blktrace.c

   1 /*
   2  * blktrace support code for fio
   3  */
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <sys/stat.h>
   7 #include <dirent.h>
   8
   9 #include "flist.h"
  10 #include "fio.h"
  11 #include "blktrace_api.h"
  12 #include "lib/linux-dev-lookup.h"
  13
  14 #define TRACE_FIFO_SIZE 8192
  15
  16 /*
  17  * fifo refill frontend, to avoid reading data in trace sized bites
  18  */
  19 static int refill_fifo(struct thread_data *td, struct fifo *fifo, int fd)
  20 {
  21         char buf[TRACE_FIFO_SIZE];
  22         unsigned int total;
  23         int ret;
  24
  25         total = sizeof(buf);
  26         if (total > fifo_room(fifo))
  27                 total = fifo_room(fifo);
  28
  29         ret = read(fd, buf, total);
  30         if (ret < 0) {
  31                 td_verror(td, errno, "read blktrace file");
  32                 return -1;
  33         }
  34
  35         if (ret > 0)
  36                 ret = fifo_put(fifo, buf, ret);
  37
  38         dprint(FD_BLKTRACE, "refill: filled %d bytes\n", ret);
  39         return ret;
  40 }
  41
  42 /*
  43  * Retrieve 'len' bytes from the fifo, refilling if necessary.
  44  */
  45 static int trace_fifo_get(struct thread_data *td, struct fifo *fifo, int fd,
  46                           void *buf, unsigned int len)
  47 {
  48         if (fifo_len(fifo) < len) {
  49                 int ret = refill_fifo(td, fifo, fd);
  50
  51                 if (ret < 0)
  52                         return ret;
  53         }
  54
  55         return fifo_get(fifo, buf, len);
  56 }
  57
  58 /*
  59  * Just discard the pdu by seeking past it.
  60  */
  61 static int discard_pdu(struct thread_data *td, struct fifo *fifo, int fd,
  62                        struct blk_io_trace *t)
  63 {
  64         if (t->pdu_len == 0)
  65                 return 0;
  66
  67         dprint(FD_BLKTRACE, "discard pdu len %u\n", t->pdu_len);
  68         return trace_fifo_get(td, fifo, fd, NULL, t->pdu_len);
  69 }
  70
  71 /*
  72  * Check if this is a blktrace binary data file. We read a single trace
  73  * into memory and check for the magic signature.
  74  */
  75 int is_blktrace(const char *filename, int *need_swap)
  76 {
  77         struct blk_io_trace t;
  78         int fd, ret;
  79
  80         fd = open(filename, O_RDONLY);
  81         if (fd < 0)
  82                 return 0;
  83
  84         ret = read(fd, &t, sizeof(t));
  85         close(fd);
  86
  87         if (ret < 0) {
  88                 perror("read blktrace");
  89                 return 0;
  90         } else if (ret != sizeof(t)) {
  91                 log_err("fio: short read on blktrace file\n");
  92                 return 0;
  93         }
  94
  95         if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
  96                 *need_swap = 0;
  97                 return 1;
  98         }
  99
 100         /*
 101          * Maybe it needs to be endian swapped...
 102          */
 103         t.magic = fio_swap32(t.magic);
 104         if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
 105                 *need_swap = 1;
 106                 return 1;
 107         }
 108
 109         return 0;
 110 }
 111
 112 #define FMINORBITS      20
 113 #define FMINORMASK      ((1U << FMINORBITS) - 1)
 114 #define FMAJOR(dev)     ((unsigned int) ((dev) >> FMINORBITS))
 115 #define FMINOR(dev)     ((unsigned int) ((dev) & FMINORMASK))
 116
 117 static void trace_add_open_close_event(struct thread_data *td, int fileno, enum file_log_act action)
 118 {
 119         struct io_piece *ipo;
 120
 121         ipo = calloc(1, sizeof(*ipo));
 122         init_ipo(ipo);
 123
 124         ipo->ddir = DDIR_INVAL;
 125         ipo->fileno = fileno;
 126         ipo->file_action = action;
 127         flist_add_tail(&ipo->list, &td->io_log_list);
 128 }
 129
 130 static int trace_add_file(struct thread_data *td, __u32 device)
 131 {
 132         static unsigned int last_maj, last_min, last_fileno;
 133         unsigned int maj = FMAJOR(device);
 134         unsigned int min = FMINOR(device);
 135         struct fio_file *f;
 136         char dev[256];
 137         unsigned int i;
 138
 139         if (last_maj == maj && last_min == min)
 140                 return last_fileno;
 141
 142         last_maj = maj;
 143         last_min = min;
 144
 145         /*
 146          * check for this file in our list
 147          */
 148         for_each_file(td, f, i)
 149                 if (f->major == maj && f->minor == min) {
 150                         last_fileno = f->fileno;
 151                         return last_fileno;
 152                 }
 153
 154         strcpy(dev, "/dev");
 155         if (blktrace_lookup_device(td->o.replay_redirect, dev, maj, min)) {
 156                 int fileno;
 157
 158                 if (td->o.replay_redirect)
 159                         dprint(FD_BLKTRACE, "device lookup: %d/%d\n overridden"
 160                                         " with: %s\n", maj, min,
 161                                         td->o.replay_redirect);
 162                 else
 163                         dprint(FD_BLKTRACE, "device lookup: %d/%d\n", maj, min);
 164
 165                 dprint(FD_BLKTRACE, "add devices %s\n", dev);
 166                 fileno = add_file_exclusive(td, dev);
 167                 td->o.open_files++;
 168                 td->files[fileno]->major = maj;
 169                 td->files[fileno]->minor = min;
 170                 trace_add_open_close_event(td, fileno, FIO_LOG_OPEN_FILE);
 171                 last_fileno = fileno;
 172         }
 173
 174         return last_fileno;
 175 }
 176
 177 /*
 178  * Store blk_io_trace data in an ipo for later retrieval.
