tools/perf/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 int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
  24
  25 static long                     default_interval                = 100000;
  26
  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 static int                      verbose                         = 0;
  41
  42 static long                     samples;
  43 static struct timeval           last_read;
  44 static struct timeval           this_read;
  45
  46 static __u64                    bytes_written;
  47
  48 static struct pollfd            event_array[MAX_NR_CPUS * MAX_COUNTERS];
  49
  50 static int                      nr_poll;
  51 static int                      nr_cpu;
  52
  53 struct mmap_event {
  54         struct perf_event_header        header;
  55         __u32                           pid;
  56         __u32                           tid;
  57         __u64                           start;
  58         __u64                           len;
  59         __u64                           pgoff;
  60         char                            filename[PATH_MAX];
  61 };
  62
  63 struct comm_event {
  64         struct perf_event_header        header;
  65         __u32                           pid;
  66         __u32                           tid;
  67         char                            comm[16];
  68 };
  69
  70
  71 struct mmap_data {
  72         int                     counter;
  73         void                    *base;
  74         unsigned int            mask;
  75         unsigned int            prev;
  76 };
  77
  78 static struct mmap_data         mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
  79
  80 static unsigned int mmap_read_head(struct mmap_data *md)
  81 {
  82         struct perf_counter_mmap_page *pc = md->base;
  83         int head;
  84
  85         head = pc->data_head;
  86         rmb();
  87
  88         return head;
  89 }
  90
  91 static void mmap_read(struct mmap_data *md)
  92 {
  93         unsigned int head = mmap_read_head(md);
  94         unsigned int old = md->prev;
  95         unsigned char *data = md->base + page_size;
  96         unsigned long size;
  97         void *buf;
  98         int diff;
  99
 100         gettimeofday(&this_read, NULL);
 101
 102         /*
 103          * If we're further behind than half the buffer, there's a chance
 104          * the writer will bite our tail and mess up the samples under us.
 105          *
 106          * If we somehow ended up ahead of the head, we got messed up.
 107          *
 108          * In either case, truncate and restart at head.
 109          */
 110         diff = head - old;
 111         if (diff > md->mask / 2 || diff < 0) {
 112                 struct timeval iv;
 113                 unsigned long msecs;
 114
 115                 timersub(&this_read, &last_read, &iv);
 116                 msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
 117
 118                 fprintf(stderr, "WARNING: failed to keep up with mmap data."
 119                                 "  Last read %lu msecs ago.\n", msecs);
 120
 121                 /*
 122                  * head points to a known good entry, start there.
 123                  */
 124                 old = head;
 125         }
 126
 127         last_read = this_read;
 128
 129         if (old != head)
 130                 samples++;
 131
 132         size = head - old;
 133
 134         if ((old & md->mask) + size != (head & md->mask)) {
 135                 buf = &data[old & md->mask];
 136                 size = md->mask + 1 - (old & md->mask);
 137                 old += size;
 138
 139                 while (size) {
 140                         int ret = write(output, buf, size);
 141
 142                         if (ret < 0)
 143                                 die("failed to write");
 144
 145                         size -= ret;
 146                         buf += ret;
 147
 148                         bytes_written += ret;
 149                 }
 150         }
 151
 152         buf = &data[old & md->mask];
 153         size = head - old;
 154         old += size;
 155
 156         while (size) {
 157                 int ret = write(output, buf, size);
 158
 159                 if (ret < 0)
 160                         die("failed to write");
 161
 162                 size -= ret;
 163                 buf += ret;
 164
 165                 bytes_written += ret;
 166         }
 167
 168         md->prev = old;
 169 }
 170
 171 static volatile int done = 0;
 172 static volatile int signr = -1;
 173
 174 static void sig_handler(int sig)
 175 {
 176         done = 1;
 177         signr = sig;
 178 }
 179
 180 static void sig_atexit(void)
 181 {
 182         if (signr == -1)
 183                 return;
 184
 185         signal(signr, SIG_DFL);
 186         kill(getpid(), signr);
 187 }
 188
 189 static void pid_synthesize_comm_event(pid_t pid, int full)
 190 {
