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                         td->ss.state |= __FIO_SS_DATA;
  42                         continue;
  43                 }
  44
  45                 if (prev_groupid != td->groupid) {
  46                         if (prev_td != NULL) {
  47                                 prev_td->ss.state |= __FIO_SS_DATA;
  48                                 steadystate_alloc(prev_td);
  49                         }
  50                         prev_groupid = td->groupid;
  51                 }
  52                 prev_td = td;
  53         }
  54
  55         if (prev_td != NULL && prev_td->o.group_reporting) {
  56                 prev_td->ss.state |= __FIO_SS_DATA;
  57                 steadystate_alloc(prev_td);
  58         }
  59 }
  60
  61 static bool steadystate_slope(unsigned long iops, unsigned long bw,
  62                               struct thread_data *td)
  63 {
  64         int i, j;
  65         double result;
  66         struct steadystate_data *ss = &td->ss;
  67         unsigned long new_val;
  68
  69         ss->bw_data[ss->tail] = bw;
  70         ss->iops_data[ss->tail] = iops;
  71
  72         if (ss->state & __FIO_SS_IOPS)
  73                 new_val = iops;
  74         else
  75                 new_val = bw;
  76
  77         if (ss->tail < ss->head || (ss->tail - ss->head == ss->dur - 1)) {
  78                 if (ss->sum_y == 0) {   /* first time through */
  79                         for(i = 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;
  85                                 if (j >= ss->dur)
  86                                         j -= ss->dur;
  87                                 if (ss->state & __FIO_SS_IOPS)
  88                                         ss->sum_xy += i * ss->iops_data[j];
  89                                 else
  90                                         ss->sum_xy += i * ss->bw_data[j];
  91                         }
  92                 } else {                /* easy to update the sums */
  93                         ss->sum_y -= ss->oldest_y;
  94                         ss->sum_y += new_val;
  95                         ss->sum_xy = ss->sum_xy - ss->sum_y + ss->dur * new_val;
  96                 }
  97
  98                 if (ss->state & __FIO_SS_IOPS)
  99                         ss->oldest_y = ss->iops_data[ss->head];
 100                 else
 101                         ss->oldest_y = ss->bw_data[ss->head];
 102
 103                 /*
 104                  * calculate slope as (sum_xy - sum_x * sum_y / n) / (sum_(x^2)
 105                  * - (sum_x)^2 / n) This code assumes that all x values are
 106                  * equally spaced when they are often off by a few milliseconds.
 107                  * This assumption greatly simplifies the calculations.
 108                  */
 109                 ss->slope = (ss->sum_xy - (double) ss->sum_x * ss->sum_y / ss->dur) /
 110                                 (ss->sum_x_sq - (double) ss->sum_x * ss->sum_x / ss->dur);
 111                 if (ss->state & __FIO_SS_PCT)
 112                         ss->criterion = 100.0 * ss->slope / (ss->sum_y / ss->dur);
 113                 else
 114                         ss->criterion = ss->slope;
 115
 116                 dprint(FD_STEADYSTATE, "sum_y: %llu, sum_xy: %llu, slope: %f, "
 117                                         "criterion: %f, limit: %f\n",
 118                                         ss->sum_y, ss->sum_xy, ss->slope,
 119                                         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(unsigned long iops, unsigned long 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->tail < ss->head || (ss->tail - ss->head == ss->dur - 1)) {
 146                 if (ss->sum_y == 0) {   /* first time through */
 147                         for(i = 0; i < ss->dur; i++)
 148                                 if (ss->state & __FIO_SS_IOPS)
 149                                         ss->sum_y += ss->iops_data[i];
 150                                 else
 151                                         ss->sum_y += ss->bw_data[i];
 152                 } else {                /* easy to update the sum */
 153                         ss->sum_y -= ss->oldest_y;
 154                         if (ss->state & __FIO_SS_IOPS)
 155                                 ss->sum_y += ss->iops_data[ss->tail];
 156                         else
 157                                 ss->sum_y += ss->bw_data[ss->tail];
 158                 }
 159
 160                 if (ss->state & __FIO_SS_IOPS)
 161                         ss->oldest_y = ss->iops_data[ss->head];
 162                 else
 163                         ss->oldest_y = ss->bw_data[ss->head];
 164
 165                 mean = (double) ss->sum_y / ss->dur;
 166                 ss->deviation = 0.0;
 167
 168                 for (i = 0; i < ss->dur; i++) {
 169                         if (ss->state & __FIO_SS_IOPS)
 170                                 diff = ss->iops_data[i] - mean;
 171                         else
 172                                 diff = ss->bw_data[i] - mean;
 173                         ss->deviation = max(ss->deviation, diff * (diff < 0.0 ? -1.0 : 1.0));
 174                 }
 175
 176                 if (ss->state & __FIO_SS_PCT)
 177                         ss->criterion = 100.0 * ss->deviation / mean;
 178                 else
 179                         ss->criterion = ss->deviation;
 180
 181                 dprint(FD_STEADYSTATE, "sum_y: %llu, mean: %f, max diff: %f, "
 182                                         "objective: %f, limit: %f\n",
 183                                         ss->sum_y, mean, ss->deviation,
 184                                         ss->criterion, ss->limit);
 185
 186                 if (ss->criterion < ss->limit)
 187                         return true;
 188         }
 189
 190         ss->tail = (ss->tail + 1) % ss->dur;
 191         if (ss->tail <= ss->head)
 192                 ss->head = (ss->head + 1) % ss->dur;
 193
 194         return false;
 195 }
 196
 197 void steadystate_check(void)
 198 {
 199         int i, j, ddir, prev_groupid, group_ramp_time_over = 0;
 200         unsigned long rate_time;
