steadystate.c

   1 #include <stdlib.h>
   2
   3 #include "fio.h"
   4 #include "steadystate.h"
   5 #include "helper_thread.h"
   6
   7 bool steadystate_enabled = false;
   8
   9 static void steadystate_alloc(struct thread_data *td)
  10 {
  11         td->ss.bw_data = calloc(td->ss.dur, sizeof(uint64_t));
  12         td->ss.iops_data = calloc(td->ss.dur, sizeof(uint64_t));
  13
  14         td->ss.state |= __FIO_SS_DATA;
  15 }
  16
  17 void steadystate_setup(void)
  18 {
  19         int i, prev_groupid;
  20         struct thread_data *td, *prev_td;
  21
  22         if (!steadystate_enabled)
  23                 return;
  24
  25         /*
  26          * if group reporting is enabled, identify the last td
  27          * for each group and use it for storing steady state
  28          * data
  29          */
  30         prev_groupid = -1;
  31         prev_td = NULL;
  32         for_each_td(td, i) {
  33                 if (!td->ss.dur)
  34                         continue;
  35
  36                 if (!td->o.group_reporting) {
  37                         steadystate_alloc(td);
  38                         continue;
  39                 }
  40
  41                 if (prev_groupid != td->groupid) {
  42                         if (prev_td != NULL) {
  43                                 steadystate_alloc(prev_td);
  44                         }
  45                         prev_groupid = td->groupid;
  46                 }
  47                 prev_td = td;
  48         }
  49
  50         if (prev_td != NULL && prev_td->o.group_reporting) {
  51                 steadystate_alloc(prev_td);
  52         }
  53 }
  54
  55 static bool steadystate_slope(uint64_t iops, uint64_t bw,
  56                               struct thread_data *td)
  57 {
  58         int i, j;
  59         double result;
  60         struct steadystate_data *ss = &td->ss;
  61         uint64_t new_val;
  62
  63         ss->bw_data[ss->tail] = bw;
  64         ss->iops_data[ss->tail] = iops;
  65
  66         if (ss->state & __FIO_SS_IOPS)
  67                 new_val = iops;
  68         else
  69                 new_val = bw;
  70
  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];
  77                                 else
  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];
  82                                 else
  83                                         ss->sum_xy += i * ss->bw_data[j];
  84                         }
  85                         ss->state |= __FIO_SS_BUFFER_FULL;
  86                 } else {                /* easy to update the sums */
  87                         ss->sum_y -= ss->oldest_y;
  88                         ss->sum_y += new_val;
  89                         ss->sum_xy = ss->sum_xy - ss->sum_y + ss->dur * new_val;
  90                 }
  91
  92                 if (ss->state & __FIO_SS_IOPS)
  93                         ss->oldest_y = ss->iops_data[ss->head];
  94                 else
  95                         ss->oldest_y = ss->bw_data[ss->head];
  96
  97                 /*
  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.
 102                  */
 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);
 107                 else
 108                         ss->criterion = ss->slope;
 109
 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);
 115
 116                 result = ss->criterion * (ss->criterion < 0.0 ? -1.0 : 1.0);
 117                 if (result < ss->limit)
 118                         return true;
 119         }
 120
 121         ss->tail = (ss->tail + 1) % ss->dur;
 122         if (ss->tail <= ss->head)
 123                 ss->head = (ss->head + 1) % ss->dur;
 124
 125         return false;
 126 }
 127
 128 static bool steadystate_deviation(uint64_t iops, uint64_t bw,
 129                                   struct thread_data *td)
 130 {
 131         int i;
 132         double diff;
 133         double mean;
 134
 135         struct steadystate_data *ss = &td->ss;
 136
 137         ss->bw_data[ss->tail] = bw;
 138         ss->iops_data[ss->tail] = iops;
 139
 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];
 146                                 else
 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];
 153                         else
 154                                 ss->sum_y += ss->bw_data[ss->tail];
 155                 }
 156
 157                 if (ss->state & __FIO_SS_IOPS)
 158                         ss->oldest_y = ss->iops_data[ss->head];
 159                 else
 160                         ss->oldest_y = ss->bw_data[ss->head];
 161
 162                 mean = (double) ss->sum_y / ss->dur;
 163                 ss->deviation = 0.0;
 164
 165                 for (i = 0; i < ss->dur; i++) {
 166                         if (ss->state & __FIO_SS_IOPS)
 167                                 diff = ss->iops_data[i] - mean;
 168                         else
 169                                 diff = ss->bw_data[i] - mean;
 170                         ss->deviation = max(ss->deviation, diff * (diff < 0.0 ? -1.0 : 1.0));
 171                 }
 172
 173                 if (ss->state & __FIO_SS_PCT)
 174                         ss->criterion = 100.0 * ss->deviation / mean;
 175                 else
 176                         ss->criterion = ss->deviation;
 177
 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);
