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)
  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                 return 1;
  96
  97         return 0;
  98 }
  99
 100 static int lookup_device(struct thread_data *td, char *path, unsigned int maj,
 101                          unsigned int min)
 102 {
 103         struct dirent *dir;
 104         struct stat st;
 105         int found = 0;
 106         DIR *D;
 107
 108         D = opendir(path);
 109         if (!D)
 110                 return 0;
 111
 112         while ((dir = readdir(D)) != NULL) {
 113                 char full_path[256];
 114
 115                 if (!strcmp(dir->d_name, ".") || !strcmp(dir->d_name, ".."))
 116                         continue;
 117
 118                 sprintf(full_path, "%s%s%s", path, FIO_OS_PATH_SEPARATOR, dir->d_name);
 119                 if (lstat(full_path, &st) == -1) {
 120                         perror("lstat");
 121                         break;
 122                 }
 123
 124                 if (S_ISDIR(st.st_mode)) {
 125                         found = lookup_device(td, full_path, maj, min);
 126                         if (found) {
 127                                 strcpy(path, full_path);
 128                                 break;
 129                         }
 130                 }
 131
 132                 if (!S_ISBLK(st.st_mode))
 133                         continue;
 134
 135                 /*
 136                  * If replay_redirect is set then always return this device
 137                  * upon lookup which overrides the device lookup based on
 138                  * major minor in the actual blktrace
 139                  */
 140                 if (td->o.replay_redirect) {
 141                         dprint(FD_BLKTRACE, "device lookup: %d/%d\n overridden"
 142                                         " with: %s", maj, min,
 143                                         td->o.replay_redirect);
 144                         strcpy(path, td->o.replay_redirect);
 145                         found = 1;
 146                         break;
 147                 }
 148
 149                 if (maj == major(st.st_rdev) && min == minor(st.st_rdev)) {
 150                         dprint(FD_BLKTRACE, "device lookup: %d/%d\n", maj, min);
 151                         strcpy(path, full_path);
 152                         found = 1;
 153                         break;
 154                 }
 155         }
 156
 157         closedir(D);
 158         return found;
 159 }
 160
 161 #define FMINORBITS      20
 162 #define FMINORMASK      ((1U << FMINORBITS) - 1)
 163 #define FMAJOR(dev)     ((unsigned int) ((dev) >> FMINORBITS))
 164 #define FMINOR(dev)     ((unsigned int) ((dev) & FMINORMASK))
 165
 166 static void trace_add_open_event(struct thread_data *td, int fileno)
 167 {
 168         struct io_piece *ipo;
 169
 170         ipo = calloc(1, sizeof(*ipo));
 171         init_ipo(ipo);
 172
 173         ipo->ddir = DDIR_INVAL;
 174         ipo->fileno = fileno;
 175         ipo->file_action = FIO_LOG_OPEN_FILE;
 176         flist_add_tail(&ipo->list, &td->io_log_list);
 177 }
 178
 179 static void trace_add_file(struct thread_data *td, __u32 device)
 180 {
 181         static unsigned int last_maj, last_min;
 182         unsigned int maj = FMAJOR(device);
 183         unsigned int min = FMINOR(device);
 184         struct fio_file *f;
 185         char dev[256];
 186         unsigned int i;
 187
 188         if (last_maj == maj && last_min == min)
 189                 return;
 190
 191         last_maj = maj;
 192         last_min = min;
 193
 194         /*
 195          * check for this file in our list
 196          */
 197         for_each_file(td, f, i)
 198                 if (f->major == maj && f->minor == min)
 199                         return;
 200
 201         strcpy(dev, "/dev");
 202         if (lookup_device(td, dev, maj, min)) {
 203                 int fileno;
 204
 205                 dprint(FD_BLKTRACE, "add devices %s\n", dev);
 206                 fileno = add_file_exclusive(td, dev);
 207                 trace_add_open_event(td, fileno);
 208         }
 209 }
 210
 211 /*
 212  * Store blk_io_trace data in an ipo for later retrieval.
 213  */
 214 static void store_ipo(struct thread_data *td, unsigned long long offset,
 215                       unsigned int bytes, int rw, unsigned long long ttime)
 216 {
 217         struct io_piece *ipo = malloc(sizeof(*ipo));
 218
 219         init_ipo(ipo);
 220
 221         /*
 222          * the 512 is wrong here, it should be the hardware sector size...
