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
sig_handler(int sig __maybe_unused)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 */
ftrace__workload_exec_failed_signal(int signo __maybe_unused,siginfo_t * info __maybe_unused,void * ucontext __maybe_unused)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
__write_tracing_file(const char * name,const char * val,bool append)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
write_tracing_file(const char * name,const char * val)106 static int write_tracing_file(const char *name, const char *val)
107 {
108 return __write_tracing_file(name, val, false);
109 }
110
append_tracing_file(const char * name,const char * val)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
reset_tracing_files(struct perf_ftrace * ftrace __maybe_unused)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
set_tracing_pid(struct perf_ftrace * ftrace)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
set_tracing_cpumask(struct cpu_map * cpumap)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 / 4 + 2; /* one more byte for EOS */
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
set_tracing_cpu(struct perf_ftrace * ftrace)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
reset_tracing_cpu(void)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
__set_tracing_filter(const char * filter_file,struct list_head * funcs)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
set_tracing_filters(struct perf_ftrace * ftrace)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
reset_tracing_filters(void)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
set_tracing_depth(struct perf_ftrace * ftrace)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
__cmd_ftrace(struct perf_ftrace * ftrace,int argc,const char ** argv)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
perf_ftrace_config(const char * var,const char * value,void * cb)380 static int perf_ftrace_config(const char *var, const char *value, void *cb)
381 {
382 struct perf_ftrace *ftrace = cb;
383
384 if (!strstarts(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
parse_filter_func(const struct option * opt,const char * str,int unset __maybe_unused)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
delete_filter_func(struct list_head * head)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
cmd_ftrace(int argc,const char ** argv)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 }
508