4 #include "steadystate.h"
5 #include "helper_thread.h"
7 bool steadystate = false;
9 void steadystate_setup(void)
12 struct thread_data *td, *prev_td;
18 * if group reporting is enabled, identify the last td
19 * for each group and use it for storing steady state
25 if (td->ts.ss == NULL)
28 if (!td->o.group_reporting) {
29 steadystate_alloc(td);
33 if (prev_groupid != td->groupid) {
34 if (prev_td != NULL) {
35 prev_td->ss.last_in_group = 1;
36 steadystate_alloc(prev_td);
38 prev_groupid = td->groupid;
43 if (prev_td != NULL && prev_td->o.group_reporting) {
44 prev_td->ss.last_in_group = 1;
45 steadystate_alloc(prev_td);
49 void steadystate_alloc(struct thread_data *td)
53 td->ss.bw_data = malloc(td->ss.dur * sizeof(unsigned long));
54 td->ss.iops_data = malloc(td->ss.dur * sizeof(unsigned long));
55 /* initialize so that it is obvious if the cache is not full in the output */
56 for (i = 0; i < td->ss.dur; i++)
57 td->ss.iops_data[i] = td->ss.bw_data[i] = 0;
60 static bool steadystate_slope(unsigned long iops, unsigned long bw,
61 struct thread_data *td)
65 struct steadystate_data *ss = &td->ss;
66 unsigned long new_val = ss->check_iops ? iops : bw;
68 ss->bw_data[ss->tail] = bw;
69 ss->iops_data[ss->tail] = iops;
71 if (ss->tail < ss->head || (ss->tail - ss->head == ss->dur - 1)) {
72 if (ss->sum_y == 0) { /* first time through */
73 for(i = 0; i < ss->dur; i++) {
74 ss->sum_y += ss->check_iops ? ss->iops_data[i] : ss->bw_data[i];
78 ss->sum_xy += (ss->check_iops ? ss->iops_data[j] : ss->bw_data[j]) * i;
80 } else { /* easy to update the sums */
81 ss->sum_y -= ss->oldest_y;
83 ss->sum_xy = ss->sum_xy - ss->sum_y + ss->dur * new_val;
86 ss->oldest_y = ss->check_iops ? ss->iops_data[ss->head] : ss->bw_data[ss->head];
89 * calculate slope as (sum_xy - sum_x * sum_y / n) / (sum_(x^2) - (sum_x)^2 / n)
90 * This code assumes that all x values are equally spaced when they are often
91 * off by a few milliseconds. This assumption greatly simplifies the
94 ss->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);
95 ss->criterion = ss->pct ? 100.0 * ss->slope / (ss->sum_y / ss->dur) : ss->slope;
97 dprint(FD_STEADYSTATE, "sum_y: %llu, sum_xy: %llu, slope: %f, criterion: %f, limit: %f\n",
98 ss->sum_y, ss->sum_xy, ss->slope, ss->criterion, ss->limit);
100 result = ss->criterion * (ss->criterion < 0.0 ? -1.0 : 1.0);
101 if (result < ss->limit)
105 ss->tail = (ss->tail + 1) % ss->dur;
106 if (ss->tail <= ss->head)
107 ss->head = (ss->head + 1) % ss->dur;
112 static bool steadystate_deviation(unsigned long iops, unsigned long bw,
113 struct thread_data *td)
119 struct steadystate_data *ss = &td->ss;
121 ss->bw_data[ss->tail] = bw;
122 ss->iops_data[ss->tail] = iops;
124 if (ss->tail < ss->head || (ss->tail - ss->head == ss->dur - 1)) {
125 if (ss->sum_y == 0) { /* first time through */
126 for(i = 0; i < ss->dur; i++)
127 ss->sum_y += ss->check_iops ? ss->iops_data[i] : ss->bw_data[i];
128 } else { /* easy to update the sum */
129 ss->sum_y -= ss->oldest_y;