 179  */
 180 static void store_ipo(struct thread_data *td, unsigned long long offset,
 181                       unsigned int bytes, int rw, unsigned long long ttime,
 182                       int fileno)
 183 {
 184         struct io_piece *ipo = malloc(sizeof(*ipo));
 185
 186         init_ipo(ipo);
 187
 188         /*
 189          * the 512 is wrong here, it should be the hardware sector size...
 190          */
 191         ipo->offset = offset * 512;
 192         ipo->len = bytes;
 193         ipo->delay = ttime / 1000;
 194         if (rw)
 195                 ipo->ddir = DDIR_WRITE;
 196         else
 197                 ipo->ddir = DDIR_READ;
 198         ipo->fileno = fileno;
 199
 200         dprint(FD_BLKTRACE, "store ddir=%d, off=%llu, len=%lu, delay=%lu\n",
 201                                                         ipo->ddir, ipo->offset,
 202                                                         ipo->len, ipo->delay);
 203         queue_io_piece(td, ipo);
 204 }
 205
 206 static void handle_trace_notify(struct blk_io_trace *t)
 207 {
 208         switch (t->action) {
 209         case BLK_TN_PROCESS:
 210                 dprint(FD_BLKTRACE, "got process notify: %x, %d\n",
 211                                 t->action, t->pid);
 212                 break;
 213         case BLK_TN_TIMESTAMP:
 214                 dprint(FD_BLKTRACE, "got timestamp notify: %x, %d\n",
 215                                 t->action, t->pid);
 216                 break;
 217         case BLK_TN_MESSAGE:
 218                 break;
 219         default:
 220                 dprint(FD_BLKTRACE, "unknown trace act %x\n", t->action);
 221                 break;
 222         }
 223 }
 224
 225 static void handle_trace_discard(struct thread_data *td,
 226                                  struct blk_io_trace *t,
 227                                  unsigned long long ttime,
 228                                  unsigned long *ios, unsigned int *bs)
 229 {
 230         struct io_piece *ipo = malloc(sizeof(*ipo));
 231         int fileno;
 232
 233         init_ipo(ipo);
 234         fileno = trace_add_file(td, t->device);
 235
 236         ios[DDIR_TRIM]++;
 237         if (t->bytes > bs[DDIR_TRIM])
 238                 bs[DDIR_TRIM] = t->bytes;
 239
 240         td->o.size += t->bytes;
 241
 242         memset(ipo, 0, sizeof(*ipo));
 243         INIT_FLIST_HEAD(&ipo->list);
 244
 245         /*
 246          * the 512 is wrong here, it should be the hardware sector size...
 247          */
 248         ipo->offset = t->sector * 512;
 249         ipo->len = t->bytes;
 250         ipo->delay = ttime / 1000;
 251         ipo->ddir = DDIR_TRIM;
 252         ipo->fileno = fileno;
 253
 254         dprint(FD_BLKTRACE, "store discard, off=%llu, len=%lu, delay=%lu\n",
 255                                                         ipo->offset, ipo->len,
 256                                                         ipo->delay);
 257         queue_io_piece(td, ipo);
 258 }
 259
 260 static void handle_trace_fs(struct thread_data *td, struct blk_io_trace *t,
 261                             unsigned long long ttime, unsigned long *ios,
 262                             unsigned int *bs)
 263 {
 264         int rw;
 265         int fileno;
 266
 267         fileno = trace_add_file(td, t->device);
 268
 269         rw = (t->action & BLK_TC_ACT(BLK_TC_WRITE)) != 0;
 270
 271         if (t->bytes > bs[rw])
 272                 bs[rw] = t->bytes;
 273
 274         ios[rw]++;
 275         td->o.size += t->bytes;
 276         store_ipo(td, t->sector, t->bytes, rw, ttime, fileno);
 277 }
 278
 279 /*
 280  * We only care for queue traces, most of the others are side effects
 281  * due to internal workings of the block layer.
