tools/perf/builtin-ftrace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * builtin-ftrace.c
   4  *
   5  * Copyright (c) 2013  LG Electronics,  Namhyung Kim <namhyung@kernel.org>
   6  * Copyright (c) 2020  Changbin Du <changbin.du@gmail.com>, significant enhancement.
   7  */
   8
   9 #include "builtin.h"
  10
  11 #include <errno.h>
  12 #include <unistd.h>
  13 #include <signal.h>
  14 #include <stdlib.h>
  15 #include <fcntl.h>
  16 #include <poll.h>
  17 #include <linux/capability.h>
  18 #include <linux/string.h>
  19
  20 #include "debug.h"
  21 #include <subcmd/pager.h>
  22 #include <subcmd/parse-options.h>
  23 #include <api/fs/tracing_path.h>
  24 #include "evlist.h"
  25 #include "target.h"
  26 #include "cpumap.h"
  27 #include "thread_map.h"
  28 #include "strfilter.h"
  29 #include "util/cap.h"
  30 #include "util/config.h"
  31 #include "util/units.h"
  32 #include "util/parse-sublevel-options.h"
  33
  34 #define DEFAULT_TRACER  "function_graph"
  35
  36 struct perf_ftrace {
  37         struct evlist           *evlist;
  38         struct target           target;
  39         const char              *tracer;
  40         struct list_head        filters;
  41         struct list_head        notrace;
  42         struct list_head        graph_funcs;
  43         struct list_head        nograph_funcs;
  44         int                     graph_depth;
  45         unsigned long           percpu_buffer_size;
  46         bool                    inherit;
  47         int                     func_stack_trace;
  48         int                     func_irq_info;
  49         int                     graph_nosleep_time;
  50         int                     graph_noirqs;
  51         int                     graph_verbose;
  52         int                     graph_thresh;
  53         unsigned int            initial_delay;
  54 };
  55
  56 struct filter_entry {
  57         struct list_head        list;
  58         char                    name[];
  59 };
  60
  61 static volatile int workload_exec_errno;
  62 static bool done;
  63
  64 static void sig_handler(int sig __maybe_unused)
  65 {
  66         done = true;
  67 }
  68
  69 /*
  70  * evlist__prepare_workload will send a SIGUSR1 if the fork fails, since
  71  * we asked by setting its exec_error to the function below,
  72  * ftrace__workload_exec_failed_signal.
  73  *
  74  * XXX We need to handle this more appropriately, emitting an error, etc.
  75  */
  76 static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,
  77                                                 siginfo_t *info __maybe_unused,
  78                                                 void *ucontext __maybe_unused)
  79 {
  80         workload_exec_errno = info->si_value.sival_int;
  81         done = true;
  82 }
  83
  84 static int __write_tracing_file(const char *name, const char *val, bool append)
  85 {
  86         char *file;
  87         int fd, ret = -1;
  88         ssize_t size = strlen(val);
  89         int flags = O_WRONLY;
  90         char errbuf[512];
  91         char *val_copy;
  92
  93         file = get_tracing_file(name);
  94         if (!file) {
  95                 pr_debug("cannot get tracing file: %s\n", name);
  96                 return -1;
  97         }
  98
  99         if (append)
 100                 flags |= O_APPEND;
 101         else
 102                 flags |= O_TRUNC;
 103
 104         fd = open(file, flags);
 105         if (fd < 0) {
 106                 pr_debug("cannot open tracing file: %s: %s\n",
 107                          name, str_error_r(errno, errbuf, sizeof(errbuf)));
 108                 goto out;
 109         }
 110
 111         /*
 112          * Copy the original value and append a '\n'. Without this,
 113          * the kernel can hide possible errors.
