steadystate.c

   1 #include <stdlib.h>
   2
   3 #include "fio.h"
   4 #include "steadystate.h"
   5
   6 bool steadystate_enabled = false;
   7
   8 void steadystate_free(struct thread_data *td)
   9 {
  10         free(td->ss.iops_data);
  11         free(td->ss.bw_data);
  12         td->ss.iops_data = NULL;
  13         td->ss.bw_data = NULL;
  14 }
  15
  16 static void steadystate_alloc(struct thread_data *td)
  17 {
  18         td->ss.bw_data = calloc(td->ss.dur, sizeof(uint64_t));
  19         td->ss.iops_data = calloc(td->ss.dur, sizeof(uint64_t));
  20
  21         td->ss.state |= FIO_SS_DATA;
  22 }
  23
  24 void steadystate_setup(void)
  25 {
  26         struct thread_data *td, *prev_td;
  27         int i, prev_groupid;
  28
  29         if (!steadystate_enabled)
  30                 return;
  31
  32         /*
  33          * if group reporting is enabled, identify the last td
  34          * for each group and use it for storing steady state
  35          * data
  36          */
  37         prev_groupid = -1;
  38         prev_td = NULL;
  39         for_each_td(td, i) {
  40                 if (!td->ss.dur)
  41                         continue;
  42
  43                 if (!td->o.group_reporting) {
  44                         steadystate_alloc(td);
  45                         continue;
  46                 }
  47
  48                 if (prev_groupid != td->groupid) {
  49                         if (prev_td)
  50                                 steadystate_alloc(prev_td);
  51                         prev_groupid = td->groupid;
  52                 }
  53                 prev_td = td;
  54         }
  55
  56         if (prev_td && prev_td->o.group_reporting)
  57                 steadystate_alloc(prev_td);
  58 }
  59
  60 static bool steadystate_slope(uint64_t iops, uint64_t bw,
  61                               struct thread_data *td)
  62 {
  63         int i, j;
  64         double result;
  65         struct steadystate_data *ss = &td->ss;
  66         uint64_t 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->state & FIO_SS_BUFFER_FULL || ss->tail - ss->head == ss->dur - 1) {
  77                 if (!(ss->state & FIO_SS_BUFFER_FULL)) {
  78                         /* first time through */
  79                         for(i = 0, ss->sum_y = 0; i < ss->dur; i++) {
  80                                 if (ss->state & FIO_SS_IOPS)
  81                                         ss->sum_y += ss->iops_data[i];
  82                                 else
  83                                         ss->sum_y += ss->bw_data[i];
  84                                 j = (ss->head + i) % ss->dur;
  85                                 if (ss->state & FIO_SS_IOPS)
  86                                         ss->sum_xy += i * ss->iops_data[j];
  87                                 else
  88                                         ss->sum_xy += i * ss->bw_data[j];
  89                         }
  90                         ss->state |= FIO_SS_BUFFER_FULL;
  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->state & FIO_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                                         (unsigned long long) ss->sum_y,
 118                                         (unsigned long long) ss->sum_xy,
 119                                         ss->slope, ss->criterion, ss->limit);
 120
 121                 result = ss->criterion * (ss->criterion < 0.0 ? -1.0 : 1.0);
 122                 if (result < ss->limit)
 123                         return true;
 124         }
 125
 126         ss->tail = (ss->tail + 1) % ss->dur;
 127         if (ss->tail <= ss->head)
 128                 ss->head = (ss->head + 1) % ss->dur;
 129
 130         return false;
 131 }
 132
 133 static bool steadystate_deviation(uint64_t iops, uint64_t bw,
 134                                   struct thread_data *td)
 135 {
 136         int i;
 137         double diff;
 138         double mean;
 139
 140         struct steadystate_data *ss = &td->ss;
 141
 142         ss->bw_data[ss->tail] = bw;
 143         ss->iops_data[ss->tail] = iops;
 144
 145         if (ss->state & FIO_SS_BUFFER_FULL || ss->tail - ss->head == ss->dur - 1) {
 146                 if (!(ss->state & FIO_SS_BUFFER_FULL)) {
 147                         /* first time through */
 148                         for(i = 0, ss->sum_y = 0; i < ss->dur; i++)
 149                                 if (ss->state & FIO_SS_IOPS)
 150                                         ss->sum_y += ss->iops_data[i];
 151                                 else
 152                                         ss->sum_y += ss->bw_data[i];