 223          */
 224         ipo->offset = offset * 512;
 225         ipo->len = bytes;
 226         ipo->delay = ttime / 1000;
 227         if (rw)
 228                 ipo->ddir = DDIR_WRITE;
 229         else
 230                 ipo->ddir = DDIR_READ;
 231
 232         dprint(FD_BLKTRACE, "store ddir=%d, off=%llu, len=%lu, delay=%lu\n",
 233                                                         ipo->ddir, ipo->offset,
 234                                                         ipo->len, ipo->delay);
 235         queue_io_piece(td, ipo);
 236 }
 237
 238 static void handle_trace_notify(struct blk_io_trace *t)
 239 {
 240         switch (t->action) {
 241         case BLK_TN_PROCESS:
 242                 printf("got process notify: %x, %d\n", t->action, t->pid);
 243                 break;
 244         case BLK_TN_TIMESTAMP:
 245                 printf("got timestamp notify: %x, %d\n", t->action, t->pid);
 246                 break;
 247         case BLK_TN_MESSAGE:
 248                 break;
 249         default:
 250                 dprint(FD_BLKTRACE, "unknown trace act %x\n", t->action);
 251                 break;
 252         }
 253 }
 254
 255 static void handle_trace_discard(struct thread_data *td, struct blk_io_trace *t,
 256                                  unsigned long long ttime, unsigned long *ios)
 257 {
 258         struct io_piece *ipo = malloc(sizeof(*ipo));
 259
 260         init_ipo(ipo);
 261         trace_add_file(td, t->device);
 262
 263         ios[DDIR_WRITE]++;
 264         td->o.size += t->bytes;
 265
 266         memset(ipo, 0, sizeof(*ipo));
 267         INIT_FLIST_HEAD(&ipo->list);
 268
 269         /*
 270          * the 512 is wrong here, it should be the hardware sector size...
 271          */
 272         ipo->offset = t->sector * 512;
 273         ipo->len = t->bytes;
 274         ipo->delay = ttime / 1000;
 275         ipo->ddir = DDIR_TRIM;
 276
 277         dprint(FD_BLKTRACE, "store discard, off=%llu, len=%lu, delay=%lu\n",
 278                                                         ipo->offset, ipo->len,
 279                                                         ipo->delay);
 280         queue_io_piece(td, ipo);
 281 }
 282
 283 static void handle_trace_fs(struct thread_data *td, struct blk_io_trace *t,
 284                             unsigned long long ttime, unsigned long *ios,
 285                             unsigned int *bs)
 286 {
 287         int rw;
 288
 289         trace_add_file(td, t->device);
 290
 291         rw = (t->action & BLK_TC_ACT(BLK_TC_WRITE)) != 0;
 292
 293         if (t->bytes > bs[rw])
 294                 bs[rw] = t->bytes;
 295
 296         ios[rw]++;
 297         td->o.size += t->bytes;
 298         store_ipo(td, t->sector, t->bytes, rw, ttime);
 299 }
 300
 301 /*
 302  * We only care for queue traces, most of the others are side effects
 303  * due to internal workings of the block layer.
 304  */
 305 static void handle_trace(struct thread_data *td, struct blk_io_trace *t,
 306                          unsigned long long ttime, unsigned long *ios,
 307                          unsigned int *bs)
 308 {
 309         if ((t->action & 0xffff) != __BLK_TA_QUEUE)
 310                 return;
 311         if (t->action & BLK_TC_ACT(BLK_TC_PC))
 312                 return;
 313
 314         if (t->action & BLK_TC_ACT(BLK_TC_NOTIFY))
 315                 handle_trace_notify(t);
 316         else if (t->action & BLK_TC_ACT(BLK_TC_DISCARD))
 317                 handle_trace_discard(td, t, ttime, ios);
 318         else
 319                 handle_trace_fs(td, t, ttime, ios, bs);
 320 }
 321
 322 /*
 323  * Load a blktrace file by reading all the blk_io_trace entries, and storing
 324  * them as io_pieces like the fio text version would do.
