after ss->ramp_time
89 if (ss->ramp_time_over) {
90 group_bw += 1000 * (td_bytes - ss->prev_bytes) / rate_time;
91 group_iops += 1000 * (td_iops - ss->prev_iops) / rate_time;
92 ++group_ramp_time_over;
94 ss->prev_iops = td_iops;
95 ss->prev_bytes = td_bytes;
97 if (td->o.group_reporting && !ss->last_in_group)
100 /* don't begin checking criterion until ss->ramp_time is over for at least one thread in group */
101 if (!group_ramp_time_over)
104 dprint(FD_STEADYSTATE, "steadystate_check() thread: %d, groupid: %u, rate_msec: %ld, iops: %lu, bw: %lu, head: %d, tail: %d\n",
105 i, td->groupid, rate_time, group_iops, group_bw, ss->head, ss->tail);
107 if (ss->evaluate(group_iops, group_bw, td))
109 if (td->o.group_reporting)
110 for_each_td(td2, j) {
111 if (td2->groupid == td->groupid) {
112 td2->ss.attained = 1;
113 fio_mark_td_terminate(td2);
118 fio_mark_td_terminate(td);
124 bool steadystate_slope(unsigned long iops, unsigned long bw, struct thread_data *td)
129 struct steadystate_data *ss = &td->ss;
131 ss->cache[ss->tail] = ss->check_iops ? iops : bw;
133 if (ss->tail < ss->head || (ss->tail - ss->head == ss->dur - 1))
135 if (ss->sum_y == 0) /* first time through */
137 for(i = 0; i < ss->dur; i++)
139 ss->sum_y += ss->cache[i];
143 ss->sum_xy += ss->cache[x] * i;
145 } else { /* easy to update the sums */
146 ss->sum_y -= ss->oldest_y;
147 ss->sum_y += ss->cache[ss->tail];
148 ss->sum_xy = ss->sum_xy - ss->sum_y + ss->dur * ss->cache[ss->tail];
151 ss->oldest_y = ss->cache[ss->head];
154 * calculate slope as (sum_xy - sum_x * sum_y / n) / (sum_(x^2) - (sum_x)^2 / n)
155 * This code assumes that all x values are equally spaced when they are often
156 * off by a few milliseconds. This assumption greatly simplifies the
159 slope = (ss->sum_xy - (double) ss->sum_x * ss->sum_y / ss->dur) / (ss->sum_x_sq - (double) ss->sum_x * ss->sum_x / ss->dur);
160 ss->criterion = ss->pct ? slope / (ss->sum_y / ss->dur) * 100.0: slope;
162 dprint(FD_STEADYSTATE, "sum_y: %llu, sum_xy: %llu, slope: %f, criterion: %f, limit: %f\n",
163 ss->sum_y, ss->sum_xy, slope, ss->criterion, ss->limit);
165 result = ss->criterion * (ss->criterion < 0.0 ? -1 : 1);
166 if (result < ss->limit)
170 ss->tail = (ss->tail + 1) % ss->dur;
171 if (ss->tail <= ss->head)
172 ss->head = (ss->head + 1) % ss->dur;
176 bool steadystate_deviation(unsigned long iops, unsigned long bw, struct thread_data *td)
183 struct steadystate_data *ss = &td->ss;
185 ss->cache[ss->tail] = ss->check_iops ? iops : bw;
187 if (ss->tail < ss->head || (ss->tail - ss->head == ss->dur - 1))
189 if (ss->sum_y == 0) /* first time through */
191 for(i = 0; i < ss->dur; i++)
192 ss->sum_y += ss->cache[i];
193 } else { /* easy to update the sum */
194 ss->sum_y -= ss->oldest_y;
195 ss->sum_y += ss->cache[ss->tail];
198 ss->oldest_y = ss->cache[ss->head];
199 mean = (double) ss->sum_y / ss->dur;
202 for (i = 0; i < ss->dur; i++)
204 diff = (double) ss->cache[i] - mean;
205 deviation = max(deviation, diff * (diff < 0.0 ? -1 : 1));
208 ss->criterion = ss->pct ? deviation / mean * 100.0 : deviation;
210 dprint(FD_STEADYSTATE, "sum_y: %llu, mean: %f, max diff: %f, objective: %f, limit: %f\n", ss->sum_y, mean, deviation, ss->criterion, ss->limit);
212 if (ss->criterion < ss->limit)
216 ss->tail = (ss->tail + 1) % ss->dur;
217 if (ss->tail <= ss->head)
218 ss->head = (ss->head + 1) % ss->dur;