 114          */
 115         val_copy = strdup(val);
 116         if (!val_copy)
 117                 goto out_close;
 118         val_copy[size] = '\n';
 119
 120         if (write(fd, val_copy, size + 1) == size + 1)
 121                 ret = 0;
 122         else
 123                 pr_debug("write '%s' to tracing/%s failed: %s\n",
 124                          val, name, str_error_r(errno, errbuf, sizeof(errbuf)));
 125
 126         free(val_copy);
 127 out_close:
 128         close(fd);
 129 out:
 130         put_tracing_file(file);
 131         return ret;
 132 }
 133
 134 static int write_tracing_file(const char *name, const char *val)
 135 {
 136         return __write_tracing_file(name, val, false);
 137 }
 138
 139 static int append_tracing_file(const char *name, const char *val)
 140 {
 141         return __write_tracing_file(name, val, true);
 142 }
 143
 144 static int read_tracing_file_to_stdout(const char *name)
 145 {
 146         char buf[4096];
 147         char *file;
 148         int fd;
 149         int ret = -1;
 150
 151         file = get_tracing_file(name);
 152         if (!file) {
 153                 pr_debug("cannot get tracing file: %s\n", name);
 154                 return -1;
 155         }
 156
 157         fd = open(file, O_RDONLY);
 158         if (fd < 0) {
 159                 pr_debug("cannot open tracing file: %s: %s\n",
 160                          name, str_error_r(errno, buf, sizeof(buf)));
 161                 goto out;
 162         }
 163
 164         /* read contents to stdout */
 165         while (true) {
 166                 int n = read(fd, buf, sizeof(buf));
 167                 if (n == 0)
 168                         break;
 169                 else if (n < 0)
 170                         goto out_close;
 171
 172                 if (fwrite(buf, n, 1, stdout) != 1)
 173                         goto out_close;
 174         }
 175         ret = 0;
 176
 177 out_close:
 178         close(fd);
 179 out:
 180         put_tracing_file(file);
 181         return ret;
 182 }
 183
 184 static int read_tracing_file_by_line(const char *name,
 185                                      void (*cb)(char *str, void *arg),
 186                                      void *cb_arg)
 187 {
 188         char *line = NULL;
 189         size_t len = 0;
 190         char *file;
 191         FILE *fp;
 192
 193         file = get_tracing_file(name);
 194         if (!file) {
 195                 pr_debug("cannot get tracing file: %s\n", name);
 196                 return -1;
 197         }
 198
 199         fp = fopen(file, "r");
 200         if (fp == NULL) {
 201                 pr_debug("cannot open tracing file: %s\n", name);
 202                 put_tracing_file(file);
 203                 return -1;
 204         }
 205
 206         while (getline(&line, &len, fp) != -1) {
 207                 cb(line, cb_arg);
 208         }
 209
 210         if (line)
 211                 free(line);
 212
 213         fclose(fp);
 214         put_tracing_file(file);
 215         return 0;
 216 }
 217
 218 static int write_tracing_file_int(const char *name, int value)
 219 {
 220         char buf[16];
 221
 222         snprintf(buf, sizeof(buf), "%d", value);
 223         if (write_tracing_file(name, buf) < 0)
 224                 return -1;
 225
 226         return 0;
 227 }
 228
 229 static int write_tracing_option_file(const char *name, const char *val)
 230 {
 231         char *file;
 232         int ret;
 233
 234         if (asprintf(&file, "options/%s", name) < 0)
 235                 return -1;
 236
 237         ret = __write_tracing_file(file, val, false);
 238         free(file);
 239         return ret;
 240 }
 241
 242 static int reset_tracing_cpu(void);
 243 static void reset_tracing_filters(void);
 244
 245 static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused)
 246 {
 247         write_tracing_option_file("function-fork", "0");
 248         write_tracing_option_file("func_stack_trace", "0");
 249         write_tracing_option_file("sleep-time", "1");
 250         write_tracing_option_file("funcgraph-irqs", "1");
 251         write_tracing_option_file("funcgraph-proc", "0");
 252         write_tracing_option_file("funcgraph-abstime", "0");