 282  */
 283 static void handle_trace(struct thread_data *td, struct blk_io_trace *t,
 284                          unsigned long *ios, unsigned int *bs)
 285 {
 286         static unsigned long long last_ttime;
 287         unsigned long long delay;
 288
 289         if ((t->action & 0xffff) != __BLK_TA_QUEUE)
 290                 return;
 291
 292         if (!(t->action & BLK_TC_ACT(BLK_TC_NOTIFY))) {
 293                 if (!last_ttime || td->o.no_stall) {
 294                         last_ttime = t->time;
 295                         delay = 0;
 296                 } else {
 297                         delay = t->time - last_ttime;
 298                         last_ttime = t->time;
 299                 }
 300         }
 301
 302         if (t->action & BLK_TC_ACT(BLK_TC_NOTIFY))
 303                 handle_trace_notify(t);
 304         else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
 305                 handle_trace_discard(td, t, delay, ios, bs);
 306         else
 307                 handle_trace_fs(td, t, delay, ios, bs);
 308 }
 309
 310 static void byteswap_trace(struct blk_io_trace *t)
 311 {
 312         t->magic = fio_swap32(t->magic);
 313         t->sequence = fio_swap32(t->sequence);
 314         t->time = fio_swap64(t->time);
 315         t->sector = fio_swap64(t->sector);
 316         t->bytes = fio_swap32(t->bytes);
 317         t->action = fio_swap32(t->action);
 318         t->pid = fio_swap32(t->pid);
 319         t->device = fio_swap32(t->device);
 320         t->cpu = fio_swap32(t->cpu);
 321         t->error = fio_swap16(t->error);
 322         t->pdu_len = fio_swap16(t->pdu_len);
 323 }
 324
 325 static int t_is_write(struct blk_io_trace *t)
 326 {
 327         return (t->action & BLK_TC_ACT(BLK_TC_WRITE | BLK_TC_DISCARD)) != 0;
 328 }
 329
 330 static enum fio_ddir t_get_ddir(struct blk_io_trace *t)
 331 {
 332         if (t->action & BLK_TC_ACT(BLK_TC_READ))
 333                 return DDIR_READ;
 334         else if (t->action & BLK_TC_ACT(BLK_TC_WRITE))
 335                 return DDIR_WRITE;
 336         else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
 337                 return DDIR_TRIM;
 338
 339         return DDIR_INVAL;
 340 }
 341
 342 static void depth_inc(struct blk_io_trace *t, int *depth)
 343 {
 344         enum fio_ddir ddir;
 345
 346         ddir = t_get_ddir(t);
 347         if (ddir != DDIR_INVAL)
 348                 depth[ddir]++;
 349 }
 350
 351 static void depth_dec(struct blk_io_trace *t, int *depth)
 352 {
 353         enum fio_ddir ddir;
 354
 355         ddir = t_get_ddir(t);
 356         if (ddir != DDIR_INVAL)
 357                 depth[ddir]--;
 358 }
 359
 360 static void depth_end(struct blk_io_trace *t, int *this_depth, int *depth)
 361 {
 362         enum fio_ddir ddir = DDIR_INVAL;
 363
 364         ddir = t_get_ddir(t);
 365         if (ddir != DDIR_INVAL) {
 366                 depth[ddir] = max(depth[ddir], this_depth[ddir]);
 367                 this_depth[ddir] = 0;
 368         }
 369 }
 370
 371 /*
 372  * Load a blktrace file by reading all the blk_io_trace entries, and storing
 373  * them as io_pieces like the fio text version would do.