 191         struct comm_event comm_ev;
 192         char filename[PATH_MAX];
 193         char bf[BUFSIZ];
 194         int fd, ret;
 195         size_t size;
 196         char *field, *sep;
 197         DIR *tasks;
 198         struct dirent dirent, *next;
 199
 200         snprintf(filename, sizeof(filename), "/proc/%d/stat", pid);
 201
 202         fd = open(filename, O_RDONLY);
 203         if (fd < 0) {
 204                 fprintf(stderr, "couldn't open %s\n", filename);
 205                 exit(EXIT_FAILURE);
 206         }
 207         if (read(fd, bf, sizeof(bf)) < 0) {
 208                 fprintf(stderr, "couldn't read %s\n", filename);
 209                 exit(EXIT_FAILURE);
 210         }
 211         close(fd);
 212
 213         /* 9027 (cat) R 6747 9027 6747 34816 9027 ... */
 214         memset(&comm_ev, 0, sizeof(comm_ev));
 215         field = strchr(bf, '(');
 216         if (field == NULL)
 217                 goto out_failure;
 218         sep = strchr(++field, ')');
 219         if (sep == NULL)
 220                 goto out_failure;
 221         size = sep - field;
 222         memcpy(comm_ev.comm, field, size++);
 223
 224         comm_ev.pid = pid;
 225         comm_ev.header.type = PERF_EVENT_COMM;
 226         size = ALIGN(size, sizeof(__u64));
 227         comm_ev.header.size = sizeof(comm_ev) - (sizeof(comm_ev.comm) - size);
 228
 229         if (!full) {
 230                 comm_ev.tid = pid;
 231
 232                 ret = write(output, &comm_ev, comm_ev.header.size);
 233                 if (ret < 0) {
 234                         perror("failed to write");
 235                         exit(-1);
 236                 }
 237                 return;
 238         }
 239
 240         snprintf(filename, sizeof(filename), "/proc/%d/task", pid);
 241
 242         tasks = opendir(filename);
 243         while (!readdir_r(tasks, &dirent, &next) && next) {
 244                 char *end;
 245                 pid = strtol(dirent.d_name, &end, 10);
 246                 if (*end)
 247                         continue;
 248
 249                 comm_ev.tid = pid;
 250
 251                 ret = write(output, &comm_ev, comm_ev.header.size);
 252                 if (ret < 0) {
 253                         perror("failed to write");
 254                         exit(-1);
 255                 }
 256         }
 257         closedir(tasks);
 258         return;
 259
 260 out_failure:
 261         fprintf(stderr, "couldn't get COMM and pgid, malformed %s\n",
 262                 filename);
 263         exit(EXIT_FAILURE);
 264 }
 265
 266 static void pid_synthesize_mmap_samples(pid_t pid)
 267 {
 268         char filename[PATH_MAX];
 269         FILE *fp;
 270
 271         snprintf(filename, sizeof(filename), "/proc/%d/maps", pid);
 272
 273         fp = fopen(filename, "r");
 274         if (fp == NULL) {
 275                 fprintf(stderr, "couldn't open %s\n", filename);
 276                 exit(EXIT_FAILURE);
 277         }
 278         while (1) {
 279                 char bf[BUFSIZ], *pbf = bf;
 280                 struct mmap_event mmap_ev = {
 281                         .header.type = PERF_EVENT_MMAP,
 282                 };
 283                 int n;
 284                 size_t size;
 285                 if (fgets(bf, sizeof(bf), fp) == NULL)
 286                         break;
 287
 288                 /* 00400000-0040c000 r-xp 00000000 fd:01 41038  /bin/cat */
 289                 n = hex2u64(pbf, &mmap_ev.start);
 290                 if (n < 0)
 291                         continue;
 292                 pbf += n + 1;
 293                 n = hex2u64(pbf, &mmap_ev.len);
 294                 if (n < 0)
 295                         continue;
 296                 pbf += n + 3;
 297                 if (*pbf == 'x') { /* vm_exec */
 298                         char *execname = strrchr(bf, ' ');
 299
 300                         if (execname == NULL || execname[1] != '/')
 301                                 continue;
 302
 303                         execname += 1;
 304                         size = strlen(execname);
 305                         execname[size - 1] = '\0'; /* Remove \n */
 306                         memcpy(mmap_ev.filename, execname, size);
 307                         size = ALIGN(size, sizeof(__u64));
 308                         mmap_ev.len -= mmap_ev.start;
 309                         mmap_ev.header.size = (sizeof(mmap_ev) -
 310                                                (sizeof(mmap_ev.filename) - size));
 311                         mmap_ev.pid = pid;
 312                         mmap_ev.tid = pid;
 313
 314                         if (write(output, &mmap_ev, mmap_ev.header.size) < 0) {
 315                                 perror("failed to write");
 316                                 exit(-1);
 317                         }
 318                 }
 319         }
 320
 321         fclose(fp);
 322 }
 323
 324 static void synthesize_samples(void)