 253         write_tracing_option_file("latency-format", "0");
 254         write_tracing_option_file("irq-info", "0");
 255 }
 256
 257 static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
 258 {
 259         if (write_tracing_file("tracing_on", "0") < 0)
 260                 return -1;
 261
 262         if (write_tracing_file("current_tracer", "nop") < 0)
 263                 return -1;
 264
 265         if (write_tracing_file("set_ftrace_pid", " ") < 0)
 266                 return -1;
 267
 268         if (reset_tracing_cpu() < 0)
 269                 return -1;
 270
 271         if (write_tracing_file("max_graph_depth", "0") < 0)
 272                 return -1;
 273
 274         if (write_tracing_file("tracing_thresh", "0") < 0)
 275                 return -1;
 276
 277         reset_tracing_filters();
 278         reset_tracing_options(ftrace);
 279         return 0;
 280 }
 281
 282 static int set_tracing_pid(struct perf_ftrace *ftrace)
 283 {
 284         int i;
 285         char buf[16];
 286
 287         if (target__has_cpu(&ftrace->target))
 288                 return 0;
 289
 290         for (i = 0; i < perf_thread_map__nr(ftrace->evlist->core.threads); i++) {
 291                 scnprintf(buf, sizeof(buf), "%d",
 292                           ftrace->evlist->core.threads->map[i]);
 293                 if (append_tracing_file("set_ftrace_pid", buf) < 0)
 294                         return -1;
 295         }
 296         return 0;
 297 }
 298
 299 static int set_tracing_cpumask(struct perf_cpu_map *cpumap)
 300 {
 301         char *cpumask;
 302         size_t mask_size;
 303         int ret;
 304         int last_cpu;
 305
 306         last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);
 307         mask_size = last_cpu / 4 + 2; /* one more byte for EOS */
 308         mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */
 309
 310         cpumask = malloc(mask_size);
 311         if (cpumask == NULL) {
 312                 pr_debug("failed to allocate cpu mask\n");
 313                 return -1;
 314         }
 315
 316         cpu_map__snprint_mask(cpumap, cpumask, mask_size);
 317
 318         ret = write_tracing_file("tracing_cpumask", cpumask);
 319
 320         free(cpumask);
 321         return ret;
 322 }
 323
 324 static int set_tracing_cpu(struct perf_ftrace *ftrace)
 325 {
 326         struct perf_cpu_map *cpumap = ftrace->evlist->core.cpus;
 327
 328         if (!target__has_cpu(&ftrace->target))
 329                 return 0;
 330
 331         return set_tracing_cpumask(cpumap);
 332 }
 333
 334 static int set_tracing_func_stack_trace(struct perf_ftrace *ftrace)
 335 {
 336         if (!ftrace->func_stack_trace)
 337                 return 0;
 338
 339         if (write_tracing_option_file("func_stack_trace", "1") < 0)
 340                 return -1;
 341
 342         return 0;
 343 }
 344
 345 static int set_tracing_func_irqinfo(struct perf_ftrace *ftrace)
 346 {
 347         if (!ftrace->func_irq_info)
 348                 return 0;
 349
 350         if (write_tracing_option_file("irq-info", "1") < 0)
 351                 return -1;
 352
 353         return 0;
 354 }
 355
 356 static int reset_tracing_cpu(void)
 357 {
 358         struct perf_cpu_map *cpumap = perf_cpu_map__new(NULL);
 359         int ret;
 360
 361         ret = set_tracing_cpumask(cpumap);
 362         perf_cpu_map__put(cpumap);
 363         return ret;
 364 }
 365
 366 static int __set_tracing_filter(const char *filter_file, struct list_head *funcs)
 367 {
 368         struct filter_entry *pos;
 369
 370         list_for_each_entry(pos, funcs, list) {
 371                 if (append_tracing_file(filter_file, pos->name) < 0)
 372                         return -1;
 373         }
 374
 375         return 0;
 376 }
 377
 378 static int set_tracing_filters(struct perf_ftrace *ftrace)
 379 {
 380         int ret;
 381
 382         ret = __set_tracing_filter("set_ftrace_filter", &ftrace->filters);
 383         if (ret < 0)
 384                 return ret;
 385
 386         ret = __set_tracing_filter("set_ftrace_notrace", &ftrace->notrace);
 387         if (ret < 0)
 388                 return ret;
 389