 374  */
 375 int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 376 {
 377         struct blk_io_trace t;
 378         unsigned long ios[DDIR_RWDIR_CNT], skipped_writes;
 379         unsigned int rw_bs[DDIR_RWDIR_CNT];
 380         struct fifo *fifo;
 381         int fd, i, old_state;
 382         struct fio_file *f;
 383         int this_depth[DDIR_RWDIR_CNT], depth[DDIR_RWDIR_CNT], max_depth;
 384
 385         fd = open(filename, O_RDONLY);
 386         if (fd < 0) {
 387                 td_verror(td, errno, "open blktrace file");
 388                 return 1;
 389         }
 390
 391         fifo = fifo_alloc(TRACE_FIFO_SIZE);
 392
 393         old_state = td_bump_runstate(td, TD_SETTING_UP);
 394
 395         td->o.size = 0;
 396
 397         for (i = 0; i < DDIR_RWDIR_CNT; i++) {
 398                 ios[i] = 0;
 399                 rw_bs[i] = 0;
 400                 this_depth[i] = 0;
 401                 depth[i] = 0;
 402         }
 403
 404         skipped_writes = 0;
 405         do {
 406                 int ret = trace_fifo_get(td, fifo, fd, &t, sizeof(t));
 407
 408                 if (ret < 0)
 409                         goto err;
 410                 else if (!ret)
 411                         break;
 412                 else if (ret < (int) sizeof(t)) {
 413                         log_err("fio: short fifo get\n");
 414                         break;
 415                 }
 416
 417                 if (need_swap)
 418                         byteswap_trace(&t);
 419
 420                 if ((t.magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) {
 421                         log_err("fio: bad magic in blktrace data: %x\n",
 422                                                                 t.magic);
 423                         goto err;
 424                 }
 425                 if ((t.magic & 0xff) != BLK_IO_TRACE_VERSION) {
 426                         log_err("fio: bad blktrace version %d\n",
 427                                                                 t.magic & 0xff);
 428                         goto err;
 429                 }
 430                 ret = discard_pdu(td, fifo, fd, &t);
 431                 if (ret < 0) {
 432                         td_verror(td, ret, "blktrace lseek");
 433                         goto err;
 434                 } else if (t.pdu_len != ret) {
 435                         log_err("fio: discarded %d of %d\n", ret, t.pdu_len);
 436                         goto err;
 437                 }
 438                 if ((t.action & BLK_TC_ACT(BLK_TC_NOTIFY)) == 0) {
 439                         if ((t.action & 0xffff) == __BLK_TA_QUEUE)
 440                                 depth_inc(&t, this_depth);
 441                         else if (((t.action & 0xffff) == __BLK_TA_BACKMERGE) ||
 442                                 ((t.action & 0xffff) == __BLK_TA_FRONTMERGE))
 443                                 depth_dec(&t, this_depth);
 444                         else if ((t.action & 0xffff) == __BLK_TA_COMPLETE)
 445                                 depth_end(&t, this_depth, depth);
 446
 447                         if (t_is_write(&t) && read_only) {
 448                                 skipped_writes++;
 449                                 continue;
 450                         }
 451                 }
 452
 453                 handle_trace(td, &t, ios, rw_bs);
 454         } while (1);
 455
 456         for (i = 0; i < td->files_index; i++) {
 457                 f = td->files[i];
 458                 trace_add_open_close_event(td, f->fileno, FIO_LOG_CLOSE_FILE);
 459         }
 460
 461         fifo_free(fifo);
 462         close(fd);
 463
 464         td_restore_runstate(td, old_state);
 465
 466         if (!td->files_index) {
 467                 log_err("fio: did not find replay device(s)\n");
 468                 return 1;
 469         }
 470
 471         /*
 472          * For stacked devices, we don't always get a COMPLETE event so
 473          * the depth grows to insane values. Limit it to something sane(r).
 474          */
 475         max_depth = 0;
 476         for (i = 0; i < DDIR_RWDIR_CNT; i++) {
 477                 if (depth[i] > 1024)
 478                         depth[i] = 1024;
 479                 else if (!depth[i] && ios[i])
 480                         depth[i] = 1;
 481                 max_depth = max(depth[i], max_depth);
 482         }
 483
 484         if (skipped_writes)
 485                 log_err("fio: %s skips replay of %lu writes due to read-only\n",
 486                                                 td->o.name, skipped_writes);
 487
 488         if (!ios[DDIR_READ] && !ios[DDIR_WRITE]) {
 489                 log_err("fio: found no ios in blktrace data\n");
 490                 return 1;
 491         } else if (ios[DDIR_READ] && !ios[DDIR_WRITE]) {
 492                 td->o.td_ddir = TD_DDIR_READ;
 493                 td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 494         } else if (!ios[DDIR_READ] && ios[DDIR_WRITE]) {
 495                 td->o.td_ddir = TD_DDIR_WRITE;
 496                 td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 497         } else {
 498                 td->o.td_ddir = TD_DDIR_RW;
 499                 td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 500                 td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 501                 td->o.max_bs[DDIR_TRIM] = rw_bs[DDIR_TRIM];
 502         }
 503
 504         /*
 505          * We need to do direct/raw ios to the device, to avoid getting
 506          * read-ahead in our way.
 507          */
 508         if (!fio_option_is_set(&td->o, odirect))
 509                 td->o.odirect = 1;
 510
 511         /*
 512          * If depth wasn't manually set, use probed depth
 513          */
 514         if (!fio_option_is_set(&td->o, iodepth))
 515                 td->o.iodepth = td->o.iodepth_low = max_depth;
 516
 517         return 0;
 518 err:
 519         close(fd);
 520         fifo_free(fifo);
 521         return 1;
 522 }