tools/perf/builtin-ftrace.c

   1 /*
   2  * builtin-ftrace.c
   3  *
   4  * Copyright (c) 2013  LG Electronics,  Namhyung Kim <namhyung@kernel.org>
   5  *
   6  * Released under the GPL v2.
   7  */
   8
   9 #include "builtin.h"
  10 #include "perf.h"
  11
  12 #include <errno.h>
  13 #include <unistd.h>
  14 #include <signal.h>
  15 #include <fcntl.h>
  16 #include <poll.h>
  17
  18 #include "debug.h"
  19 #include <subcmd/parse-options.h>
  20 #include <api/fs/tracing_path.h>
  21 #include "evlist.h"
  22 #include "target.h"
  23 #include "cpumap.h"
  24 #include "thread_map.h"
  25 #include "util/config.h"
  26
  27
  28 #define DEFAULT_TRACER  "function_graph"
  29
  30 struct perf_ftrace {
  31         struct perf_evlist      *evlist;
  32         struct target           target;
  33         const char              *tracer;
  34         struct list_head        filters;
  35         struct list_head        notrace;
  36         struct list_head        graph_funcs;
  37         struct list_head        nograph_funcs;
  38         int                     graph_depth;
  39 };
  40
  41 struct filter_entry {
  42         struct list_head        list;
  43         char                    name[];
  44 };
  45
  46 static bool done;
  47
  48 static void sig_handler(int sig __maybe_unused)
  49 {
  50         done = true;
  51 }
  52
  53 /*
  54  * perf_evlist__prepare_workload will send a SIGUSR1 if the fork fails, since
  55  * we asked by setting its exec_error to the function below,
  56  * ftrace__workload_exec_failed_signal.
  57  *
  58  * XXX We need to handle this more appropriately, emitting an error, etc.
  59  */
  60 static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,
  61                                                 siginfo_t *info __maybe_unused,
  62                                                 void *ucontext __maybe_unused)
  63 {
  64         /* workload_exec_errno = info->si_value.sival_int; */
  65         done = true;
  66 }
  67
  68 static int __write_tracing_file(const char *name, const char *val, bool append)
  69 {
  70         char *file;
  71         int fd, ret = -1;
  72         ssize_t size = strlen(val);
  73         int flags = O_WRONLY;
  74         char errbuf[512];
  75         char *val_copy;
  76
  77         file = get_tracing_file(name);
  78         if (!file) {
  79                 pr_debug("cannot get tracing file: %s\n", name);
  80                 return -1;
  81         }
  82
  83         if (append)
  84                 flags |= O_APPEND;
  85         else
  86                 flags |= O_TRUNC;
  87
  88         fd = open(file, flags);
  89         if (fd < 0) {
  90                 pr_debug("cannot open tracing file: %s: %s\n",
  91                          name, str_error_r(errno, errbuf, sizeof(errbuf)));
  92                 goto out;
  93         }
  94
  95         /*
  96          * Copy the original value and append a '\n'. Without this,
  97          * the kernel can hide possible errors.