 390         ret = __set_tracing_filter("set_graph_function", &ftrace->graph_funcs);
 391         if (ret < 0)
 392                 return ret;
 393
 394         /* old kernels do not have this filter */
 395         __set_tracing_filter("set_graph_notrace", &ftrace->nograph_funcs);
 396
 397         return ret;
 398 }
 399
 400 static void reset_tracing_filters(void)
 401 {
 402         write_tracing_file("set_ftrace_filter", " ");
 403         write_tracing_file("set_ftrace_notrace", " ");
 404         write_tracing_file("set_graph_function", " ");
 405         write_tracing_file("set_graph_notrace", " ");
 406 }
 407
 408 static int set_tracing_depth(struct perf_ftrace *ftrace)
 409 {
 410         if (ftrace->graph_depth == 0)
 411                 return 0;
 412
 413         if (ftrace->graph_depth < 0) {
 414                 pr_err("invalid graph depth: %d\n", ftrace->graph_depth);
 415                 return -1;
 416         }
 417
 418         if (write_tracing_file_int("max_graph_depth", ftrace->graph_depth) < 0)
 419                 return -1;
 420
 421         return 0;
 422 }
 423
 424 static int set_tracing_percpu_buffer_size(struct perf_ftrace *ftrace)
 425 {
 426         int ret;
 427
 428         if (ftrace->percpu_buffer_size == 0)
 429                 return 0;
 430
 431         ret = write_tracing_file_int("buffer_size_kb",
 432                                      ftrace->percpu_buffer_size / 1024);
 433         if (ret < 0)
 434                 return ret;
 435
 436         return 0;
 437 }
 438
 439 static int set_tracing_trace_inherit(struct perf_ftrace *ftrace)
 440 {
 441         if (!ftrace->inherit)
 442                 return 0;
 443
 444         if (write_tracing_option_file("function-fork", "1") < 0)
 445                 return -1;
 446
 447         return 0;
 448 }
 449
 450 static int set_tracing_sleep_time(struct perf_ftrace *ftrace)
 451 {
 452         if (!ftrace->graph_nosleep_time)
 453                 return 0;
 454
 455         if (write_tracing_option_file("sleep-time", "0") < 0)
 456                 return -1;
 457
 458         return 0;
 459 }
 460
 461 static int set_tracing_funcgraph_irqs(struct perf_ftrace *ftrace)
 462 {
 463         if (!ftrace->graph_noirqs)
 464                 return 0;
 465
 466         if (write_tracing_option_file("funcgraph-irqs", "0") < 0)
 467                 return -1;
 468
 469         return 0;
 470 }
 471
 472 static int set_tracing_funcgraph_verbose(struct perf_ftrace *ftrace)
 473 {
 474         if (!ftrace->graph_verbose)
 475                 return 0;
 476
 477         if (write_tracing_option_file("funcgraph-proc", "1") < 0)
 478                 return -1;
 479
 480         if (write_tracing_option_file("funcgraph-abstime", "1") < 0)
 481                 return -1;
 482
 483         if (write_tracing_option_file("latency-format", "1") < 0)
 484                 return -1;
 485
 486         return 0;
 487 }
 488
 489 static int set_tracing_thresh(struct perf_ftrace *ftrace)
 490 {
 491         int ret;
 492
 493         if (ftrace->graph_thresh == 0)
 494                 return 0;
 495
 496         ret = write_tracing_file_int("tracing_thresh", ftrace->graph_thresh);
 497         if (ret < 0)
 498                 return ret;
 499
 500         return 0;
 501 }
 502
 503 static int set_tracing_options(struct perf_ftrace *ftrace)
 504 {
 505         if (set_tracing_pid(ftrace) < 0) {
 506                 pr_err("failed to set ftrace pid\n");
 507                 return -1;
 508         }
 509
 510         if (set_tracing_cpu(ftrace) < 0) {
 511                 pr_err("failed to set tracing cpumask\n");
 512                 return -1;
 513         }
 514
 515         if (set_tracing_func_stack_trace(ftrace) < 0) {
 516                 pr_err("failed to set tracing option func_stack_trace\n");
 517                 return -1;
 518         }
 519
 520         if (set_tracing_func_irqinfo(ftrace) < 0) {
 521                 pr_err("failed to set tracing option irq-info\n");
 522                 return -1;
 523         }
 524
 525         if (set_tracing_filters(ftrace) < 0) {
 526                 pr_err("failed to set tracing filters\n");
 527                 return -1;
 528         }
 529
