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