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 <sys/ioctl.h>
   8 #include <linux/fs.h>
   9 #include <dirent.h>
  10
  11 #include "flist.h"
  12 #include "fio.h"
  13 #include "blktrace.h"
  14 #include "blktrace_api.h"
  15 #include "oslib/linux-dev-lookup.h"
  16
  17 #define TRACE_FIFO_SIZE 8192
  18
  19 /*
  20  * fifo refill frontend, to avoid reading data in trace sized bites
  21  */
  22 static int refill_fifo(struct thread_data *td, struct fifo *fifo, int fd)
  23 {
  24         char buf[TRACE_FIFO_SIZE];
  25         unsigned int total;
  26         int ret;
  27
  28         total = sizeof(buf);
  29         if (total > fifo_room(fifo))
  30                 total = fifo_room(fifo);
  31
  32         ret = read(fd, buf, total);
  33         if (ret < 0) {
  34                 td_verror(td, errno, "read blktrace file");
  35                 return -1;
  36         }
  37
  38         if (ret > 0)
  39                 ret = fifo_put(fifo, buf, ret);
  40
  41         dprint(FD_BLKTRACE, "refill: filled %d bytes\n", ret);
  42         return ret;
  43 }
  44
  45 /*
  46  * Retrieve 'len' bytes from the fifo, refilling if necessary.
  47  */
  48 static int trace_fifo_get(struct thread_data *td, struct fifo *fifo, int fd,
  49                           void *buf, unsigned int len)
  50 {
  51         if (fifo_len(fifo) < len) {
  52                 int ret = refill_fifo(td, fifo, fd);
  53
  54                 if (ret < 0)
  55                         return ret;
  56         }
  57
  58         return fifo_get(fifo, buf, len);
  59 }
  60
  61 /*
  62  * Just discard the pdu by seeking past it.
  63  */
  64 static int discard_pdu(struct thread_data *td, struct fifo *fifo, int fd,
  65                        struct blk_io_trace *t)
  66 {
  67         if (t->pdu_len == 0)
  68                 return 0;
  69
  70         dprint(FD_BLKTRACE, "discard pdu len %u\n", t->pdu_len);
  71         return trace_fifo_get(td, fifo, fd, NULL, t->pdu_len);
  72 }
  73
  74 /*
  75  * Check if this is a blktrace binary data file. We read a single trace
  76  * into memory and check for the magic signature.
  77  */
  78 int is_blktrace(const char *filename, int *need_swap)
  79 {
  80         struct blk_io_trace t;
  81         int fd, ret;
  82
  83         fd = open(filename, O_RDONLY);
  84         if (fd < 0)
  85                 return 0;
  86
  87         ret = read(fd, &t, sizeof(t));
  88         close(fd);
  89
  90         if (ret < 0) {
  91                 perror("read blktrace");
  92                 return 0;
  93         } else if (ret != sizeof(t)) {
  94                 log_err("fio: short read on blktrace file\n");
  95                 return 0;
  96         }
  97
  98         if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
  99                 *need_swap = 0;
 100                 return 1;
 101         }
 102
 103         /*
 104          * Maybe it needs to be endian swapped...