 530         if (set_tracing_depth(ftrace) < 0) {
 531                 pr_err("failed to set graph depth\n");
 532                 return -1;
 533         }
 534
 535         if (set_tracing_percpu_buffer_size(ftrace) < 0) {
 536                 pr_err("failed to set tracing per-cpu buffer size\n");
 537                 return -1;
 538         }
 539
 540         if (set_tracing_trace_inherit(ftrace) < 0) {
 541                 pr_err("failed to set tracing option function-fork\n");
 542                 return -1;
 543         }
 544
 545         if (set_tracing_sleep_time(ftrace) < 0) {
 546                 pr_err("failed to set tracing option sleep-time\n");
 547                 return -1;
 548         }
 549
 550         if (set_tracing_funcgraph_irqs(ftrace) < 0) {
 551                 pr_err("failed to set tracing option funcgraph-irqs\n");
 552                 return -1;
 553         }
 554
 555         if (set_tracing_funcgraph_verbose(ftrace) < 0) {
 556                 pr_err("failed to set tracing option funcgraph-proc/funcgraph-abstime\n");
 557                 return -1;
 558         }
 559
 560         if (set_tracing_thresh(ftrace) < 0) {
 561                 pr_err("failed to set tracing thresh\n");
 562                 return -1;
 563         }
 564
 565         return 0;
 566 }
 567
 568 static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 569 {
 570         char *trace_file;
 571         int trace_fd;
 572         char buf[4096];
 573         struct pollfd pollfd = {
 574                 .events = POLLIN,
 575         };
 576
 577         if (!(perf_cap__capable(CAP_PERFMON) ||
 578               perf_cap__capable(CAP_SYS_ADMIN))) {
 579                 pr_err("ftrace only works for %s!\n",
 580 #ifdef HAVE_LIBCAP_SUPPORT
 581                 "users with the CAP_PERFMON or CAP_SYS_ADMIN capability"
 582 #else
 583                 "root"
 584 #endif
 585                 );
 586                 return -1;
 587         }
 588
 589         signal(SIGINT, sig_handler);
 590         signal(SIGUSR1, sig_handler);
 591         signal(SIGCHLD, sig_handler);
 592         signal(SIGPIPE, sig_handler);
 593
 594         if (reset_tracing_files(ftrace) < 0) {
 595                 pr_err("failed to reset ftrace\n");
 596                 goto out;
 597         }
 598
 599         /* reset ftrace buffer */
 600         if (write_tracing_file("trace", "0") < 0)
 601                 goto out;
 602
 603         if (argc && evlist__prepare_workload(ftrace->evlist, &ftrace->target, argv, false,
 604                                              ftrace__workload_exec_failed_signal) < 0) {
 605                 goto out;
 606         }
 607
 608         if (set_tracing_options(ftrace) < 0)
 609                 goto out_reset;
 610
 611         if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
 612                 pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
 613                 goto out_reset;
 614         }
 615
 616         setup_pager();
 617
 618         trace_file = get_tracing_file("trace_pipe");
 619         if (!trace_file) {
 620                 pr_err("failed to open trace_pipe\n");
 621                 goto out_reset;
 622         }
 623
 624         trace_fd = open(trace_file, O_RDONLY);
 625
 626         put_tracing_file(trace_file);
 627
 628         if (trace_fd < 0) {
 629                 pr_err("failed to open trace_pipe\n");
 630                 goto out_reset;
 631         }
 632
 633         fcntl(trace_fd, F_SETFL, O_NONBLOCK);
 634         pollfd.fd = trace_fd;
 635
 636         /* display column headers */
 637         read_tracing_file_to_stdout("trace");
 638
 639         if (!ftrace->initial_delay) {
 640                 if (write_tracing_file("tracing_on", "1") < 0) {
 641                         pr_err("can't enable tracing\n");
 642                         goto out_close_fd;
 643                 }
 644         }
 645
 646         evlist__start_workload(ftrace->evlist);
 647
 648         if (ftrace->initial_delay) {
 649                 usleep(ftrace->initial_delay * 1000);
 650                 if (write_tracing_file("tracing_on", "1") < 0) {
 651                         pr_err("can't enable tracing\n");
