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         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
  20 void steadystate_setup(void)
  21 {
  22         int i, prev_groupid;
  23         struct thread_data *td, *prev_td;
  24
  25         if (!steadystate_enabled)
  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) {
  36                 if (td->ts.ss == NULL)
  37                         continue;
  38
  39                 if (!td->o.group_reporting) {
  40                         steadystate_alloc(td);
  41                         continue;
  42                 }
  43
  44                 if (prev_groupid != td->groupid) {
  45                         if (prev_td != NULL) {
  46                                 prev_td->ss.state |= __FIO_SS_DATA;
  47                                 steadystate_alloc(prev_td);
  48                         }
  49                         prev_groupid = td->groupid;
  50                 }
  51                 prev_td = td;
  52         }
  53
  54         if (prev_td != NULL && prev_td->o.group_reporting) {
  55                 prev_td->ss.state |= __FIO_SS_DATA;
  56                 steadystate_alloc(prev_td);
  57         }
  58 }
  59
  60 static bool steadystate_slope(unsigned long iops, unsigned long bw,
  61                               struct thread_data *td)
  62 {
  63         int i, j;
  64         double result;
  65         struct steadystate_data *ss = &td->ss;
  66         unsigned long new_val;
  67
  68         ss->bw_data[ss->tail] = bw;
  69         ss->iops_data[ss->tail] = iops;
  70
  71         if (ss->state & __FIO_SS_IOPS)
  72                 new_val = iops;
  73         else
  74                 new_val = bw;
  75
  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++) {
  79                                 if (ss->state & __FIO_SS_IOPS)
  80                                         ss->sum_y += ss->iops_data[i];
  81                                 else
  82                                         ss->sum_y += ss->bw_data[i];
  83                                 j = ss->head + i;
  84                                 if (j >= ss->dur)
  85                                         j -= ss->dur;
  86                                 if (ss->state & __FIO_SS_IOPS)
  87                                         ss->sum_xy += i * ss->iops_data[j];
  88                                 else
  89                                         ss->sum_xy += i * ss->bw_data[j];
  90                         }
  91                 } else {                /* easy to update the sums */
  92                         ss->sum_y -= ss->oldest_y;
  93                         ss->sum_y += new_val;
  94                         ss->sum_xy = ss->sum_xy - ss->sum_y + ss->dur * new_val;
  95                 }
  96
  97                 if (ss->state & __FIO_SS_IOPS)
  98                         ss->oldest_y = ss->iops_data[ss->head];
  99                 else
 100                         ss->oldest_y = ss->bw_data[ss->head];
 101
 102                 /*
 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.
 107                  */
 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;
 114
 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);
 119
 120                 result = ss->criterion * (ss->criterion < 0.0 ? -1.0 : 1.0);
 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;
 128
 129         return false;
 130 }
 131
 132 static bool steadystate_deviation(unsigned long iops, unsigned long bw,
 133                                   struct thread_data *td)
 134 {
 135         int i;
 136         double diff;
 137         double mean;
 138
 139         struct steadystate_data *ss = &td->ss;
 140
 141         ss->bw_data[ss->tail] = bw;
 142         ss->iops_data[ss->tail] = iops;
 143
 144         if (ss->tail < ss->head || (ss->tail - ss->head == ss->dur - 1)) {
 145                 if (ss->sum_y == 0) {   /* first time through */
 146                         for(i = 0; i < ss->dur; i++)
 147                                 if (ss->state & __FIO_SS_IOPS)
 148                                         ss->sum_y += ss->iops_data[i];
 149                                 else
 150                                         ss->sum_y += ss->bw_data[i];
 151                 } else {                /* easy to update the sum */
 152                         ss->sum_y -= ss->oldest_y;
 153                         if (ss->state & __FIO_SS_IOPS)
 154                                 ss->sum_y += ss->iops_data[ss->tail];
 155                         else
 156                                 ss->sum_y += ss->bw_data[ss->tail];
 157                 }
 158
 159                 if (ss->state & __FIO_SS_IOPS)
 160                         ss->oldest_y = ss->iops_data[ss->head];
 161                 else
 162                         ss->oldest_y = ss->bw_data[ss->head];
 163
 164                 mean = (double) ss->sum_y / ss->dur;
 165                 ss->deviation = 0.0;
 166
 167                 for (i = 0; i < ss->dur; i++) {
 168                         if (ss->state & __FIO_SS_IOPS)
 169                                 diff = ss->iops_data[i] - mean;
 170                         else
 171                                 diff = ss->bw_data[i] - mean;
 172                         ss->deviation = max(ss->deviation, diff * (diff < 0.0 ? -1.0 : 1.0));
 173                 }
 174
 175                 if (ss->pct)
 176                         ss->criterion = 100.0 * ss->deviation / mean;
 177                 else
 178                         ss->criterion = ss->deviation;
 179
 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);
 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;
 192
 193         return false;
 194 }
 195
 196 void 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
 211                 if (!ss->dur || td->runstate <= TD_SETTING_UP ||
 212                     td->runstate >= TD_EXITED || (ss->state & __FIO_SS_ATTAINED))
 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);
 226                 if (ss->ramp_time && !(ss->state & __FIO_SS_RAMP_OVER)) {
 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))
 232                                 ss->state |= __FIO_SS_RAMP_OVER;
 233                 }
 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                  */
 252                 if (ss->state & __FIO_SS_RAMP_OVER) {
 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
 260                 if (td->o.group_reporting && !(ss->state & __FIO_SS_DATA))
 261                         continue;
 262
 263                 /*
 264                  * Don't begin checking criterion until ss->ramp_time is over
 265                  * for at least one thread in group
 266                  */
 267                 if (!group_ramp_time_over)
 268                         continue;
 269
 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);
 275
 276                 if (td->o.ss & __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                 ss->pct = o->ss_pct;
 315
 316                 ss->state = o->ss;
 317                 if (!td->ss.ramp_time)
 318                         ss->state |= __FIO_SS_RAMP_OVER;
 319
 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         }
 325
 326         /* make sure that ss options are consistent within reporting group */
 327         for_each_td(td2, j) {
 328                 if (td2->groupid == td->groupid) {
 329                         struct steadystate_data *ss2 = &td2->ss;
 330
 331                         if (ss2->dur != ss->dur ||
 332                             ss2->limit != ss->limit ||
 333                             ss2->ramp_time != ss->ramp_time ||
 334                             ss2->pct != ss->pct ||
 335                             ss2->state != ss->state ||
 336                             ss2->sum_x != ss->sum_x ||
 337                             ss2->sum_x_sq != ss->sum_x_sq) {
 338                                 td_verror(td, EINVAL, "job rejected: steadystate options must be consistent within reporting groups");
 339                                 return 1;
 340                         }
 341                 }
 342         }
 343
 344         return 0;
 345 }