Documentation/perf_counter/builtin-record.c

   1 /*
   2  * builtin-record.c
   3  *
   4  * Builtin record command: Record the profile of a workload
   5  * (or a CPU, or a PID) into the perf.data output file - for
   6  * later analysis via perf report.
   7  */
   8 #include "builtin.h"
   9
  10 #include "perf.h"
  11
  12 #include "util/util.h"
  13 #include "util/parse-options.h"
  14 #include "util/parse-events.h"
  15 #include "util/string.h"
  16
  17 #include <unistd.h>
  18 #include <sched.h>
  19
  20 #define ALIGN(x, a)             __ALIGN_MASK(x, (typeof(x))(a)-1)
  21 #define __ALIGN_MASK(x, mask)   (((x)+(mask))&~(mask))
  22
  23 static long                     default_interval = 100000;
  24 static long                     event_count[MAX_COUNTERS];
  25
  26 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
  27 static int                      nr_cpus                         = 0;
  28 static unsigned int             page_size;
  29 static unsigned int             mmap_pages                      = 128;
  30 static int                      freq                            = 0;
  31 static int                      output;
  32 static const char               *output_name                    = "perf.data";
  33 static int                      group                           = 0;
  34 static unsigned int             realtime_prio                   = 0;
  35 static int                      system_wide                     = 0;
  36 static pid_t                    target_pid                      = -1;
  37 static int                      inherit                         = 1;
  38 static int                      force                           = 0;
  39 static int                      append_file                     = 0;
  40
  41 const unsigned int default_count[] = {
  42         1000000,
  43         1000000,
  44           10000,
  45           10000,
  46         1000000,
  47           10000,
  48 };
  49
  50 struct mmap_data {
  51         int counter;
  52         void *base;
  53         unsigned int mask;
  54         unsigned int prev;
  55 };
  56
  57 static unsigned int mmap_read_head(struct mmap_data *md)
  58 {
  59         struct perf_counter_mmap_page *pc = md->base;
  60         int head;
  61
  62         head = pc->data_head;
  63         rmb();
  64
  65         return head;
  66 }
  67
  68 static long samples;
  69 static struct timeval last_read, this_read;
  70
  71 static __u64 bytes_written;
  72
  73 static void mmap_read(struct mmap_data *md)
  74 {
  75         unsigned int head = mmap_read_head(md);
  76         unsigned int old = md->prev;
  77         unsigned char *data = md->base + page_size;
  78         unsigned long size;
  79         void *buf;
  80         int diff;
  81
  82         gettimeofday(&this_read, NULL);
  83
  84         /*
  85          * If we're further behind than half the buffer, there's a chance
  86          * the writer will bite our tail and mess up the samples under us.
  87          *
  88          * If we somehow ended up ahead of the head, we got messed up.
  89          *
  90          * In either case, truncate and restart at head.
  91          */
  92         diff = head - old;
  93         if (diff > md->mask / 2 || diff < 0) {
  94                 struct timeval iv;
  95                 unsigned long msecs;
  96
  97                 timersub(&this_read, &last_read, &iv);
  98                 msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
  99
 100                 fprintf(stderr, "WARNING: failed to keep up with mmap data."
 101                                 "  Last read %lu msecs ago.\n", msecs);
 102
 103                 /*
 104                  * head points to a known good entry, start there.