 105          */
 106         t.magic = fio_swap32(t.magic);
 107         if ((t.magic & 0xffffff00) == BLK_IO_TRACE_MAGIC) {
 108                 *need_swap = 1;
 109                 return 1;
 110         }
 111
 112         return 0;
 113 }
 114
 115 #define FMINORBITS      20
 116 #define FMINORMASK      ((1U << FMINORBITS) - 1)
 117 #define FMAJOR(dev)     ((unsigned int) ((dev) >> FMINORBITS))
 118 #define FMINOR(dev)     ((unsigned int) ((dev) & FMINORMASK))
 119
 120 static void trace_add_open_close_event(struct thread_data *td, int fileno, enum file_log_act action)
 121 {
 122         struct io_piece *ipo;
 123
 124         ipo = calloc(1, sizeof(*ipo));
 125         init_ipo(ipo);
 126
 127         ipo->ddir = DDIR_INVAL;
 128         ipo->fileno = fileno;
 129         ipo->file_action = action;
 130         flist_add_tail(&ipo->list, &td->io_log_list);
 131 }
 132
 133 static int get_dev_blocksize(const char *dev, unsigned int *bs)
 134 {
 135         int fd;
 136
 137         fd = open(dev, O_RDONLY);
 138         if (fd < 0)
 139                 return 1;
 140
 141         if (ioctl(fd, BLKSSZGET, bs) < 0) {
 142                 close(fd);
 143                 return 1;
 144         }
 145
 146         close(fd);
 147         return 0;
 148 }
 149
 150 static int trace_add_file(struct thread_data *td, __u32 device,
 151                           unsigned int *bs)
 152 {
 153         static unsigned int last_maj, last_min, last_fileno, last_bs;
 154         unsigned int maj = FMAJOR(device);
 155         unsigned int min = FMINOR(device);
 156         struct fio_file *f;
 157         unsigned int i;
 158         char dev[256];
 159
 160         if (last_maj == maj && last_min == min) {
 161                 *bs = last_bs;
 162                 return last_fileno;
 163         }
 164
 165         last_maj = maj;
 166         last_min = min;
 167
 168         /*
 169          * check for this file in our list
 170          */
 171         for_each_file(td, f, i) {
 172                 if (f->major == maj && f->minor == min) {
 173                         last_fileno = f->fileno;
 174                         last_bs = f->bs;
 175                         goto out;
 176                 }
 177         }
 178
 179         strcpy(dev, "/dev");
 180         if (blktrace_lookup_device(td->o.replay_redirect, dev, maj, min)) {
 181                 unsigned int this_bs;
 182                 int fileno;
 183
 184                 if (td->o.replay_redirect)
 185                         dprint(FD_BLKTRACE, "device lookup: %d/%d\n overridden"
 186                                         " with: %s\n", maj, min,
 187                                         td->o.replay_redirect);
 188                 else
 189                         dprint(FD_BLKTRACE, "device lookup: %d/%d\n", maj, min);
 190
 191                 dprint(FD_BLKTRACE, "add devices %s\n", dev);
 192                 fileno = add_file_exclusive(td, dev);
 193
 194                 if (get_dev_blocksize(dev, &this_bs))
 195                         this_bs = 512;
 196
 197                 td->o.open_files++;
 198                 td->files[fileno]->major = maj;
 199                 td->files[fileno]->minor = min;
 200                 td->files[fileno]->bs = this_bs;
 201                 trace_add_open_close_event(td, fileno, FIO_LOG_OPEN_FILE);
 202
 203                 last_fileno = fileno;
 204                 last_bs = this_bs;
 205         }
 206
 207 out:
 208         *bs = last_bs;
 209         return last_fileno;
 210 }
 211
 212 static void t_bytes_align(struct thread_options *o, struct blk_io_trace *t)
 213 {
 214         if (!o->replay_align)
 215                 return;
 216
 217         t->bytes = (t->bytes + o->replay_align - 1) & ~(o->replay_align - 1);
 218 }
 219
 220 /*
 221  * Store blk_io_trace data in an ipo for later retrieval.