 153                         ss->state |= FIO_SS_BUFFER_FULL;
 154                 } else {                /* easy to update the sum */
 155                         ss->sum_y -= ss->oldest_y;
 156                         if (ss->state & FIO_SS_IOPS)
 157                                 ss->sum_y += ss->iops_data[ss->tail];
 158                         else
 159                                 ss->sum_y += ss->bw_data[ss->tail];
 160                 }
 161
 162                 if (ss->state & FIO_SS_IOPS)
 163                         ss->oldest_y = ss->iops_data[ss->head];
 164                 else
 165                         ss->oldest_y = ss->bw_data[ss->head];
 166
 167                 mean = (double) ss->sum_y / ss->dur;
 168                 ss->deviation = 0.0;
 169
 170                 for (i = 0; i < ss->dur; i++) {
 171                         if (ss->state & FIO_SS_IOPS)
 172                                 diff = ss->iops_data[i] - mean;
 173                         else
 174                                 diff = ss->bw_data[i] - mean;
 175                         ss->deviation = max(ss->deviation, diff * (diff < 0.0 ? -1.0 : 1.0));
 176                 }
 177
 178                 if (ss->state & FIO_SS_PCT)
 179                         ss->criterion = 100.0 * ss->deviation / mean;
 180                 else
 181                         ss->criterion = ss->deviation;
 182
 183                 dprint(FD_STEADYSTATE, "sum_y: %llu, mean: %f, max diff: %f, "
 184                                         "objective: %f, limit: %f\n",
 185                                         (unsigned long long) ss->sum_y, mean,
 186                                         ss->deviation, ss->criterion, ss->limit);
 187
 188                 if (ss->criterion < ss->limit)
 189                         return true;
 190         }
 191
 192         ss->tail = (ss->tail + 1) % ss->dur;
 193         if (ss->tail <= ss->head)
 194                 ss->head = (ss->head + 1) % ss->dur;
 195
 196         return false;
 197 }
 198
 199 void steadystate_check(void)
 200 {
 201         int i, j, ddir, prev_groupid, group_ramp_time_over = 0;
 202         unsigned long rate_time;
 203         struct thread_data *td, *td2;
 204         struct timespec now;
 205         uint64_t group_bw = 0, group_iops = 0;
 206         uint64_t td_iops, td_bytes;
 207         bool ret;
 208
 209         prev_groupid = -1;
 210         for_each_td(td, i) {
 211                 const bool needs_lock = td_async_processing(td);
 212                 struct steadystate_data *ss = &td->ss;
 213
 214                 if (!ss->dur || td->runstate <= TD_SETTING_UP ||
 215                     td->runstate >= TD_EXITED || !ss->state ||
 216                     ss->state & FIO_SS_ATTAINED)
 217                         continue;
 218
 219                 td_iops = 0;
 220                 td_bytes = 0;
 221                 if (!td->o.group_reporting ||
 222                     (td->o.group_reporting && td->groupid != prev_groupid)) {
 223                         group_bw = 0;
 224                         group_iops = 0;
 225                         group_ramp_time_over = 0;
 226                 }
 227                 prev_groupid = td->groupid;
 228
 229                 fio_gettime(&now, NULL);
 230                 if (ss->ramp_time && !(ss->state & FIO_SS_RAMP_OVER)) {
 231                         /*
 232                          * Begin recording data one second after ss->ramp_time
 233                          * has elapsed
 234                          */
 235                         if (utime_since(&td->epoch, &now) >= (ss->ramp_time + 1000000L))
 236                                 ss->state |= FIO_SS_RAMP_OVER;
 237                 }
 238
 239                 if (needs_lock)
 240                         __td_io_u_lock(td);
 241
 242                 for (ddir = 0; ddir < DDIR_RWDIR_CNT; ddir++) {
 243                         td_iops += td->io_blocks[ddir];
 244                         td_bytes += td->io_bytes[ddir];
 245                 }
 246
 247                 if (needs_lock)
 248                         __td_io_u_unlock(td);
 249
 250                 rate_time = mtime_since(&ss->prev_time, &now);
 251                 memcpy(&ss->prev_time, &now, sizeof(now));
 252
 253                 /*
 254                  * Begin monitoring when job starts but don't actually use
 255                  * data in checking stopping criterion until ss->ramp_time is
 256                  * over. This ensures that we will have a sane value in
 257                  * prev_iops/bw the first time through after ss->ramp_time
 258                  * is done.
