steadystate: bug fixes
[fio.git] / steadystate.c
CommitLineData
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1#include <stdlib.h>
2
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3#include "fio.h"
4#include "steadystate.h"
5#include "helper_thread.h"
6
84784e07 7bool steadystate_enabled = false;
4cd5b75b 8
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9static void steadystate_alloc(struct thread_data *td)
10{
11 int i;
12
13 td->ss.bw_data = malloc(td->ss.dur * sizeof(unsigned long));
14 td->ss.iops_data = malloc(td->ss.dur * sizeof(unsigned long));
15 /* initialize so that it is obvious if the cache is not full in the output */
16 for (i = 0; i < td->ss.dur; i++)
17 td->ss.iops_data[i] = td->ss.bw_data[i] = 0;
18}
19
4cd5b75b 20void steadystate_setup(void)
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21{
22 int i, prev_groupid;
23 struct thread_data *td, *prev_td;
24
84784e07 25 if (!steadystate_enabled)
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26 return;
27
28 /*
29 * if group reporting is enabled, identify the last td
30 * for each group and use it for storing steady state
31 * data
32 */
33 prev_groupid = -1;
34 prev_td = NULL;
35 for_each_td(td, i) {
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36 if (td->ts.ss == NULL)
37 continue;
38
39 if (!td->o.group_reporting) {
40 steadystate_alloc(td);
16e56d25 41 continue;
ba8fb6f6 42 }
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43
44 if (prev_groupid != td->groupid) {
ba8fb6f6 45 if (prev_td != NULL) {
5b4b6586 46 prev_td->ss.state |= __FIO_SS_LAST;
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47 steadystate_alloc(prev_td);
48 }
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49 prev_groupid = td->groupid;
50 }
51 prev_td = td;
52 }
53
ba8fb6f6 54 if (prev_td != NULL && prev_td->o.group_reporting) {
5b4b6586 55 prev_td->ss.state |= __FIO_SS_LAST;
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56 steadystate_alloc(prev_td);
57 }
58}
59
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60static bool steadystate_slope(unsigned long iops, unsigned long bw,
61 struct thread_data *td)
16e56d25 62{
ba8fb6f6 63 int i, j;
16e56d25 64 double result;
16e56d25 65 struct steadystate_data *ss = &td->ss;
7be78a8a 66 unsigned long new_val;
16e56d25 67
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68 ss->bw_data[ss->tail] = bw;
69 ss->iops_data[ss->tail] = iops;
16e56d25 70
5b4b6586 71 if (ss->state & __FIO_SS_IOPS)
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72 new_val = iops;
73 else
74 new_val = bw;
75
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76 if (ss->tail < ss->head || (ss->tail - ss->head == ss->dur - 1)) {
77 if (ss->sum_y == 0) { /* first time through */
78 for(i = 0; i < ss->dur; i++) {
5b4b6586 79 if (ss->state & __FIO_SS_IOPS)
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80 ss->sum_y += ss->iops_data[i];
81 else
82 ss->sum_y += ss->bw_data[i];
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83 j = ss->head + i;
84 if (j >= ss->dur)
85 j -= ss->dur;
5b4b6586 86 if (ss->state & __FIO_SS_IOPS)
94f218f6 87 ss->sum_xy += i * ss->iops_data[j];
7be78a8a 88 else
94f218f6 89 ss->sum_xy += i * ss->bw_data[j];
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90 }
91 } else { /* easy to update the sums */
92 ss->sum_y -= ss->oldest_y;
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93 ss->sum_y += new_val;
94 ss->sum_xy = ss->sum_xy - ss->sum_y + ss->dur * new_val;
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95 }
96
5b4b6586 97 if (ss->state & __FIO_SS_IOPS)
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98 ss->oldest_y = ss->iops_data[ss->head];
99 else
100 ss->oldest_y = ss->bw_data[ss->head];
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101
102 /*
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103 * calculate slope as (sum_xy - sum_x * sum_y / n) / (sum_(x^2)
104 * - (sum_x)^2 / n) This code assumes that all x values are
105 * equally spaced when they are often off by a few milliseconds.
106 * This assumption greatly simplifies the calculations.