 652                         goto out_close_fd;
 653                 }
 654         }
 655
 656         while (!done) {
 657                 if (poll(&pollfd, 1, -1) < 0)
 658                         break;
 659
 660                 if (pollfd.revents & POLLIN) {
 661                         int n = read(trace_fd, buf, sizeof(buf));
 662                         if (n < 0)
 663                                 break;
 664                         if (fwrite(buf, n, 1, stdout) != 1)
 665                                 break;
 666                 }
 667         }
 668
 669         write_tracing_file("tracing_on", "0");
 670
 671         if (workload_exec_errno) {
 672                 const char *emsg = str_error_r(workload_exec_errno, buf, sizeof(buf));
 673                 /* flush stdout first so below error msg appears at the end. */
 674                 fflush(stdout);
 675                 pr_err("workload failed: %s\n", emsg);
 676                 goto out_close_fd;
 677         }
 678
 679         /* read remaining buffer contents */
 680         while (true) {
 681                 int n = read(trace_fd, buf, sizeof(buf));
 682                 if (n <= 0)
 683                         break;
 684                 if (fwrite(buf, n, 1, stdout) != 1)
 685                         break;
 686         }
 687
 688 out_close_fd:
 689         close(trace_fd);
 690 out_reset:
 691         reset_tracing_files(ftrace);
 692 out:
 693         return (done && !workload_exec_errno) ? 0 : -1;
 694 }
 695
 696 static int perf_ftrace_config(const char *var, const char *value, void *cb)
 697 {
 698         struct perf_ftrace *ftrace = cb;
 699
 700         if (!strstarts(var, "ftrace."))
 701                 return 0;
 702
 703         if (strcmp(var, "ftrace.tracer"))
 704                 return -1;
 705
 706         if (!strcmp(value, "function_graph") ||
 707             !strcmp(value, "function")) {
 708                 ftrace->tracer = value;
 709                 return 0;
 710         }
 711
 712         pr_err("Please select \"function_graph\" (default) or \"function\"\n");
 713         return -1;
 714 }
 715
 716 static void list_function_cb(char *str, void *arg)
 717 {
 718         struct strfilter *filter = (struct strfilter *)arg;
 719
 720         if (strfilter__compare(filter, str))
 721                 printf("%s", str);
 722 }
 723
 724 static int opt_list_avail_functions(const struct option *opt __maybe_unused,
 725                                     const char *str, int unset)
 726 {
 727         struct strfilter *filter;
 728         const char *err = NULL;
 729         int ret;
 730
 731         if (unset || !str)
 732                 return -1;
 733
 734         filter = strfilter__new(str, &err);
 735         if (!filter)
 736                 return err ? -EINVAL : -ENOMEM;
 737
 738         ret = strfilter__or(filter, str, &err);
 739         if (ret == -EINVAL) {
 740                 pr_err("Filter parse error at %td.\n", err - str + 1);
 741                 pr_err("Source: \"%s\"\n", str);
 742                 pr_err("         %*c\n", (int)(err - str + 1), '^');
 743                 strfilter__delete(filter);
 744                 return ret;
 745         }
 746
 747         ret = read_tracing_file_by_line("available_filter_functions",
 748                                         list_function_cb, filter);
 749         strfilter__delete(filter);
 750         if (ret < 0)
 751                 return ret;
 752
 753         exit(0);
 754 }
 755
 756 static int parse_filter_func(const struct option *opt, const char *str,
 757                              int unset __maybe_unused)
 758 {
 759         struct list_head *head = opt->value;
 760         struct filter_entry *entry;
 761
 762         entry = malloc(sizeof(*entry) + strlen(str) + 1);
 763         if (entry == NULL)
 764                 return -ENOMEM;
 765
 766         strcpy(entry->name, str);
 767         list_add_tail(&entry->list, head);
 768
 769         return 0;
 770 }
 771
 772 static void delete_filter_func(struct list_head *head)
 773 {
 774         struct filter_entry *pos, *tmp;
 775
 776         list_for_each_entry_safe(pos, tmp, head, list) {
 777                 list_del_init(&pos->list);