 105                  */
 106                 old = head;
 107         }
 108
 109         last_read = this_read;
 110
 111         if (old != head)
 112                 samples++;
 113
 114         size = head - old;
 115
 116         if ((old & md->mask) + size != (head & md->mask)) {
 117                 buf = &data[old & md->mask];
 118                 size = md->mask + 1 - (old & md->mask);
 119                 old += size;
 120
 121                 while (size) {
 122                         int ret = write(output, buf, size);
 123
 124                         if (ret < 0)
 125                                 die("failed to write");
 126
 127                         size -= ret;
 128                         buf += ret;
 129
 130                         bytes_written += ret;
 131                 }
 132         }
 133
 134         buf = &data[old & md->mask];
 135         size = head - old;
 136         old += size;
 137
 138         while (size) {
 139                 int ret = write(output, buf, size);
 140
 141                 if (ret < 0)
 142                         die("failed to write");
 143
 144                 size -= ret;
 145                 buf += ret;
 146
 147                 bytes_written += ret;
 148         }
 149
 150         md->prev = old;
 151 }
 152
 153 static volatile int done = 0;
 154
 155 static void sig_handler(int sig)
 156 {
 157         done = 1;
 158 }
 159
 160 static struct pollfd event_array[MAX_NR_CPUS * MAX_COUNTERS];
 161 static struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
 162
 163 static int nr_poll;
 164 static int nr_cpu;
 165
 166 struct mmap_event {
 167         struct perf_event_header        header;
 168         __u32                           pid;
 169         __u32                           tid;
 170         __u64                           start;
 171         __u64                           len;
 172         __u64                           pgoff;
 173         char                            filename[PATH_MAX];
 174 };
 175
 176 struct comm_event {
 177         struct perf_event_header        header;
 178         __u32                           pid;
 179         __u32                           tid;
 180         char                            comm[16];
 181 };
 182
 183 static void pid_synthesize_comm_event(pid_t pid, int full)
 184 {
 185         struct comm_event comm_ev;
 186         char filename[PATH_MAX];
 187         char bf[BUFSIZ];
 188         int fd, ret;
 189         size_t size;
 190         char *field, *sep;
 191         DIR *tasks;
 192         struct dirent dirent, *next;
 193
 194         snprintf(filename, sizeof(filename), "/proc/%d/stat", pid);
 195
 196         fd = open(filename, O_RDONLY);
 197         if (fd < 0) {
 198                 fprintf(stderr, "couldn't open %s\n", filename);
 199                 exit(EXIT_FAILURE);
 200         }
 201         if (read(fd, bf, sizeof(bf)) < 0) {
 202                 fprintf(stderr, "couldn't read %s\n", filename);
 203                 exit(EXIT_FAILURE);
 204         }
 205         close(fd);
 206
 207         /* 9027 (cat) R 6747 9027 6747 34816 9027 ... */
 208         memset(&comm_ev, 0, sizeof(comm_ev));
 209         field = strchr(bf, '(');
 210         if (field == NULL)
 211                 goto out_failure;
 212         sep = strchr(++field, ')');
 213         if (sep == NULL)
 214                 goto out_failure;
 215         size = sep - field;
 216         memcpy(comm_ev.comm, field, size++);
 217
 218         comm_ev.pid = pid;
 219         comm_ev.header.type = PERF_EVENT_COMM;
 220         size = ALIGN(size, sizeof(uint64_t));
 221         comm_ev.header.size = sizeof(comm_ev) - (sizeof(comm_ev.comm) - size);
 222
 223         if (!full) {
 224                 comm_ev.tid = pid;
 225
 226                 ret = write(output, &comm_ev, comm_ev.header.size);
 227                 if (ret < 0) {
 228                         perror("failed to write");
 229                         exit(-1);
 230                 }
 231                 return;
 232         }
 233
 234         snprintf(filename, sizeof(filename), "/proc/%d/task", pid);
 235
 236         tasks = opendir(filename);
 237         while (!readdir_r(tasks, &dirent, &next) && next) {
 238                 char *end;
 239                 pid = strtol(dirent.d_name, &end, 10);
 240                 if (*end)
 241                         continue;
 242
 243                 comm_ev.tid = pid;
 244
 245                 ret = write(output, &comm_ev, comm_ev.header.size);
 246                 if (ret < 0) {
 247                         perror("failed to write");
 248                         exit(-1);
 249                 }
 250         }
 251         closedir(tasks);
 252         return;
 253
 254 out_failure:
 255         fprintf(stderr, "couldn't get COMM and pgid, malformed %s\n",
 256                 filename);
 257         exit(EXIT_FAILURE);
 258 }
 259
 260 static void pid_synthesize_mmap_samples(pid_t pid)
 261 {
 262         char filename[PATH_MAX];
 263         FILE *fp;
 264
 265         snprintf(filename, sizeof(filename), "/proc/%d/maps", pid);
 266
 267         fp = fopen(filename, "r");
 268         if (fp == NULL) {
 269                 fprintf(stderr, "couldn't open %s\n", filename);
 270                 exit(EXIT_FAILURE);
 271         }
 272         while (1) {