16e56d25 107 */
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108 ss->slope = (ss->sum_xy - (double) ss->sum_x * ss->sum_y / ss->dur) /
109 (ss->sum_x_sq - (double) ss->sum_x * ss->sum_x / ss->dur);
110 if (ss->pct)
111 ss->criterion = 100.0 * ss->slope / (ss->sum_y / ss->dur);
112 else
113 ss->criterion = ss->slope;
16e56d25 114
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115 dprint(FD_STEADYSTATE, "sum_y: %llu, sum_xy: %llu, slope: %f, "
116 "criterion: %f, limit: %f\n",
117 ss->sum_y, ss->sum_xy, ss->slope,
118 ss->criterion, ss->limit);
16e56d25 119
6da94b07 120 result = ss->criterion * (ss->criterion < 0.0 ? -1.0 : 1.0);
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121 if (result < ss->limit)
122 return true;
123 }
124
125 ss->tail = (ss->tail + 1) % ss->dur;
126 if (ss->tail <= ss->head)
127 ss->head = (ss->head + 1) % ss->dur;
4cd5b75b 128
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129 return false;
130}
131
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132static bool steadystate_deviation(unsigned long iops, unsigned long bw,
133 struct thread_data *td)
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134{
135 int i;
136 double diff;
137 double mean;
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138
139 struct steadystate_data *ss = &td->ss;
140
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141 ss->bw_data[ss->tail] = bw;
142 ss->iops_data[ss->tail] = iops;
16e56d25 143
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144 if (ss->tail < ss->head || (ss->tail - ss->head == ss->dur - 1)) {
145 if (ss->sum_y == 0) { /* first time through */
16e56d25 146 for(i = 0; i < ss->dur; i++)
5b4b6586 147 if (ss->state & __FIO_SS_IOPS)
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148 ss->sum_y += ss->iops_data[i];
149 else
150 ss->sum_y += ss->bw_data[i];
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151 } else { /* easy to update the sum */
152 ss->sum_y -= ss->oldest_y;
5b4b6586 153 if (ss->state & __FIO_SS_IOPS)
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154 ss->sum_y += ss->iops_data[ss->tail];
155 else
156 ss->sum_y += ss->bw_data[ss->tail];
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157 }
158
5b4b6586 159 if (ss->state & __FIO_SS_IOPS)
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160 ss->oldest_y = ss->iops_data[ss->head];
161 else
162 ss->oldest_y = ss->bw_data[ss->head];
163
16e56d25 164 mean = (double) ss->sum_y / ss->dur;
ba8fb6f6 165 ss->deviation = 0.0;
16e56d25 166
4cd5b75b 167 for (i = 0; i < ss->dur; i++) {
5b4b6586 168 if (ss->state & __FIO_SS_IOPS)
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169 diff = ss->iops_data[i] - mean;
170 else
171 diff = ss->bw_data[i] - mean;
6da94b07 172 ss->deviation = max(ss->deviation, diff * (diff < 0.0 ? -1.0 : 1.0));
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173 }
174
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175 if (ss->pct)
176 ss->criterion = 100.0 * ss->deviation / mean;
177 else
178 ss->criterion = ss->deviation;
16e56d25 179
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180 dprint(FD_STEADYSTATE, "sum_y: %llu, mean: %f, max diff: %f, "
181 "objective: %f, limit: %f\n",
182 ss->sum_y, mean, ss->deviation,
183 ss->criterion, ss->limit);
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184
185 if (ss->criterion < ss->limit)
186 return true;
187 }
188
189 ss->tail = (ss->tail + 1) % ss->dur;
190 if (ss->tail <= ss->head)
191 ss->head = (ss->head + 1) % ss->dur;
4cd5b75b 192
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193 return false;
194}
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195
196void steadystate_check(void)
197{
198 int i, j, ddir, prev_groupid, group_ramp_time_over = 0;
199 unsigned long rate_time;
200 struct thread_data *td, *td2;
201 struct timeval now;
202 unsigned long group_bw = 0, group_iops = 0;
203 unsigned long long td_iops;
204 unsigned long long td_bytes;
205 bool ret;
206
207 prev_groupid = -1;
208 for_each_td(td, i) {
209 struct steadystate_data *ss = &td->ss;
210
