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