 273                 char bf[BUFSIZ], *pbf = bf;
 274                 struct mmap_event mmap_ev = {
 275                         .header.type = PERF_EVENT_MMAP,
 276                 };
 277                 int n;
 278                 size_t size;
 279                 if (fgets(bf, sizeof(bf), fp) == NULL)
 280                         break;
 281
 282                 /* 00400000-0040c000 r-xp 00000000 fd:01 41038  /bin/cat */
 283                 n = hex2u64(pbf, &mmap_ev.start);
 284                 if (n < 0)
 285                         continue;
 286                 pbf += n + 1;
 287                 n = hex2u64(pbf, &mmap_ev.len);
 288                 if (n < 0)
 289                         continue;
 290                 pbf += n + 3;
 291                 if (*pbf == 'x') { /* vm_exec */
 292                         char *execname = strrchr(bf, ' ');
 293
 294                         if (execname == NULL || execname[1] != '/')
 295                                 continue;
 296
 297                         execname += 1;
 298                         size = strlen(execname);
 299                         execname[size - 1] = '\0'; /* Remove \n */
 300                         memcpy(mmap_ev.filename, execname, size);
 301                         size = ALIGN(size, sizeof(uint64_t));
 302                         mmap_ev.len -= mmap_ev.start;
 303                         mmap_ev.header.size = (sizeof(mmap_ev) -
 304                                                (sizeof(mmap_ev.filename) - size));
 305                         mmap_ev.pid = pid;
 306                         mmap_ev.tid = pid;
 307
 308                         if (write(output, &mmap_ev, mmap_ev.header.size) < 0) {
 309                                 perror("failed to write");
 310                                 exit(-1);
 311                         }
 312                 }
 313         }
 314
 315         fclose(fp);
 316 }
 317
 318 static void synthesize_samples(void)
 319 {
 320         DIR *proc;
 321         struct dirent dirent, *next;
 322
 323         proc = opendir("/proc");
 324
 325         while (!readdir_r(proc, &dirent, &next) && next) {
 326                 char *end;
 327                 pid_t pid;
 328
 329                 pid = strtol(dirent.d_name, &end, 10);
 330                 if (*end) /* only interested in proper numerical dirents */
 331                         continue;
 332
 333                 pid_synthesize_comm_event(pid, 1);
 334                 pid_synthesize_mmap_samples(pid);
 335         }
 336
 337         closedir(proc);
 338 }
 339
 340 static int group_fd;
 341
 342 static void create_counter(int counter, int cpu, pid_t pid)
 343 {
 344         struct perf_counter_attr attr;
 345         int track = 1;
 346
 347         memset(&attr, 0, sizeof(attr));
 348         attr.config             = event_id[counter];
 349         attr.sample_period      = event_count[counter];
 350         attr.sample_type        = PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_PERIOD;
 351         if (freq) {
 352                 attr.freq               = 1;
 353                 attr.sample_freq        = freq;
 354         }
 355         attr.mmap               = track;
 356         attr.comm               = track;
 357         attr.inherit            = (cpu < 0) && inherit;
 358
 359         track = 0; /* only the first counter needs these */
 360
 361         fd[nr_cpu][counter] = sys_perf_counter_open(&attr, pid, cpu, group_fd, 0);
 362
 363         if (fd[nr_cpu][counter] < 0) {
 364                 int err = errno;
 365
 366                 error("syscall returned with %d (%s)\n",
 367                                 fd[nr_cpu][counter], strerror(err));
 368                 if (err == EPERM)
 369                         printf("Are you root?\n");
 370                 exit(-1);
 371         }
 372         assert(fd[nr_cpu][counter] >= 0);
 373         fcntl(fd[nr_cpu][counter], F_SETFL, O_NONBLOCK);
 374
 375         /*
 376          * First counter acts as the group leader:
 377          */
 378         if (group && group_fd == -1)
 379                 group_fd = fd[nr_cpu][counter];
 380
 381         event_array[nr_poll].fd = fd[nr_cpu][counter];
 382         event_array[nr_poll].events = POLLIN;
 383         nr_poll++;
 384
 385         mmap_array[nr_cpu][counter].counter = counter;
 386         mmap_array[nr_cpu][counter].prev = 0;
 387         mmap_array[nr_cpu][counter].mask = mmap_pages*page_size - 1;
 388         mmap_array[nr_cpu][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
 389                         PROT_READ, MAP_SHARED, fd[nr_cpu][counter], 0);
 390         if (mmap_array[nr_cpu][counter].base == MAP_FAILED) {
 391                 error("failed to mmap with %d (%s)\n", errno, strerror(errno));
 392                 exit(-1);
 393         }
 394 }
 395
 396 static void open_counters(int cpu, pid_t pid)
 397 {
 398         int counter;
 399
 400         if (pid > 0) {
 401                 pid_synthesize_comm_event(pid, 0);
 402                 pid_synthesize_mmap_samples(pid);
 403         }
 404
 405         group_fd = -1;
 406         for (counter = 0; counter < nr_counters; counter++)
 407                 create_counter(counter, cpu, pid);
 408
 409         nr_cpu++;
 410 }
 411
 412 static int __cmd_record(int argc, const char **argv)
 413 {
 414         int i, counter;