 222  */
 223 static void store_ipo(struct thread_data *td, unsigned long long offset,
 224                       unsigned int bytes, int rw, unsigned long long ttime,
 225                       int fileno, unsigned int bs)
 226 {
 227         struct io_piece *ipo = malloc(sizeof(*ipo));
 228
 229         init_ipo(ipo);
 230
 231         ipo->offset = offset * bs;
 232         if (td->o.replay_scale)
 233                 ipo->offset = ipo->offset / td->o.replay_scale;
 234         ipo_bytes_align(td->o.replay_align, ipo);
 235         ipo->len = bytes;
 236         ipo->delay = ttime / 1000;
 237         if (rw)
 238                 ipo->ddir = DDIR_WRITE;
 239         else
 240                 ipo->ddir = DDIR_READ;
 241         ipo->fileno = fileno;
 242
 243         dprint(FD_BLKTRACE, "store ddir=%d, off=%llu, len=%lu, delay=%lu\n",
 244                                                         ipo->ddir, ipo->offset,
 245                                                         ipo->len, ipo->delay);
 246         queue_io_piece(td, ipo);
 247 }
 248
 249 static void handle_trace_notify(struct blk_io_trace *t)
 250 {
 251         switch (t->action) {
 252         case BLK_TN_PROCESS:
 253                 dprint(FD_BLKTRACE, "got process notify: %x, %d\n",
 254                                 t->action, t->pid);
 255                 break;
 256         case BLK_TN_TIMESTAMP:
 257                 dprint(FD_BLKTRACE, "got timestamp notify: %x, %d\n",
 258                                 t->action, t->pid);
 259                 break;
 260         case BLK_TN_MESSAGE:
 261                 break;
 262         default:
 263                 dprint(FD_BLKTRACE, "unknown trace act %x\n", t->action);
 264                 break;
 265         }
 266 }
 267
 268 static void handle_trace_discard(struct thread_data *td,
 269                                  struct blk_io_trace *t,
 270                                  unsigned long long ttime,
 271                                  unsigned long *ios, unsigned int *rw_bs)
 272 {
 273         struct io_piece *ipo = malloc(sizeof(*ipo));
 274         unsigned int bs;
 275         int fileno;
 276
 277         init_ipo(ipo);
 278         fileno = trace_add_file(td, t->device, &bs);
 279
 280         ios[DDIR_TRIM]++;
 281         if (t->bytes > rw_bs[DDIR_TRIM])
 282                 rw_bs[DDIR_TRIM] = t->bytes;
 283
 284         td->o.size += t->bytes;
 285
 286         memset(ipo, 0, sizeof(*ipo));
 287         INIT_FLIST_HEAD(&ipo->list);
 288
 289         ipo->offset = t->sector * bs;
 290         if (td->o.replay_scale)
 291                 ipo->offset = ipo->offset / td->o.replay_scale;
 292         ipo_bytes_align(td->o.replay_align, ipo);
 293         ipo->len = t->bytes;
 294         ipo->delay = ttime / 1000;
 295         ipo->ddir = DDIR_TRIM;
 296         ipo->fileno = fileno;
 297
 298         dprint(FD_BLKTRACE, "store discard, off=%llu, len=%lu, delay=%lu\n",
 299                                                         ipo->offset, ipo->len,
 300                                                         ipo->delay);
 301         queue_io_piece(td, ipo);
 302 }
 303
 304 static void handle_trace_fs(struct thread_data *td, struct blk_io_trace *t,
 305                             unsigned long long ttime, unsigned long *ios,
 306                             unsigned int *rw_bs)
 307 {
 308         unsigned int bs;
 309         int rw;
 310         int fileno;
 311
 312         fileno = trace_add_file(td, t->device, &bs);
 313
 314         rw = (t->action & BLK_TC_ACT(BLK_TC_WRITE)) != 0;
 315
 316         if (t->bytes > rw_bs[rw])
 317                 rw_bs[rw] = t->bytes;
 318
 319         ios[rw]++;
 320         td->o.size += t->bytes;
 321         store_ipo(td, t->sector, t->bytes, rw, ttime, fileno, bs);
 322 }
 323
 324 /*
 325  * We only care for queue traces, most of the others are side effects
 326  * due to internal workings of the block layer.