 325  */
 326 int load_blktrace(struct thread_data *td, const char *filename)
 327 {
 328         unsigned long long ttime, delay;
 329         struct blk_io_trace t;
 330         unsigned long ios[2], skipped_writes;
 331         unsigned int cpu;
 332         unsigned int rw_bs[2];
 333         struct fifo *fifo;
 334         int fd;
 335
 336         fd = open(filename, O_RDONLY);
 337         if (fd < 0) {
 338                 td_verror(td, errno, "open blktrace file");
 339                 return 1;
 340         }
 341
 342         fifo = fifo_alloc(TRACE_FIFO_SIZE);
 343
 344         td->o.size = 0;
 345
 346         cpu = 0;
 347         ttime = 0;
 348         ios[0] = ios[1] = 0;
 349         rw_bs[0] = rw_bs[1] = 0;
 350         skipped_writes = 0;
 351         do {
 352                 int ret = trace_fifo_get(td, fifo, fd, &t, sizeof(t));
 353
 354                 if (ret < 0)
 355                         goto err;
 356                 else if (!ret)
 357                         break;
 358                 else if (ret < (int) sizeof(t)) {
 359                         log_err("fio: short fifo get\n");
 360                         break;
 361                 }
 362
 363                 if ((t.magic & 0xffffff00) != BLK_IO_TRACE_MAGIC) {
 364                         log_err("fio: bad magic in blktrace data: %x\n",
 365                                                                 t.magic);
 366                         goto err;
 367                 }
 368                 if ((t.magic & 0xff) != BLK_IO_TRACE_VERSION) {
 369                         log_err("fio: bad blktrace version %d\n",
 370                                                                 t.magic & 0xff);
 371                         goto err;
 372                 }
 373                 ret = discard_pdu(td, fifo, fd, &t);
 374                 if (ret < 0) {
 375                         td_verror(td, ret, "blktrace lseek");
 376                         goto err;
 377                 } else if (t.pdu_len != ret) {
 378                         log_err("fio: discarded %d of %d\n", ret, t.pdu_len);
 379                         goto err;
 380                 }
 381                 if ((t.action & BLK_TC_ACT(BLK_TC_NOTIFY)) == 0) {
 382                         if (!ttime) {
 383                                 ttime = t.time;
 384                                 cpu = t.cpu;
 385                         }
 386
 387                         delay = 0;
 388                         if (cpu == t.cpu)
 389                                 delay = t.time - ttime;
 390                         if ((t.action & BLK_TC_ACT(BLK_TC_WRITE)) && read_only)
 391                                 skipped_writes++;
 392                         else {
 393                                 /*
 394                                  * set delay to zero if no_stall enabled for
 395                                  * fast replay
 396                                  */
 397                                 if (td->o.no_stall)
 398                                         delay = 0;
 399
 400                                 handle_trace(td, &t, delay, ios, rw_bs);
 401                         }
 402
 403                         ttime = t.time;
 404                         cpu = t.cpu;
 405                 } else {
 406                         delay = 0;
 407                         handle_trace(td, &t, delay, ios, rw_bs);
 408                 }
 409         } while (1);
 410
 411         fifo_free(fifo);
 412         close(fd);
 413
 414         if (skipped_writes)
 415                 log_err("fio: %s skips replay of %lu writes due to read-only\n",
 416                                                 td->o.name, skipped_writes);
 417
 418         if (!ios[DDIR_READ] && !ios[DDIR_WRITE]) {
 419                 log_err("fio: found no ios in blktrace data\n");
 420                 return 1;
 421         } else if (ios[DDIR_READ] && !ios[DDIR_READ]) {
 422                 td->o.td_ddir = TD_DDIR_READ;
 423                 td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 424         } else if (!ios[DDIR_READ] && ios[DDIR_WRITE]) {
 425                 td->o.td_ddir = TD_DDIR_WRITE;
 426                 td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 427         } else {
 428                 td->o.td_ddir = TD_DDIR_RW;
 429                 td->o.max_bs[DDIR_READ] = rw_bs[DDIR_READ];
 430                 td->o.max_bs[DDIR_WRITE] = rw_bs[DDIR_WRITE];
 431         }
 432
 433         /*
 434          * We need to do direct/raw ios to the device, to avoid getting
 435          * read-ahead in our way.
 436          */
 437         td->o.odirect = 1;
 438
 439         return 0;
 440 err:
 441         close(fd);
 442         fifo_free(fifo);
 443         return 1;
 444 }