 201         struct thread_data *td, *td2;
 202         struct timeval now;
 203         unsigned long group_bw = 0, group_iops = 0;
 204         unsigned long long td_iops;
 205         unsigned long long td_bytes;
 206         bool ret;
 207
 208         prev_groupid = -1;
 209         for_each_td(td, i) {
 210                 struct steadystate_data *ss = &td->ss;
 211
 212                 if (!ss->dur || td->runstate <= TD_SETTING_UP ||
 213                     td->runstate >= TD_EXITED || (ss->state & __FIO_SS_ATTAINED))
 214                         continue;
 215
 216                 td_iops = 0;
 217                 td_bytes = 0;
 218                 if (!td->o.group_reporting ||
 219                     (td->o.group_reporting && td->groupid != prev_groupid)) {
 220                         group_bw = 0;
 221                         group_iops = 0;
 222                         group_ramp_time_over = 0;
 223                 }
 224                 prev_groupid = td->groupid;
 225
 226                 fio_gettime(&now, NULL);
 227                 if (ss->ramp_time && !(ss->state & __FIO_SS_RAMP_OVER)) {
 228                         /*
 229                          * Begin recording data one second after ss->ramp_time
 230                          * has elapsed
 231                          */
 232                         if (utime_since(&td->epoch, &now) >= (ss->ramp_time + 1000000L))
 233                                 ss->state |= __FIO_SS_RAMP_OVER;
 234                 }
 235
 236                 td_io_u_lock(td);
 237                 for (ddir = DDIR_READ; ddir < DDIR_RWDIR_CNT; ddir++) {
 238                         td_iops += td->io_blocks[ddir];
 239                         td_bytes += td->io_bytes[ddir];
 240                 }
 241                 td_io_u_unlock(td);
 242
 243                 rate_time = mtime_since(&ss->prev_time, &now);
 244                 memcpy(&ss->prev_time, &now, sizeof(now));
 245
 246                 /*
 247                  * Begin monitoring when job starts but don't actually use
 248                  * data in checking stopping criterion until ss->ramp_time is
 249                  * over. This ensures that we will have a sane value in
 250                  * prev_iops/bw the first time through after ss->ramp_time
 251                  * is done.
 252                  */
 253                 if (ss->state & __FIO_SS_RAMP_OVER) {
 254                         group_bw += 1000 * (td_bytes - ss->prev_bytes) / rate_time;
 255                         group_iops += 1000 * (td_iops - ss->prev_iops) / rate_time;
 256                         ++group_ramp_time_over;
 257                 }
 258                 ss->prev_iops = td_iops;
 259                 ss->prev_bytes = td_bytes;
 260
 261                 if (td->o.group_reporting && !(ss->state & __FIO_SS_DATA))
 262                         continue;
 263
 264                 /*
 265                  * Don't begin checking criterion until ss->ramp_time is over
 266                  * for at least one thread in group
 267                  */
 268                 if (!group_ramp_time_over)
 269                         continue;
 270
 271                 dprint(FD_STEADYSTATE, "steadystate_check() thread: %d, "
 272                                         "groupid: %u, rate_msec: %ld, "
 273                                         "iops: %lu, bw: %lu, head: %d, tail: %d\n",
 274                                         i, td->groupid, rate_time, group_iops,
 275                                         group_bw, ss->head, ss->tail);
 276
 277                 if (td->o.ss & __FIO_SS_SLOPE)
 278                         ret = steadystate_slope(group_iops, group_bw, td);
 279                 else
 280                         ret = steadystate_deviation(group_iops, group_bw, td);
 281
 282                 if (ret) {
 283                         if (td->o.group_reporting) {
 284                                 for_each_td(td2, j) {
 285                                         if (td2->groupid == td->groupid) {
 286                                                 td2->ss.state |= __FIO_SS_ATTAINED;
 287                                                 fio_mark_td_terminate(td2);
 288                                         }
 289                                 }
 290                         } else {
 291                                 ss->state |= __FIO_SS_ATTAINED;
 292                                 fio_mark_td_terminate(td);
 293                         }
 294                 }
 295         }
 296 }
 297
 298 int td_steadystate_init(struct thread_data *td)
 299 {
 300         struct steadystate_data *ss = &td->ss;
 301         struct thread_options *o = &td->o;
 302         struct thread_data *td2;
 303         int j;
 304
 305         memset(ss, 0, sizeof(*ss));
 306
 307         if (o->ss_dur) {
 308                 steadystate_enabled = true;
 309                 o->ss_dur /= 1000000L;
 310
 311                 /* put all steady state info in one place */
 312                 ss->dur = o->ss_dur;
 313                 ss->limit = o->ss_limit.u.f;
 314                 ss->ramp_time = o->ss_ramp_time;
 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->state != ss->state ||
 335                             ss2->sum_x != ss->sum_x ||
 336                             ss2->sum_x_sq != ss->sum_x_sq) {
 337                                 td_verror(td, EINVAL, "job rejected: steadystate options must be consistent within reporting groups");
 338                                 return 1;
 339                         }
 340                 }
 341         }
 342
 343         return 0;
 344 }
 345
 346 unsigned long long steadystate_bw_mean(struct steadystate_data *ss)
 347 {
 348         int i;
 349         unsigned long long sum;
 350
 351         for (i = 0, sum = 0; i < ss->dur; i++)
 352                 sum += ss->bw_data[i];
 353
 354         return sum / ss->dur;
 355 }
 356
 357 unsigned long long steadystate_iops_mean(struct steadystate_data *ss)
 358 {
 359         int i;
 360         unsigned long long sum;
 361
 362         for (i = 0, sum = 0; i < ss->dur; i++)
 363                 sum += ss->iops_data[i];
 364
 365         return sum / ss->dur;
 366 }