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