 778                 free(pos);
 779         }
 780 }
 781
 782 static int parse_buffer_size(const struct option *opt,
 783                              const char *str, int unset)
 784 {
 785         unsigned long *s = (unsigned long *)opt->value;
 786         static struct parse_tag tags_size[] = {
 787                 { .tag  = 'B', .mult = 1       },
 788                 { .tag  = 'K', .mult = 1 << 10 },
 789                 { .tag  = 'M', .mult = 1 << 20 },
 790                 { .tag  = 'G', .mult = 1 << 30 },
 791                 { .tag  = 0 },
 792         };
 793         unsigned long val;
 794
 795         if (unset) {
 796                 *s = 0;
 797                 return 0;
 798         }
 799
 800         val = parse_tag_value(str, tags_size);
 801         if (val != (unsigned long) -1) {
 802                 if (val < 1024) {
 803                         pr_err("buffer size too small, must larger than 1KB.");
 804                         return -1;
 805                 }
 806                 *s = val;
 807                 return 0;
 808         }
 809
 810         return -1;
 811 }
 812
 813 static int parse_func_tracer_opts(const struct option *opt,
 814                                   const char *str, int unset)
 815 {
 816         int ret;
 817         struct perf_ftrace *ftrace = (struct perf_ftrace *) opt->value;
 818         struct sublevel_option func_tracer_opts[] = {
 819                 { .name = "call-graph", .value_ptr = &ftrace->func_stack_trace },
 820                 { .name = "irq-info",   .value_ptr = &ftrace->func_irq_info },
 821                 { .name = NULL, }
 822         };
 823
 824         if (unset)
 825                 return 0;
 826
 827         ret = perf_parse_sublevel_options(str, func_tracer_opts);
 828         if (ret)
 829                 return ret;
 830
 831         return 0;
 832 }
 833
 834 static int parse_graph_tracer_opts(const struct option *opt,
 835                                   const char *str, int unset)
 836 {
 837         int ret;
 838         struct perf_ftrace *ftrace = (struct perf_ftrace *) opt->value;
 839         struct sublevel_option graph_tracer_opts[] = {
 840                 { .name = "nosleep-time",       .value_ptr = &ftrace->graph_nosleep_time },
 841                 { .name = "noirqs",             .value_ptr = &ftrace->graph_noirqs },
 842                 { .name = "verbose",            .value_ptr = &ftrace->graph_verbose },
 843                 { .name = "thresh",             .value_ptr = &ftrace->graph_thresh },
 844                 { .name = "depth",              .value_ptr = &ftrace->graph_depth },
 845                 { .name = NULL, }
 846         };
 847
 848         if (unset)
 849                 return 0;
 850
 851         ret = perf_parse_sublevel_options(str, graph_tracer_opts);
 852         if (ret)
 853                 return ret;
 854
 855         return 0;
 856 }
 857
 858 static void select_tracer(struct perf_ftrace *ftrace)
 859 {
 860         bool graph = !list_empty(&ftrace->graph_funcs) ||
 861                      !list_empty(&ftrace->nograph_funcs);
 862         bool func = !list_empty(&ftrace->filters) ||
 863                     !list_empty(&ftrace->notrace);
 864
 865         /* The function_graph has priority over function tracer. */
 866         if (graph)
 867                 ftrace->tracer = "function_graph";
 868         else if (func)
 869                 ftrace->tracer = "function";
 870         /* Otherwise, the default tracer is used. */
 871
 872         pr_debug("%s tracer is used\n", ftrace->tracer);
 873 }
 874
 875 int cmd_ftrace(int argc, const char **argv)
 876 {
 877         int ret;
 878         struct perf_ftrace ftrace = {
 879                 .tracer = DEFAULT_TRACER,
 880                 .target = { .uid = UINT_MAX, },
 881         };
 882         const char * const ftrace_usage[] = {
 883                 "perf ftrace [<options>] [<command>]",
 884                 "perf ftrace [<options>] -- <command> [<options>]",
 885                 NULL
 886         };
 887         const struct option ftrace_options[] = {
 888         OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
 889                    "Tracer to use: function_graph(default) or function"),