 325 {
 326         DIR *proc;
 327         struct dirent dirent, *next;
 328
 329         proc = opendir("/proc");
 330
 331         while (!readdir_r(proc, &dirent, &next) && next) {
 332                 char *end;
 333                 pid_t pid;
 334
 335                 pid = strtol(dirent.d_name, &end, 10);
 336                 if (*end) /* only interested in proper numerical dirents */
 337                         continue;
 338
 339                 pid_synthesize_comm_event(pid, 1);
 340                 pid_synthesize_mmap_samples(pid);
 341         }
 342
 343         closedir(proc);
 344 }
 345
 346 static int group_fd;
 347
 348 static void create_counter(int counter, int cpu, pid_t pid)
 349 {
 350         struct perf_counter_attr *attr = attrs + counter;
 351         int track = 1;
 352
 353         attr->sample_type       = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 354         if (freq) {
 355                 attr->sample_type       |= PERF_SAMPLE_PERIOD;
 356                 attr->freq              = 1;
 357                 attr->sample_freq       = freq;
 358         }
 359         attr->mmap              = track;
 360         attr->comm              = track;
 361         attr->inherit           = (cpu < 0) && inherit;
 362         attr->disabled          = 1;
 363
 364         track = 0; /* only the first counter needs these */
 365
 366 try_again:
 367         fd[nr_cpu][counter] = sys_perf_counter_open(attr, pid, cpu, group_fd, 0);
 368
 369         if (fd[nr_cpu][counter] < 0) {
 370                 int err = errno;
 371
 372                 if (err == EPERM)
 373                         die("Permission error - are you root?\n");
 374
 375                 /*
 376                  * If it's cycles then fall back to hrtimer
 377                  * based cpu-clock-tick sw counter, which
 378                  * is always available even if no PMU support:
 379                  */
 380                 if (attr->type == PERF_TYPE_HARDWARE
 381                         && attr->config == PERF_COUNT_HW_CPU_CYCLES) {
 382
 383                         if (verbose)
 384                                 warning(" ... trying to fall back to cpu-clock-ticks\n");
 385                         attr->type = PERF_TYPE_SOFTWARE;
 386                         attr->config = PERF_COUNT_SW_CPU_CLOCK;
 387                         goto try_again;
 388                 }
 389                 printf("\n");
 390                 error("perfcounter syscall returned with %d (%s)\n",
 391                         fd[nr_cpu][counter], strerror(err));
 392                 die("No CONFIG_PERF_COUNTERS=y kernel support configured?\n");
 393                 exit(-1);
 394         }
 395
 396         assert(fd[nr_cpu][counter] >= 0);
 397         fcntl(fd[nr_cpu][counter], F_SETFL, O_NONBLOCK);
 398
 399         /*
 400          * First counter acts as the group leader:
 401          */
 402         if (group && group_fd == -1)
 403                 group_fd = fd[nr_cpu][counter];
 404
 405         event_array[nr_poll].fd = fd[nr_cpu][counter];
 406         event_array[nr_poll].events = POLLIN;
 407         nr_poll++;
 408
 409         mmap_array[nr_cpu][counter].counter = counter;
 410         mmap_array[nr_cpu][counter].prev = 0;
 411         mmap_array[nr_cpu][counter].mask = mmap_pages*page_size - 1;
 412         mmap_array[nr_cpu][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
 413                         PROT_READ, MAP_SHARED, fd[nr_cpu][counter], 0);
 414         if (mmap_array[nr_cpu][counter].base == MAP_FAILED) {
 415                 error("failed to mmap with %d (%s)\n", errno, strerror(errno));
 416                 exit(-1);
 417         }
 418
 419         ioctl(fd[nr_cpu][counter], PERF_COUNTER_IOC_ENABLE);
 420 }
 421
 422 static void open_counters(int cpu, pid_t pid)
 423 {
 424         int counter;
 425
 426         if (pid > 0) {
 427                 pid_synthesize_comm_event(pid, 0);
 428                 pid_synthesize_mmap_samples(pid);
 429         }
 430
 431         group_fd = -1;
 432         for (counter = 0; counter < nr_counters; counter++)
 433                 create_counter(counter, cpu, pid);
 434
 435         nr_cpu++;
 436 }
 437
 438 static int __cmd_record(int argc, const char **argv)
 439 {
 440         int i, counter;
 441         struct stat st;
 442         pid_t pid;
 443         int flags;
 444         int ret;
 445
 446         page_size = sysconf(_SC_PAGE_SIZE);
 447         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 448         assert(nr_cpus <= MAX_NR_CPUS);
 449         assert(nr_cpus >= 0);
 450
 451         if (!stat(output_name, &st) && !force && !append_file) {
 452                 fprintf(stderr, "Error, output file %s exists, use -A to append or -f to overwrite.\n",
 453                                 output_name);
 454                 exit(-1);
 455         }
 456
 457         flags = O_CREAT|O_RDWR;
 458         if (append_file)
