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