 890         OPT_CALLBACK_DEFAULT('F', "funcs", NULL, "[FILTER]",
 891                              "Show available functions to filter",
 892                              opt_list_avail_functions, "*"),
 893         OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
 894                    "Trace on existing process id"),
 895         /* TODO: Add short option -t after -t/--tracer can be removed. */
 896         OPT_STRING(0, "tid", &ftrace.target.tid, "tid",
 897                    "Trace on existing thread id (exclusive to --pid)"),
 898         OPT_INCR('v', "verbose", &verbose,
 899                  "Be more verbose"),
 900         OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
 901                     "System-wide collection from all CPUs"),
 902         OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
 903                     "List of cpus to monitor"),
 904         OPT_CALLBACK('T', "trace-funcs", &ftrace.filters, "func",
 905                      "Trace given functions using function tracer",
 906                      parse_filter_func),
 907         OPT_CALLBACK('N', "notrace-funcs", &ftrace.notrace, "func",
 908                      "Do not trace given functions", parse_filter_func),
 909         OPT_CALLBACK(0, "func-opts", &ftrace, "options",
 910                      "Function tracer options, available options: call-graph,irq-info",
 911                      parse_func_tracer_opts),
 912         OPT_CALLBACK('G', "graph-funcs", &ftrace.graph_funcs, "func",
 913                      "Trace given functions using function_graph tracer",
 914                      parse_filter_func),
 915         OPT_CALLBACK('g', "nograph-funcs", &ftrace.nograph_funcs, "func",
 916                      "Set nograph filter on given functions", parse_filter_func),
 917         OPT_CALLBACK(0, "graph-opts", &ftrace, "options",
 918                      "Graph tracer options, available options: nosleep-time,noirqs,verbose,thresh=<n>,depth=<n>",
 919                      parse_graph_tracer_opts),
 920         OPT_CALLBACK('m', "buffer-size", &ftrace.percpu_buffer_size, "size",
 921                      "Size of per cpu buffer, needs to use a B, K, M or G suffix.", parse_buffer_size),
 922         OPT_BOOLEAN(0, "inherit", &ftrace.inherit,
 923                     "Trace children processes"),
 924         OPT_UINTEGER('D', "delay", &ftrace.initial_delay,
 925                      "Number of milliseconds to wait before starting tracing after program start"),
 926         OPT_END()
 927         };
 928
 929         INIT_LIST_HEAD(&ftrace.filters);
 930         INIT_LIST_HEAD(&ftrace.notrace);
 931         INIT_LIST_HEAD(&ftrace.graph_funcs);
 932         INIT_LIST_HEAD(&ftrace.nograph_funcs);
 933
 934         ret = perf_config(perf_ftrace_config, &ftrace);
 935         if (ret < 0)
 936                 return -1;
 937
 938         argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
 939                             PARSE_OPT_STOP_AT_NON_OPTION);
 940         if (!argc && target__none(&ftrace.target))
 941                 ftrace.target.system_wide = true;
 942
 943         select_tracer(&ftrace);
 944
 945         ret = target__validate(&ftrace.target);
 946         if (ret) {
 947                 char errbuf[512];
 948
 949                 target__strerror(&ftrace.target, ret, errbuf, 512);
 950                 pr_err("%s\n", errbuf);
 951                 goto out_delete_filters;
 952         }
 953
 954         ftrace.evlist = evlist__new();
 955         if (ftrace.evlist == NULL) {
 956                 ret = -ENOMEM;
 957                 goto out_delete_filters;
 958         }
 959
 960         ret = evlist__create_maps(ftrace.evlist, &ftrace.target);
 961         if (ret < 0)
 962                 goto out_delete_evlist;
 963
 964         ret = __cmd_ftrace(&ftrace, argc, argv);
 965
 966 out_delete_evlist:
 967         evlist__delete(ftrace.evlist);
 968
 969 out_delete_filters:
 970         delete_filter_func(&ftrace.filters);
 971         delete_filter_func(&ftrace.notrace);
 972         delete_filter_func(&ftrace.graph_funcs);
 973         delete_filter_func(&ftrace.nograph_funcs);
 974
 975         return ret;
 976 }