 459                 flags |= O_APPEND;
 460         else
 461                 flags |= O_TRUNC;
 462
 463         output = open(output_name, flags, S_IRUSR|S_IWUSR);
 464         if (output < 0) {
 465                 perror("failed to create output file");
 466                 exit(-1);
 467         }
 468
 469         if (!system_wide) {
 470                 open_counters(-1, target_pid != -1 ? target_pid : getpid());
 471         } else for (i = 0; i < nr_cpus; i++)
 472                 open_counters(i, target_pid);
 473
 474         atexit(sig_atexit);
 475         signal(SIGCHLD, sig_handler);
 476         signal(SIGINT, sig_handler);
 477
 478         if (target_pid == -1 && argc) {
 479                 pid = fork();
 480                 if (pid < 0)
 481                         perror("failed to fork");
 482
 483                 if (!pid) {
 484                         if (execvp(argv[0], (char **)argv)) {
 485                                 perror(argv[0]);
 486                                 exit(-1);
 487                         }
 488                 }
 489         }
 490
 491         if (realtime_prio) {
 492                 struct sched_param param;
 493
 494                 param.sched_priority = realtime_prio;
 495                 if (sched_setscheduler(0, SCHED_FIFO, &param)) {
 496                         printf("Could not set realtime priority.\n");
 497                         exit(-1);
 498                 }
 499         }
 500
 501         if (system_wide)
 502                 synthesize_samples();
 503
 504         while (!done) {
 505                 int hits = samples;
 506
 507                 for (i = 0; i < nr_cpu; i++) {
 508                         for (counter = 0; counter < nr_counters; counter++)
 509                                 mmap_read(&mmap_array[i][counter]);
 510                 }
 511
 512                 if (hits == samples)
 513                         ret = poll(event_array, nr_poll, 100);
 514         }
 515
 516         /*
 517          * Approximate RIP event size: 24 bytes.
 518          */
 519         fprintf(stderr,
 520                 "[ perf record: Captured and wrote %.3f MB %s (~%lld samples) ]\n",
 521                 (double)bytes_written / 1024.0 / 1024.0,
 522                 output_name,
 523                 bytes_written / 24);
 524
 525         return 0;
 526 }
 527
 528 static const char * const record_usage[] = {
 529         "perf record [<options>] [<command>]",
 530         "perf record [<options>] -- <command> [<options>]",
 531         NULL
 532 };
 533
 534 static const struct option options[] = {
 535         OPT_CALLBACK('e', "event", NULL, "event",
 536                      "event selector. use 'perf list' to list available events",
 537                      parse_events),
 538         OPT_INTEGER('p', "pid", &target_pid,
 539                     "record events on existing pid"),
 540         OPT_INTEGER('r', "realtime", &realtime_prio,
 541                     "collect data with this RT SCHED_FIFO priority"),
 542         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 543                             "system-wide collection from all CPUs"),
 544         OPT_BOOLEAN('A', "append", &append_file,
 545                             "append to the output file to do incremental profiling"),
 546         OPT_BOOLEAN('f', "force", &force,
 547                         "overwrite existing data file"),
 548         OPT_LONG('c', "count", &default_interval,
 549                     "event period to sample"),
 550         OPT_STRING('o', "output", &output_name, "file",
 551                     "output file name"),
 552         OPT_BOOLEAN('i', "inherit", &inherit,
 553                     "child tasks inherit counters"),
 554         OPT_INTEGER('F', "freq", &freq,
 555                     "profile at this frequency"),
 556         OPT_INTEGER('m', "mmap-pages", &mmap_pages,
 557                     "number of mmap data pages"),
 558         OPT_BOOLEAN('v', "verbose", &verbose,
 559                     "be more verbose (show counter open errors, etc)"),
 560         OPT_END()
 561 };
 562
 563 int cmd_record(int argc, const char **argv, const char *prefix)
 564 {
 565         int counter;
 566
 567         argc = parse_options(argc, argv, options, record_usage, 0);
 568         if (!argc && target_pid == -1 && !system_wide)
 569                 usage_with_options(record_usage, options);
 570
 571         if (!nr_counters) {
 572                 nr_counters     = 1;
 573                 attrs[0].type   = PERF_TYPE_HARDWARE;
 574                 attrs[0].config = PERF_COUNT_HW_CPU_CYCLES;
 575         }
 576
 577         for (counter = 0; counter < nr_counters; counter++) {
 578                 if (attrs[counter].sample_period)
 579                         continue;
 580
 581                 attrs[counter].sample_period = default_interval;
 582         }
 583
 584         return __cmd_record(argc, argv);
 585 }