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