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                 trace_add_open_close_event(td, fileno, FIO_LOG_OPEN_FILE);
 221                 last_fileno = fileno;
 222         }
 223         return last_fileno;
 224 }
 225
 226 /*
 227  * Store blk_io_trace data in an ipo for later retrieval.
 228  */
 229 static void store_ipo(struct thread_data *td, unsigned long long offset,
 230                       unsigned int bytes, int rw, unsigned long long ttime,
 231                       int fileno)
 232 {
 233         struct io_piece *ipo = malloc(sizeof(*ipo));
 234
 235         init_ipo(ipo);
 236
 237         /*
 238          * the 512 is wrong here, it should be the hardware sector size...
 239          */
 240         ipo->offset = offset * 512;
 241         ipo->len = bytes;
 242         ipo->delay = ttime / 1000;
 243         if (rw)
 244                 ipo->ddir = DDIR_WRITE;
 245         else
 246                 ipo->ddir = DDIR_READ;
 247         ipo->fileno = fileno;
 248
 249         dprint(FD_BLKTRACE, "store ddir=%d, off=%llu, len=%lu, delay=%lu\n",
 250                                                         ipo->ddir, ipo->offset,
 251                                                         ipo->len, ipo->delay);
 252         queue_io_piece(td, ipo);
 253 }
 254
 255 static void handle_trace_notify(struct blk_io_trace *t)
 256 {
 257         switch (t->action) {
 258         case BLK_TN_PROCESS:
 259                 log_info("blktrace: got process notify: %x, %d\n",
 260                                 t->action, t->pid);
 261                 break;
 262         case BLK_TN_TIMESTAMP:
 263                 log_info("blktrace: got timestamp notify: %x, %d\n",
 264                                 t->action, t->pid);
 265                 break;
 266         case BLK_TN_MESSAGE:
 267                 break;
 268         default:
 269                 dprint(FD_BLKTRACE, "unknown trace act %x\n", t->action);
 270                 break;
 271         }
 272 }
 273
 274 static void handle_trace_discard(struct thread_data *td, struct blk_io_trace *t,
 275                                  unsigned long long ttime, unsigned long *ios)
 276 {
 277         struct io_piece *ipo = malloc(sizeof(*ipo));
 278         int fileno;
 279
 280         init_ipo(ipo);
 281         fileno = trace_add_file(td, t->device);
 282
 283         ios[DDIR_WRITE]++;
 284         td->o.size += t->bytes;
 285
 286         memset(ipo, 0, sizeof(*ipo));
 287         INIT_FLIST_HEAD(&ipo->list);
 288
 289         /*
 290          * the 512 is wrong here, it should be the hardware sector size...
 291          */
 292         ipo->offset = t->sector * 512;
 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 *bs)
 307 {
 308         int rw;
 309         int fileno;
 310
 311         fileno = trace_add_file(td, t->device);
 312
 313         rw = (t->action & BLK_TC_ACT(BLK_TC_WRITE)) != 0;
 314
 315         if (t->bytes > bs[rw])
 316                 bs[rw] = t->bytes;
 317
 318         ios[rw]++;
 319         td->o.size += t->bytes;
 320         store_ipo(td, t->sector, t->bytes, rw, ttime, fileno);
 321 }
 322
 323 /*
 324  * We only care for queue traces, most of the others are side effects
 325  * due to internal workings of the block layer.
 326  */
 327 static void handle_trace(struct thread_data *td, struct blk_io_trace *t,
 328                          unsigned long long ttime, unsigned long *ios,
 329                          unsigned int *bs)
 330 {
 331         if ((t->action & 0xffff) != __BLK_TA_QUEUE)
 332                 return;
 333         if (t->action & BLK_TC_ACT(BLK_TC_PC))
 334                 return;
 335
 336         if (t->action & BLK_TC_ACT(BLK_TC_NOTIFY))
 337                 handle_trace_notify(t);
 338         else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
 339                 handle_trace_discard(td, t, ttime, ios);
 340         else
 341                 handle_trace_fs(td, t, ttime, ios, bs);
 342 }
 343
 344 static void byteswap_trace(struct blk_io_trace *t)
 345 {
 346         t->magic = fio_swap32(t->magic);
 347         t->sequence = fio_swap32(t->sequence);
 348         t->time = fio_swap64(t->time);
 349         t->sector = fio_swap64(t->sector);
 350         t->bytes = fio_swap32(t->bytes);
 351         t->action = fio_swap32(t->action);
 352         t->pid = fio_swap32(t->pid);
 353         t->device = fio_swap32(t->device);
 354         t->cpu = fio_swap32(t->cpu);
 355         t->error = fio_swap16(t->error);
 356         t->pdu_len = fio_swap16(t->pdu_len);
 357 }
 358
 359 /*
 360  * Load a blktrace file by reading all the blk_io_trace entries, and storing
 361  * them as io_pieces like the fio text version would do.