7be78a8a 211 if (!ss->dur || td->runstate <= TD_SETTING_UP ||
5b4b6586 212 td->runstate >= TD_EXITED || (ss->state & __FIO_SS_ATTAINED))
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213 continue;
214
215 td_iops = 0;
216 td_bytes = 0;
217 if (!td->o.group_reporting ||
218 (td->o.group_reporting && td->groupid != prev_groupid)) {
219 group_bw = 0;
220 group_iops = 0;
221 group_ramp_time_over = 0;
222 }
223 prev_groupid = td->groupid;
224
225 fio_gettime(&now, NULL);
5b4b6586 226 if (ss->ramp_time && !(ss->state & __FIO_SS_RAMP_OVER)) {
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227 /*
228 * Begin recording data one second after ss->ramp_time
229 * has elapsed
230 */
231 if (utime_since(&td->epoch, &now) >= (ss->ramp_time + 1000000L))
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232 ss->state |= __FIO_SS_RAMP_OVER;
233 }
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234
235 td_io_u_lock(td);
236 for (ddir = DDIR_READ; ddir < DDIR_RWDIR_CNT; ddir++) {
237 td_iops += td->io_blocks[ddir];
238 td_bytes += td->io_bytes[ddir];
239 }
240 td_io_u_unlock(td);
241
242 rate_time = mtime_since(&ss->prev_time, &now);
243 memcpy(&ss->prev_time, &now, sizeof(now));
244
245 /*
246 * Begin monitoring when job starts but don't actually use
247 * data in checking stopping criterion until ss->ramp_time is
248 * over. This ensures that we will have a sane value in
249 * prev_iops/bw the first time through after ss->ramp_time
250 * is done.
251 */
5b4b6586 252 if (ss->state & __FIO_SS_RAMP_OVER) {
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253 group_bw += 1000 * (td_bytes - ss->prev_bytes) / rate_time;
254 group_iops += 1000 * (td_iops - ss->prev_iops) / rate_time;
255 ++group_ramp_time_over;
256 }
257 ss->prev_iops = td_iops;
258 ss->prev_bytes = td_bytes;
259
5b4b6586 260 if (td->o.group_reporting && !(ss->state & __FIO_SS_LAST))
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261 continue;
262
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263 /*
264 * Don't begin checking criterion until ss->ramp_time is over
265 * for at least one thread in group
266 */
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267 if (!group_ramp_time_over)
268 continue;
269
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270 dprint(FD_STEADYSTATE, "steadystate_check() thread: %d, "
271 "groupid: %u, rate_msec: %ld, "
272 "iops: %lu, bw: %lu, head: %d, tail: %d\n",
273 i, td->groupid, rate_time, group_iops,
274 group_bw, ss->head, ss->tail);
4cd5b75b 275
f0c50c66 276 if (td->o.ss & __FIO_SS_SLOPE)
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277 ret = steadystate_slope(group_iops, group_bw, td);
278 else
279 ret = steadystate_deviation(group_iops, group_bw, td);
280
281 if (ret) {
282 if (td->o.group_reporting) {
283 for_each_td(td2, j) {
284 if (td2->groupid == td->groupid) {
5b4b6586 285 td2->ss.state |= __FIO_SS_ATTAINED;
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286 fio_mark_td_terminate(td2);
287 }
288 }
289 } else {
5b4b6586 290 ss->state |= __FIO_SS_ATTAINED;
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291 fio_mark_td_terminate(td);
292 }
293 }
294 }
295}
296
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297void td_steadystate_init(struct thread_data *td)
298{
299 struct steadystate_data *ss = &td->ss;
300 struct thread_options *o = &td->o;
301
302 memset(ss, 0, sizeof(*ss));
303
304 if (!o->ss_dur)
305 return;
306
307 steadystate_enabled = true;
308 o->ss_dur /= 1000000L;
4cd5b75b 309
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310 /* put all steady state info in one place */
311 ss->dur = o->ss_dur;
312 ss->limit = o->ss_limit.u.f;
313 ss->ramp_time = o->ss_ramp_time;
314 ss->pct = o->ss_pct;
f0c50c66 315
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316 ss->state = o->ss;
317 if (!td->ss.ramp_time)
318 ss->state |= __FIO_SS_RAMP_OVER;
319
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320 ss->sum_x = o->ss_dur * (o->ss_dur - 1) / 2;
321 ss->sum_x_sq = (o->ss_dur - 1) * (o->ss_dur) * (2*o->ss_dur - 1) / 6;
322
323 td->ts.ss = ss;
324}