 415         struct stat st;
 416         pid_t pid;
 417         int flags;
 418         int ret;
 419
 420         page_size = sysconf(_SC_PAGE_SIZE);
 421         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 422         assert(nr_cpus <= MAX_NR_CPUS);
 423         assert(nr_cpus >= 0);
 424
 425         if (!stat(output_name, &st) && !force && !append_file) {
 426                 fprintf(stderr, "Error, output file %s exists, use -A to append or -f to overwrite.\n",
 427                                 output_name);
 428                 exit(-1);
 429         }
 430
 431         flags = O_CREAT|O_RDWR;
 432         if (append_file)
 433                 flags |= O_APPEND;
 434         else
 435                 flags |= O_TRUNC;
 436
 437         output = open(output_name, flags, S_IRUSR|S_IWUSR);
 438         if (output < 0) {
 439                 perror("failed to create output file");
 440                 exit(-1);
 441         }
 442
 443         if (!system_wide) {
 444                 open_counters(-1, target_pid != -1 ? target_pid : getpid());
 445         } else for (i = 0; i < nr_cpus; i++)
 446                 open_counters(i, target_pid);
 447
 448         signal(SIGCHLD, sig_handler);
 449         signal(SIGINT, sig_handler);
 450
 451         if (target_pid == -1 && argc) {
 452                 pid = fork();
 453                 if (pid < 0)
 454                         perror("failed to fork");
 455
 456                 if (!pid) {
 457                         if (execvp(argv[0], (char **)argv)) {
 458                                 perror(argv[0]);
 459                                 exit(-1);
 460                         }
 461                 }
 462         }
 463
 464         if (realtime_prio) {
 465                 struct sched_param param;
 466
 467                 param.sched_priority = realtime_prio;
 468                 if (sched_setscheduler(0, SCHED_FIFO, &param)) {
 469                         printf("Could not set realtime priority.\n");
 470                         exit(-1);
 471                 }
 472         }
 473
 474         if (system_wide)
 475                 synthesize_samples();
 476
 477         while (!done) {
 478                 int hits = samples;
 479
 480                 for (i = 0; i < nr_cpu; i++) {
 481                         for (counter = 0; counter < nr_counters; counter++)
 482                                 mmap_read(&mmap_array[i][counter]);
 483                 }
 484
 485                 if (hits == samples)
 486                         ret = poll(event_array, nr_poll, 100);
 487         }
 488
 489         /*
 490          * Approximate RIP event size: 24 bytes.
 491          */
 492         fprintf(stderr,
 493                 "[ perf record: Captured and wrote %.3f MB %s (~%lld samples) ]\n",
 494                 (double)bytes_written / 1024.0 / 1024.0,
 495                 output_name,
 496                 bytes_written / 24);
 497
 498         return 0;
 499 }
 500
 501 static const char * const record_usage[] = {
 502         "perf record [<options>] [<command>]",
 503         "perf record [<options>] -- <command> [<options>]",
 504         NULL
 505 };
 506
 507 static char events_help_msg[EVENTS_HELP_MAX];
 508
 509 static const struct option options[] = {
 510         OPT_CALLBACK('e', "event", NULL, "event",
 511                      events_help_msg, parse_events),
 512         OPT_INTEGER('p', "pid", &target_pid,
 513                     "record events on existing pid"),
 514         OPT_INTEGER('r', "realtime", &realtime_prio,
 515                     "collect data with this RT SCHED_FIFO priority"),
 516         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 517                             "system-wide collection from all CPUs"),
 518         OPT_BOOLEAN('A', "append", &append_file,
 519                             "append to the output file to do incremental profiling"),
 520         OPT_BOOLEAN('f', "force", &force,
 521                         "overwrite existing data file"),
 522         OPT_LONG('c', "count", &default_interval,
 523                     "event period to sample"),
 524         OPT_STRING('o', "output", &output_name, "file",
 525                     "output file name"),
 526         OPT_BOOLEAN('i', "inherit", &inherit,
 527                     "child tasks inherit counters"),
 528         OPT_INTEGER('F', "freq", &freq,
 529                     "profile at this frequency"),
 530         OPT_INTEGER('m', "mmap-pages", &mmap_pages,
 531                     "number of mmap data pages"),
 532         OPT_END()
 533 };
 534
 535 int cmd_record(int argc, const char **argv, const char *prefix)
 536 {
 537         int counter;
 538
 539         create_events_help(events_help_msg);
 540
 541         argc = parse_options(argc, argv, options, record_usage, 0);
 542         if (!argc && target_pid == -1 && !system_wide)
 543                 usage_with_options(record_usage, options);
 544
 545         if (!nr_counters) {
 546                 nr_counters = 1;
 547                 event_id[0] = 0;
 548         }
 549
 550         for (counter = 0; counter < nr_counters; counter++) {
 551                 if (event_count[counter])
 552                         continue;
 553
 554                 event_count[counter] = default_interval;
 555         }
 556
 557         return __cmd_record(argc, argv);
 558 }