  98          */
  99         val_copy = strdup(val);
 100         if (!val_copy)
 101                 goto out_close;
 102         val_copy[size] = '\n';
 103
 104         if (write(fd, val_copy, size + 1) == size + 1)
 105                 ret = 0;
 106         else
 107                 pr_debug("write '%s' to tracing/%s failed: %s\n",
 108                          val, name, str_error_r(errno, errbuf, sizeof(errbuf)));
 109
 110         free(val_copy);
 111 out_close:
 112         close(fd);
 113 out:
 114         put_tracing_file(file);
 115         return ret;
 116 }
 117
 118 static int write_tracing_file(const char *name, const char *val)
 119 {
 120         return __write_tracing_file(name, val, false);
 121 }
 122
 123 static int append_tracing_file(const char *name, const char *val)
 124 {
 125         return __write_tracing_file(name, val, true);
 126 }
 127
 128 static int reset_tracing_cpu(void);
 129 static void reset_tracing_filters(void);
 130
 131 static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
 132 {
 133         if (write_tracing_file("tracing_on", "0") < 0)
 134                 return -1;
 135
 136         if (write_tracing_file("current_tracer", "nop") < 0)
 137                 return -1;
 138
 139         if (write_tracing_file("set_ftrace_pid", " ") < 0)
 140                 return -1;
 141
 142         if (reset_tracing_cpu() < 0)
 143                 return -1;
 144
 145         if (write_tracing_file("max_graph_depth", "0") < 0)
 146                 return -1;
 147
 148         reset_tracing_filters();
 149         return 0;
 150 }
 151
 152 static int set_tracing_pid(struct perf_ftrace *ftrace)
 153 {
 154         int i;
 155         char buf[16];
 156
 157         if (target__has_cpu(&ftrace->target))
 158                 return 0;
 159
 160         for (i = 0; i < thread_map__nr(ftrace->evlist->threads); i++) {
 161                 scnprintf(buf, sizeof(buf), "%d",
 162                           ftrace->evlist->threads->map[i]);
 163                 if (append_tracing_file("set_ftrace_pid", buf) < 0)
 164                         return -1;
 165         }
 166         return 0;
 167 }
 168
 169 static int set_tracing_cpumask(struct cpu_map *cpumap)
 170 {
 171         char *cpumask;
 172         size_t mask_size;
 173         int ret;
 174         int last_cpu;
 175
 176         last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);
 177         mask_size = (last_cpu + 3) / 4 + 1;
 178         mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */
 179
 180         cpumask = malloc(mask_size);
 181         if (cpumask == NULL) {
 182                 pr_debug("failed to allocate cpu mask\n");
 183                 return -1;
 184         }
 185
 186         cpu_map__snprint_mask(cpumap, cpumask, mask_size);
 187
 188         ret = write_tracing_file("tracing_cpumask", cpumask);
 189
 190         free(cpumask);
 191         return ret;
 192 }
 193
 194 static int set_tracing_cpu(struct perf_ftrace *ftrace)
 195 {
 196         struct cpu_map *cpumap = ftrace->evlist->cpus;
 197
 198         if (!target__has_cpu(&ftrace->target))
 199                 return 0;
 200
 201         return set_tracing_cpumask(cpumap);
 202 }
 203
 204 static int reset_tracing_cpu(void)
 205 {
 206         struct cpu_map *cpumap = cpu_map__new(NULL);
 207         int ret;
 208
 209         ret = set_tracing_cpumask(cpumap);
 210         cpu_map__put(cpumap);
 211         return ret;
 212 }
 213
 214 static int __set_tracing_filter(const char *filter_file, struct list_head *funcs)
 215 {
 216         struct filter_entry *pos;
 217
 218         list_for_each_entry(pos, funcs, list) {
 219                 if (append_tracing_file(filter_file, pos->name) < 0)
 220                         return -1;
 221         }
 222
 223         return 0;
 224 }
 225
 226 static int set_tracing_filters(struct perf_ftrace *ftrace)
 227 {
 228         int ret;
 229
 230         ret = __set_tracing_filter("set_ftrace_filter", &ftrace->filters);
 231         if (ret < 0)
 232                 return ret;
 233
 234         ret = __set_tracing_filter("set_ftrace_notrace", &ftrace->notrace);
 235         if (ret < 0)
 236                 return ret;
 237
 238         ret = __set_tracing_filter("set_graph_function", &ftrace->graph_funcs);
 239         if (ret < 0)
 240                 return ret;
 241
 242         /* old kernels do not have this filter */
 243         __set_tracing_filter("set_graph_notrace", &ftrace->nograph_funcs);
 244
 245         return ret;
 246 }
 247
 248 static void reset_tracing_filters(void)
 249 {
 250         write_tracing_file("set_ftrace_filter", " ");
 251         write_tracing_file("set_ftrace_notrace", " ");