 259                  */
 260                 if (ss->state & FIO_SS_RAMP_OVER) {
 261                         group_bw += 1000 * (td_bytes - ss->prev_bytes) / rate_time;
 262                         group_iops += 1000 * (td_iops - ss->prev_iops) / rate_time;
 263                         ++group_ramp_time_over;
 264                 }
 265                 ss->prev_iops = td_iops;
 266                 ss->prev_bytes = td_bytes;
 267
 268                 if (td->o.group_reporting && !(ss->state & FIO_SS_DATA))
 269                         continue;
 270
 271                 /*
 272                  * Don't begin checking criterion until ss->ramp_time is over
 273                  * for at least one thread in group
 274                  */
 275                 if (!group_ramp_time_over)
 276                         continue;
 277
 278                 dprint(FD_STEADYSTATE, "steadystate_check() thread: %d, "
 279                                         "groupid: %u, rate_msec: %ld, "
 280                                         "iops: %llu, bw: %llu, head: %d, tail: %d\n",
 281                                         i, td->groupid, rate_time,
 282                                         (unsigned long long) group_iops,
 283                                         (unsigned long long) group_bw,
 284                                         ss->head, ss->tail);
 285
 286                 if (ss->state & FIO_SS_SLOPE)
 287                         ret = steadystate_slope(group_iops, group_bw, td);
 288                 else
 289                         ret = steadystate_deviation(group_iops, group_bw, td);
 290
 291                 if (ret) {
 292                         if (td->o.group_reporting) {
 293                                 for_each_td(td2, j) {
 294                                         if (td2->groupid == td->groupid) {
 295                                                 td2->ss.state |= FIO_SS_ATTAINED;
 296                                                 fio_mark_td_terminate(td2);
 297                                         }
 298                                 }
 299                         } else {
 300                                 ss->state |= FIO_SS_ATTAINED;
 301                                 fio_mark_td_terminate(td);
 302                         }
 303                 }
 304         }
 305 }
 306
 307 int td_steadystate_init(struct thread_data *td)
 308 {
 309         struct steadystate_data *ss = &td->ss;
 310         struct thread_options *o = &td->o;
 311         struct thread_data *td2;
 312         int j;
 313
 314         memset(ss, 0, sizeof(*ss));
 315
 316         if (o->ss_dur) {
 317                 steadystate_enabled = true;
 318                 o->ss_dur /= 1000000L;
 319
 320                 /* put all steady state info in one place */
 321                 ss->dur = o->ss_dur;
 322                 ss->limit = o->ss_limit.u.f;
 323                 ss->ramp_time = o->ss_ramp_time;
 324
 325                 ss->state = o->ss_state;
 326                 if (!td->ss.ramp_time)
 327                         ss->state |= FIO_SS_RAMP_OVER;
 328
 329                 ss->sum_x = o->ss_dur * (o->ss_dur - 1) / 2;
 330                 ss->sum_x_sq = (o->ss_dur - 1) * (o->ss_dur) * (2*o->ss_dur - 1) / 6;
 331         }
 332
 333         /* make sure that ss options are consistent within reporting group */
 334         for_each_td(td2, j) {
 335                 if (td2->groupid == td->groupid) {
 336                         struct steadystate_data *ss2 = &td2->ss;
 337
 338                         if (ss2->dur != ss->dur ||
 339                             ss2->limit != ss->limit ||
 340                             ss2->ramp_time != ss->ramp_time ||
 341                             ss2->state != ss->state ||
 342                             ss2->sum_x != ss->sum_x ||
 343                             ss2->sum_x_sq != ss->sum_x_sq) {
 344                                 td_verror(td, EINVAL, "job rejected: steadystate options must be consistent within reporting groups");
 345                                 return 1;
 346                         }
 347                 }
 348         }
 349
 350         return 0;
 351 }
 352
 353 uint64_t steadystate_bw_mean(struct thread_stat *ts)
 354 {
 355         int i;
 356         uint64_t sum;
 357
 358         if (!ts->ss_dur)
 359                 return 0;
 360
 361         for (i = 0, sum = 0; i < ts->ss_dur; i++)
 362                 sum += ts->ss_bw_data[i];
 363
 364         return sum / ts->ss_dur;
 365 }
 366
 367 uint64_t steadystate_iops_mean(struct thread_stat *ts)
 368 {
 369         int i;
 370         uint64_t sum;
 371
 372         if (!ts->ss_dur)
 373                 return 0;
 374
 375         for (i = 0, sum = 0; i < ts->ss_dur; i++)
 376                 sum += ts->ss_iops_data[i];
 377
 378         return sum / ts->ss_dur;
 379 }