130 ss->sum_y += ss->check_iops ? ss->iops_data[ss->tail] : ss->bw_data[ss->tail];
133 ss->oldest_y = ss->check_iops ? ss->iops_data[ss->head] : ss->bw_data[ss->head];
134 mean = (double) ss->sum_y / ss->dur;
137 for (i = 0; i < ss->dur; i++) {
138 diff = (double) (ss->check_iops ? ss->iops_data[i] : ss->bw_data[i]) - mean;
139 ss->deviation = max(ss->deviation, diff * (diff < 0.0 ? -1.0 : 1.0));
142 ss->criterion = ss->pct ? 100.0 * ss->deviation / mean : ss->deviation;
144 dprint(FD_STEADYSTATE, "sum_y: %llu, mean: %f, max diff: %f, objective: %f, limit: %f\n", ss->sum_y, mean, ss->deviation, ss->criterion, ss->limit);
146 if (ss->criterion < ss->limit)
150 ss->tail = (ss->tail + 1) % ss->dur;
151 if (ss->tail <= ss->head)
152 ss->head = (ss->head + 1) % ss->dur;
157 void steadystate_check(void)
159 int i, j, ddir, prev_groupid, group_ramp_time_over = 0;
160 unsigned long rate_time;
161 struct thread_data *td, *td2;
163 unsigned long group_bw = 0, group_iops = 0;
164 unsigned long long td_iops;
165 unsigned long long td_bytes;
170 struct steadystate_data *ss = &td->ss;
172 if (!ss->dur || td->runstate <= TD_SETTING_UP || td->runstate >= TD_EXITED || ss->attained)
177 if (!td->o.group_reporting ||
178 (td->o.group_reporting && td->groupid != prev_groupid)) {
181 group_ramp_time_over = 0;
183 prev_groupid = td->groupid;
185 fio_gettime(&now, NULL);
186 if (ss->ramp_time && !ss->ramp_time_over)
188 * Begin recording data one second after ss->ramp_time
191 if (utime_since(&td->epoch, &now) >= (ss->ramp_time + 1000000L))
192 ss->ramp_time_over = 1;
195 for (ddir = DDIR_READ; ddir < DDIR_RWDIR_CNT; ddir++) {
196 td_iops += td->io_blocks[ddir];
197 td_bytes += td->io_bytes[ddir];
201 rate_time = mtime_since(&ss->prev_time, &now);
202 memcpy(&ss->prev_time, &now, sizeof(now));
205 * Begin monitoring when job starts but don't actually use
206 * data in checking stopping criterion until ss->ramp_time is
207 * over. This ensures that we will have a sane value in
208 * prev_iops/bw the first time through after ss->ramp_time
211 if (ss->ramp_time_over) {
212 group_bw += 1000 * (td_bytes - ss->prev_bytes) / rate_time;
213 group_iops += 1000 * (td_iops - ss->prev_iops) / rate_time;
214 ++group_ramp_time_over;
216 ss->prev_iops = td_iops;
217 ss->prev_bytes = td_bytes;
219 if (td->o.group_reporting && !ss->last_in_group)
222 /* don't begin checking criterion until ss->ramp_time is over for at least one thread in group */
223 if (!group_ramp_time_over)
226 dprint(FD_STEADYSTATE, "steadystate_check() thread: %d, groupid: %u, rate_msec: %ld, iops: %lu, bw: %lu, head: %d, tail: %d\n",
227 i, td->groupid, rate_time, group_iops, group_bw, ss->head, ss->tail);
229 if (steadystate_check_slope(&td->o))
230 ret = steadystate_slope(group_iops, group_bw, td);
232 ret = steadystate_deviation(group_iops, group_bw, td);
235 if (td->o.group_reporting) {
236 for_each_td(td2, j) {
237 if (td2->groupid == td->groupid) {
238 td2->ss.attained = 1;
239 fio_mark_td_terminate(td2);
244 fio_mark_td_terminate(td);