 252         write_tracing_file("set_graph_function", " ");
 253         write_tracing_file("set_graph_notrace", " ");
 254 }
 255
 256 static int set_tracing_depth(struct perf_ftrace *ftrace)
 257 {
 258         char buf[16];
 259
 260         if (ftrace->graph_depth == 0)
 261                 return 0;
 262
 263         if (ftrace->graph_depth < 0) {
 264                 pr_err("invalid graph depth: %d\n", ftrace->graph_depth);
 265                 return -1;
 266         }
 267
 268         snprintf(buf, sizeof(buf), "%d", ftrace->graph_depth);
 269
 270         if (write_tracing_file("max_graph_depth", buf) < 0)
 271                 return -1;
 272
 273         return 0;
 274 }
 275
 276 static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 277 {
 278         char *trace_file;
 279         int trace_fd;
 280         char buf[4096];
 281         struct pollfd pollfd = {
 282                 .events = POLLIN,
 283         };
 284
 285         if (geteuid() != 0) {
 286                 pr_err("ftrace only works for root!\n");
 287                 return -1;
 288         }
 289
 290         signal(SIGINT, sig_handler);
 291         signal(SIGUSR1, sig_handler);
 292         signal(SIGCHLD, sig_handler);
 293         signal(SIGPIPE, sig_handler);
 294
 295         if (reset_tracing_files(ftrace) < 0) {
 296                 pr_err("failed to reset ftrace\n");
 297                 goto out;
 298         }
 299
 300         /* reset ftrace buffer */
 301         if (write_tracing_file("trace", "0") < 0)
 302                 goto out;
 303
 304         if (argc && perf_evlist__prepare_workload(ftrace->evlist,
 305                                 &ftrace->target, argv, false,
 306                                 ftrace__workload_exec_failed_signal) < 0) {
 307                 goto out;
 308         }
 309
 310         if (set_tracing_pid(ftrace) < 0) {
 311                 pr_err("failed to set ftrace pid\n");
 312                 goto out_reset;
 313         }
 314
 315         if (set_tracing_cpu(ftrace) < 0) {
 316                 pr_err("failed to set tracing cpumask\n");
 317                 goto out_reset;
 318         }
 319
 320         if (set_tracing_filters(ftrace) < 0) {
 321                 pr_err("failed to set tracing filters\n");
 322                 goto out_reset;
 323         }
 324
 325         if (set_tracing_depth(ftrace) < 0) {
 326                 pr_err("failed to set graph depth\n");
 327                 goto out_reset;
 328         }
 329
 330         if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
 331                 pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
 332                 goto out_reset;
 333         }
 334
 335         setup_pager();
 336
 337         trace_file = get_tracing_file("trace_pipe");
 338         if (!trace_file) {
 339                 pr_err("failed to open trace_pipe\n");
 340                 goto out_reset;
 341         }
 342
 343         trace_fd = open(trace_file, O_RDONLY);
 344
 345         put_tracing_file(trace_file);
 346
 347         if (trace_fd < 0) {
 348                 pr_err("failed to open trace_pipe\n");
 349                 goto out_reset;
 350         }
 351
 352         fcntl(trace_fd, F_SETFL, O_NONBLOCK);
 353         pollfd.fd = trace_fd;
 354
 355         if (write_tracing_file("tracing_on", "1") < 0) {
 356                 pr_err("can't enable tracing\n");
 357                 goto out_close_fd;
 358         }
 359
 360         perf_evlist__start_workload(ftrace->evlist);
 361
 362         while (!done) {
 363                 if (poll(&pollfd, 1, -1) < 0)
 364                         break;
 365
 366                 if (pollfd.revents & POLLIN) {
 367                         int n = read(trace_fd, buf, sizeof(buf));
 368                         if (n < 0)
 369                                 break;
 370                         if (fwrite(buf, n, 1, stdout) != 1)
 371                                 break;
 372                 }
 373         }
 374
 375         write_tracing_file("tracing_on", "0");
 376
 377         /* read remaining buffer contents */
 378         while (true) {
 379                 int n = read(trace_fd, buf, sizeof(buf));
 380                 if (n <= 0)
 381                         break;
 382                 if (fwrite(buf, n, 1, stdout) != 1)
 383                         break;
 384         }
 385
 386 out_close_fd:
 387         close(trace_fd);
 388 out_reset:
 389         reset_tracing_files(ftrace);
 390 out:
 391         return done ? 0 : -1;
 392 }
 393
 394 static int perf_ftrace_config(const char *var, const char *value, void *cb)
 395 {
 396         struct perf_ftrace *ftrace = cb;
 397
 398         if (!strstarts(var, "ftrace."))