 362  */
 363 int load_blktrace(struct thread_data *td, const char *filename, int need_swap)
 364 {
 365         unsigned long long ttime, delay;
 366         struct blk_io_trace t;
 367         unsigned long ios[2], skipped_writes;
 368         unsigned int cpu;
 369         unsigned int rw_bs[2];
 370         struct fifo *fifo;
 371         int fd, i;
 372         struct fio_file *f;
 373
 374         fd = open(filename, O_RDONLY);
 375         if (fd < 0) {
 376                 td_verror(td, errno, "open blktrace file");
 377                 return 1;
 378         }
 379
 380         fifo = fifo_alloc(TRACE_FIFO_SIZE);
 381
 382         td->o.size = 0;
 383
 384         cpu = 0;
 385         ttime = 0;
 386         ios[0] = ios[1] = 0;
 387         rw_bs[0] = rw_bs[1] = 0;
 388         skipped_writes = 0;
 389         do {
 390                 int ret = trace_fifo_get(td, fifo, fd, &t, sizeof(t));
 391
 392                 if (ret < 0)
 393                         goto err;
 394                 else if (!ret)
 395                         break;
 396                 else if (ret < (int) sizeof(t)) {
 397                         log_err("fio: short fifo get\n");
 398                         break;
 399                 }
 400
 401                 if (need_swap)
 402                         byteswap_trace(&t);
 403
 404                 if ((t.magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) {
 405                         log_err("fio: bad magic in blktrace data: %x\n",
 406                                                                 t.magic);
 407                         goto err;
 408                 }
 409                 if ((t.magic & 0xff) != BLK_IO_TRACE_VERSION) {
 410                         log_err("fio: bad blktrace version %d\n",
 411                                                                 t.magic & 0xff);
 412                         goto err;
 413                 }
 414                 ret = discard_pdu(td, fifo, fd, &t);
 415                 if (ret < 0) {
 416                         td_verror(td, ret, "blktrace lseek");
 417                         goto err;
 418                 } else if (t.pdu_len != ret) {
 419                         log_err("fio: discarded %d of %d\n", ret, t.pdu_len);
 420                         goto err;
 421                 }
 422                 if ((t.action & BLK_TC_ACT(BLK_TC_NOTIFY)) == 0) {
 423                         if (!ttime) {
 424                                 ttime = t.time;
 425                                 cpu = t.cpu;
 426                         }
 427
 428                         delay = 0;
 429                         if (cpu == t.cpu)
 430                                 delay = t.time - ttime;
 431                         if ((t.action & BLK_TC_ACT(BLK_TC_WRITE)) && read_only)
 432                                 skipped_writes++;
 433                         else {
 434                                 /*
 435                                  * set delay to zero if no_stall enabled for
 436                                  * fast replay
 437                                  */
 438                                 if (td->o.no_stall)
 439                                         delay = 0;
 440
 441                                 handle_trace(td, &t, delay, ios, rw_bs);
 442                         }
 443
 444                         ttime = t.time;
 445                         cpu = t.cpu;
 446                 } else {
 447                         delay = 0;
 448                         handle_trace(td, &t, delay, ios, rw_bs);
 449                 }
 450         } while (1);
 451
 452         for (i = 0; i < td->files_index; i++) {
 453                 f= td->files[i];
 454                 trace_add_open_close_event(td, f->fileno, FIO_LOG_CLOSE_FILE);
 455         }
 456
 457         fifo_free(fifo);
 458         close(fd);
 459
 460         if (skipped_writes)
 461                 log_err("fio: %s skips replay of %lu writes due to read-only\n",
 462                                                 td->o.name, skipped_writes);
 463
 464         if (!ios[DDIR_READ] && !ios[DDIR_WRITE]) {
 465                 log_err("fio: found no ios in blktrace data\n");
 466                 return 1;
 467         } else if (ios[DDIR_READ] && !ios[DDIR_READ]) {
 468                 td->o.td_ddir = TD_DDIR_READ;
 469                 td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 470         } else if (!ios[DDIR_READ] && ios[DDIR_WRITE]) {
 471                 td->o.td_ddir = TD_DDIR_WRITE;
 472                 td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 473         } else {
 474                 td->o.td_ddir = TD_DDIR_RW;
 475                 td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 476                 td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 477         }
 478
 479         /*
 480          * We need to do direct/raw ios to the device, to avoid getting
 481          * read-ahead in our way.
 482          */
 483         td->o.odirect = 1;
 484
 485         return 0;
 486 err:
 487         close(fd);
 488         fifo_free(fifo);
 489         return 1;
 490 }