 327  */
 328 static void handle_trace(struct thread_data *td, struct blk_io_trace *t,
 329                          unsigned long *ios, unsigned int *bs)
 330 {
 331         static unsigned long long last_ttime;
 332         unsigned long long delay = 0;
 333
 334         if ((t->action & 0xffff) != __BLK_TA_QUEUE)
 335                 return;
 336
 337         if (!(t->action & BLK_TC_ACT(BLK_TC_NOTIFY))) {
 338                 if (!last_ttime || td->o.no_stall) {
 339                         last_ttime = t->time;
 340                         delay = 0;
 341                 } else {
 342                         delay = t->time - last_ttime;
 343                         last_ttime = t->time;
 344                 }
 345         }
 346
 347         t_bytes_align(&td->o, t);
 348
 349         if (t->action & BLK_TC_ACT(BLK_TC_NOTIFY))
 350                 handle_trace_notify(t);
 351         else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
 352                 handle_trace_discard(td, t, delay, ios, bs);
 353         else
 354                 handle_trace_fs(td, t, delay, ios, bs);
 355 }
 356
 357 static void byteswap_trace(struct blk_io_trace *t)
 358 {
 359         t->magic = fio_swap32(t->magic);
 360         t->sequence = fio_swap32(t->sequence);
 361         t->time = fio_swap64(t->time);
 362         t->sector = fio_swap64(t->sector);
 363         t->bytes = fio_swap32(t->bytes);
 364         t->action = fio_swap32(t->action);
 365         t->pid = fio_swap32(t->pid);
 366         t->device = fio_swap32(t->device);
 367         t->cpu = fio_swap32(t->cpu);
 368         t->error = fio_swap16(t->error);
 369         t->pdu_len = fio_swap16(t->pdu_len);
 370 }
 371
 372 static int t_is_write(struct blk_io_trace *t)
 373 {
 374         return (t->action & BLK_TC_ACT(BLK_TC_WRITE | BLK_TC_DISCARD)) != 0;
 375 }
 376
 377 static enum fio_ddir t_get_ddir(struct blk_io_trace *t)
 378 {
 379         if (t->action & BLK_TC_ACT(BLK_TC_READ))
 380                 return DDIR_READ;
 381         else if (t->action & BLK_TC_ACT(BLK_TC_WRITE))
 382                 return DDIR_WRITE;
 383         else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
 384                 return DDIR_TRIM;
 385
 386         return DDIR_INVAL;
 387 }
 388
 389 static void depth_inc(struct blk_io_trace *t, int *depth)
 390 {
 391         enum fio_ddir ddir;
 392
 393         ddir = t_get_ddir(t);
 394         if (ddir != DDIR_INVAL)
 395                 depth[ddir]++;
 396 }
 397
 398 static void depth_dec(struct blk_io_trace *t, int *depth)
 399 {
 400         enum fio_ddir ddir;
 401
 402         ddir = t_get_ddir(t);
 403         if (ddir != DDIR_INVAL)
 404                 depth[ddir]--;
 405 }
 406
 407 static void depth_end(struct blk_io_trace *t, int *this_depth, int *depth)
 408 {
 409         enum fio_ddir ddir = DDIR_INVAL;
 410
 411         ddir = t_get_ddir(t);
 412         if (ddir != DDIR_INVAL) {
 413                 depth[ddir] = max(depth[ddir], this_depth[ddir]);
 414                 this_depth[ddir] = 0;
 415         }
 416 }
 417
 418 /*
 419  * Load a blktrace file by reading all the blk_io_trace entries, and storing
 420  * them as io_pieces like the fio text version would do.
 421  */
 422 int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 423 {
 424         struct blk_io_trace t;
 425         unsigned long ios[DDIR_RWDIR_CNT], skipped_writes;
 426         unsigned int rw_bs[DDIR_RWDIR_CNT];
 427         struct fifo *fifo;
 428         int fd, i, old_state;
 429         struct fio_file *f;
 430         int this_depth[DDIR_RWDIR_CNT], depth[DDIR_RWDIR_CNT], max_depth;
 431
 432         fd = open(filename, O_RDONLY);
 433         if (fd < 0) {
 434                 td_verror(td, errno, "open blktrace file");
 435                 return 1;
 436         }
 437
 438         fifo = fifo_alloc(TRACE_FIFO_SIZE);
 439
 440         old_state = td_bump_runstate(td, TD_SETTING_UP);
 441
 442         td->o.size = 0;
 443
 444         for (i = 0; i < DDIR_RWDIR_CNT; i++) {
 445                 ios[i] = 0;
 446                 rw_bs[i] = 0;
 447                 this_depth[i] = 0;
 448                 depth[i] = 0;
 449         }
 450
 451         skipped_writes = 0;
 452         do {
 453                 int ret = trace_fifo_get(td, fifo, fd, &t, sizeof(t));
 454
 455                 if (ret < 0)
 456                         goto err;
 457                 else if (!ret)
 458                         break;
 459                 else if (ret < (int) sizeof(t)) {
 460                         log_err("fio: short fifo get\n");
 461                         break;
 462                 }
 463
 464                 if (need_swap)