 399                 return 0;
 400
 401         if (strcmp(var, "ftrace.tracer"))
 402                 return -1;
 403
 404         if (!strcmp(value, "function_graph") ||
 405             !strcmp(value, "function")) {
 406                 ftrace->tracer = value;
 407                 return 0;
 408         }
 409
 410         pr_err("Please select \"function_graph\" (default) or \"function\"\n");
 411         return -1;
 412 }
 413
 414 static int parse_filter_func(const struct option *opt, const char *str,
 415                              int unset __maybe_unused)
 416 {
 417         struct list_head *head = opt->value;
 418         struct filter_entry *entry;
 419
 420         entry = malloc(sizeof(*entry) + strlen(str) + 1);
 421         if (entry == NULL)
 422                 return -ENOMEM;
 423
 424         strcpy(entry->name, str);
 425         list_add_tail(&entry->list, head);
 426
 427         return 0;
 428 }
 429
 430 static void delete_filter_func(struct list_head *head)
 431 {
 432         struct filter_entry *pos, *tmp;
 433
 434         list_for_each_entry_safe(pos, tmp, head, list) {
 435                 list_del(&pos->list);
 436                 free(pos);
 437         }
 438 }
 439
 440 int cmd_ftrace(int argc, const char **argv)
 441 {
 442         int ret;
 443         struct perf_ftrace ftrace = {
 444                 .tracer = DEFAULT_TRACER,
 445                 .target = { .uid = UINT_MAX, },
 446         };
 447         const char * const ftrace_usage[] = {
 448                 "perf ftrace [<options>] [<command>]",
 449                 "perf ftrace [<options>] -- <command> [<options>]",
 450                 NULL
 451         };
 452         const struct option ftrace_options[] = {
 453         OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
 454                    "tracer to use: function_graph(default) or function"),
 455         OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
 456                    "trace on existing process id"),
 457         OPT_INCR('v', "verbose", &verbose,
 458                  "be more verbose"),
 459         OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
 460                     "system-wide collection from all CPUs"),
 461         OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
 462                     "list of cpus to monitor"),
 463         OPT_CALLBACK('T', "trace-funcs", &ftrace.filters, "func",
 464                      "trace given functions only", parse_filter_func),
 465         OPT_CALLBACK('N', "notrace-funcs", &ftrace.notrace, "func",
 466                      "do not trace given functions", parse_filter_func),
 467         OPT_CALLBACK('G', "graph-funcs", &ftrace.graph_funcs, "func",
 468                      "Set graph filter on given functions", parse_filter_func),
 469         OPT_CALLBACK('g', "nograph-funcs", &ftrace.nograph_funcs, "func",
 470                      "Set nograph filter on given functions", parse_filter_func),
 471         OPT_INTEGER('D', "graph-depth", &ftrace.graph_depth,
 472                     "Max depth for function graph tracer"),
 473         OPT_END()
 474         };
 475
 476         INIT_LIST_HEAD(&ftrace.filters);
 477         INIT_LIST_HEAD(&ftrace.notrace);
 478         INIT_LIST_HEAD(&ftrace.graph_funcs);
 479         INIT_LIST_HEAD(&ftrace.nograph_funcs);
 480
 481         ret = perf_config(perf_ftrace_config, &ftrace);
 482         if (ret < 0)
 483                 return -1;
 484
 485         argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
 486                             PARSE_OPT_STOP_AT_NON_OPTION);
 487         if (!argc && target__none(&ftrace.target))
 488                 usage_with_options(ftrace_usage, ftrace_options);
 489
 490         ret = target__validate(&ftrace.target);
 491         if (ret) {
 492                 char errbuf[512];
 493
 494                 target__strerror(&ftrace.target, ret, errbuf, 512);
 495                 pr_err("%s\n", errbuf);
 496                 goto out_delete_filters;
 497         }
 498
 499         ftrace.evlist = perf_evlist__new();
 500         if (ftrace.evlist == NULL) {
 501                 ret = -ENOMEM;
 502                 goto out_delete_filters;
 503         }
 504
 505         ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);
 506         if (ret < 0)
 507                 goto out_delete_evlist;
 508
 509         ret = __cmd_ftrace(&ftrace, argc, argv);
 510
 511 out_delete_evlist:
 512         perf_evlist__delete(ftrace.evlist);
 513
 514 out_delete_filters:
 515         delete_filter_func(&ftrace.filters);
 516         delete_filter_func(&ftrace.notrace);
 517         delete_filter_func(&ftrace.graph_funcs);
 518         delete_filter_func(&ftrace.nograph_funcs);
 519
 520         return ret;
 521 }