 182
 183                 if (ss->criterion < ss->limit)
 184                         return true;
 185         }
 186
 187         ss->tail = (ss->tail + 1) % ss->dur;
 188         if (ss->tail <= ss->head)
 189                 ss->head = (ss->head + 1) % ss->dur;
 190
 191         return false;
 192 }
 193
 194 void steadystate_check(void)
 195 {
 196         int i, j, ddir, prev_groupid, group_ramp_time_over = 0;
 197         unsigned long rate_time;
 198         struct thread_data *td, *td2;
 199         struct timeval now;
 200         uint64_t group_bw = 0, group_iops = 0;
 201         uint64_t td_iops, td_bytes;
 202         bool ret;
 203
 204         prev_groupid = -1;
 205         for_each_td(td, i) {
 206                 struct steadystate_data *ss = &td->ss;
 207
 208                 if (!ss->dur || td->runstate <= TD_SETTING_UP ||
 209                     td->runstate >= TD_EXITED || !ss->state ||
 210                     ss->state & __FIO_SS_ATTAINED)
 211                         continue;
 212
 213                 td_iops = 0;
 214                 td_bytes = 0;
 215                 if (!td->o.group_reporting ||
 216                     (td->o.group_reporting && td->groupid != prev_groupid)) {
 217                         group_bw = 0;
 218                         group_iops = 0;
 219                         group_ramp_time_over = 0;
 220                 }
 221                 prev_groupid = td->groupid;
 222
 223                 fio_gettime(&now, NULL);
 224                 if (ss->ramp_time && !(ss->state & __FIO_SS_RAMP_OVER)) {
 225                         /*
 226                          * Begin recording data one second after ss->ramp_time
 227                          * has elapsed
 228                          */
 229                         if (utime_since(&td->epoch, &now) >= (ss->ramp_time + 1000000L))
 230                                 ss->state |= __FIO_SS_RAMP_OVER;
 231                 }
 232
 233                 td_io_u_lock(td);
 234                 for (ddir = 0; ddir < DDIR_RWDIR_CNT; ddir++) {
 235                         td_iops += td->io_blocks[ddir];
 236                         td_bytes += td->io_bytes[ddir];
 237                 }
 238                 td_io_u_unlock(td);
 239
 240                 rate_time = mtime_since(&ss->prev_time, &now);
 241                 memcpy(&ss->prev_time, &now, sizeof(now));
 242
 243                 /*
 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
 248                  * is done.
 249                  */
 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;
 254                 }
 255                 ss->prev_iops = td_iops;
 256                 ss->prev_bytes = td_bytes;
 257
 258                 if (td->o.group_reporting && !(ss->state & __FIO_SS_DATA))
 259                         continue;
 260
 261                 /*
 262                  * Don't begin checking criterion until ss->ramp_time is over
 263                  * for at least one thread in group
 264                  */
 265                 if (!group_ramp_time_over)
 266                         continue;
 267
 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,
 274                                         ss->head, ss->tail);
 275
 276                 if (ss->state & __FIO_SS_SLOPE)
 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) {
 285                                                 td2->ss.state |= __FIO_SS_ATTAINED;
 286                                                 fio_mark_td_terminate(td2);
 287                                         }
 288                                 }
 289                         } else {
 290                                 ss->state |= __FIO_SS_ATTAINED;
 291                                 fio_mark_td_terminate(td);
 292                         }
 293                 }
 294         }
 295 }
 296
 297 int td_steadystate_init(struct thread_data *td)
 298 {
 299         struct steadystate_data *ss = &td->ss;
 300         struct thread_options *o = &td->o;
 301         struct thread_data *td2;
 302         int j;
 303
 304         memset(ss, 0, sizeof(*ss));
 305
 306         if (o->ss_dur) {
 307                 steadystate_enabled = true;
 308                 o->ss_dur /= 1000000L;
 309
 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
 315                 ss->state = o->ss_state;
 316                 if (!td->ss.ramp_time)
 317                         ss->state |= __FIO_SS_RAMP_OVER;
 318
 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;
 321         }
 322
 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;
 327
 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");
 335                                 return 1;
 336                         }
 337                 }
 338         }
 339
 340         return 0;
 341 }
 342
 343 uint64_t steadystate_bw_mean(struct thread_stat *ts)
 344 {
 345         int i;
 346         uint64_t sum;
 347
 348         for (i = 0, sum = 0; i < ts->ss_dur; i++)
 349                 sum += ts->ss_bw_data[i];
 350
 351         return sum / ts->ss_dur;
 352 }
 353
 354 uint64_t steadystate_iops_mean(struct thread_stat *ts)
 355 {
 356         int i;
 357         uint64_t sum;
 358
 359         for (i = 0, sum = 0; i < ts->ss_dur; i++)
 360                 sum += ts->ss_iops_data[i];
 361
 362         return sum / ts->ss_dur;
 363 }