 465                         byteswap_trace(&t);
 466
 467                 if ((t.magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) {
 468                         log_err("fio: bad magic in blktrace data: %x\n",
 469                                                                 t.magic);
 470                         goto err;
 471                 }
 472                 if ((t.magic & 0xff) != BLK_IO_TRACE_VERSION) {
 473                         log_err("fio: bad blktrace version %d\n",
 474                                                                 t.magic & 0xff);
 475                         goto err;
 476                 }
 477                 ret = discard_pdu(td, fifo, fd, &t);
 478                 if (ret < 0) {
 479                         td_verror(td, ret, "blktrace lseek");
 480                         goto err;
 481                 } else if (t.pdu_len != ret) {
 482                         log_err("fio: discarded %d of %d\n", ret, t.pdu_len);
 483                         goto err;
 484                 }
 485                 if ((t.action & BLK_TC_ACT(BLK_TC_NOTIFY)) == 0) {
 486                         if ((t.action & 0xffff) == __BLK_TA_QUEUE)
 487                                 depth_inc(&t, this_depth);
 488                         else if (((t.action & 0xffff) == __BLK_TA_BACKMERGE) ||
 489                                 ((t.action & 0xffff) == __BLK_TA_FRONTMERGE))
 490                                 depth_dec(&t, this_depth);
 491                         else if ((t.action & 0xffff) == __BLK_TA_COMPLETE)
 492                                 depth_end(&t, this_depth, depth);
 493
 494                         if (t_is_write(&t) && read_only) {
 495                                 skipped_writes++;
 496                                 continue;
 497                         }
 498                 }
 499
 500                 handle_trace(td, &t, ios, rw_bs);
 501         } while (1);
 502
 503         for (i = 0; i < td->files_index; i++) {
 504                 f = td->files[i];
 505                 trace_add_open_close_event(td, f->fileno, FIO_LOG_CLOSE_FILE);
 506         }
 507
 508         fifo_free(fifo);
 509         close(fd);
 510
 511         td_restore_runstate(td, old_state);
 512
 513         if (!td->files_index) {
 514                 log_err("fio: did not find replay device(s)\n");
 515                 return 1;
 516         }
 517
 518         /*
 519          * For stacked devices, we don't always get a COMPLETE event so
 520          * the depth grows to insane values. Limit it to something sane(r).
 521          */
 522         max_depth = 0;
 523         for (i = 0; i < DDIR_RWDIR_CNT; i++) {
 524                 if (depth[i] > 1024)
 525                         depth[i] = 1024;
 526                 else if (!depth[i] && ios[i])
 527                         depth[i] = 1;
 528                 max_depth = max(depth[i], max_depth);
 529         }
 530
 531         if (skipped_writes)
 532                 log_err("fio: %s skips replay of %lu writes due to read-only\n",
 533                                                 td->o.name, skipped_writes);
 534
 535         if (!ios[DDIR_READ] && !ios[DDIR_WRITE]) {
 536                 log_err("fio: found no ios in blktrace data\n");
 537                 return 1;
 538         } else if (ios[DDIR_READ] && !ios[DDIR_WRITE]) {
 539                 td->o.td_ddir = TD_DDIR_READ;
 540                 td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 541         } else if (!ios[DDIR_READ] && ios[DDIR_WRITE]) {
 542                 td->o.td_ddir = TD_DDIR_WRITE;
 543                 td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 544         } else {
 545                 td->o.td_ddir = TD_DDIR_RW;
 546                 td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 547                 td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 548                 td->o.max_bs[DDIR_TRIM] = rw_bs[DDIR_TRIM];
 549         }
 550
 551         /*
 552          * We need to do direct/raw ios to the device, to avoid getting
 553          * read-ahead in our way. But only do so if the minimum block size
 554          * is a multiple of 4k, otherwise we don't know if it's safe to do so.
 555          */
 556         if (!fio_option_is_set(&td->o, odirect) && !(td_min_bs(td) & 4095))
 557                 td->o.odirect = 1;
 558
 559         /*
 560          * If depth wasn't manually set, use probed depth
 561          */
 562         if (!fio_option_is_set(&td->o, iodepth))
 563                 td->o.iodepth = td->o.iodepth_low = max_depth;
 564
 565         return 0;
 566 err:
 567         close(fd);
 568         fifo_free(fifo);
 569         return 1;
 570 }