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1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (C) 2017, 2018, 2019, 2021 BMW Car IT GmbH | |
4 | * Author: Viktor Rosendahl (viktor.rosendahl@bmw.de) | |
5 | */ | |
6 | ||
7 | #define _GNU_SOURCE | |
8 | #define _POSIX_C_SOURCE 200809L | |
9 | ||
10 | #include <ctype.h> | |
11 | #include <stdbool.h> | |
12 | #include <stdio.h> | |
13 | #include <stdlib.h> | |
14 | #include <string.h> | |
15 | ||
16 | #include <err.h> | |
17 | #include <errno.h> | |
18 | #include <fcntl.h> | |
19 | #include <getopt.h> | |
20 | #include <sched.h> | |
21 | #include <linux/unistd.h> | |
22 | #include <signal.h> | |
23 | #include <sys/inotify.h> | |
24 | #include <unistd.h> | |
25 | #include <pthread.h> | |
26 | #include <tracefs.h> | |
27 | ||
28 | static const char *prg_name; | |
29 | static const char *prg_unknown = "unknown program name"; | |
30 | ||
31 | static int fd_stdout; | |
32 | ||
33 | static int sched_policy; | |
34 | static bool sched_policy_set; | |
35 | ||
36 | static int sched_pri; | |
37 | static bool sched_pri_set; | |
38 | ||
39 | static bool trace_enable = true; | |
40 | static bool setup_ftrace = true; | |
41 | static bool use_random_sleep; | |
42 | ||
43 | #define TRACE_OPTS \ | |
44 | C(FUNC_TR, "function-trace"), \ | |
45 | C(DISP_GR, "display-graph"), \ | |
46 | C(NR, NULL) | |
47 | ||
48 | #undef C | |
49 | #define C(a, b) OPTIDX_##a | |
50 | ||
51 | enum traceopt { | |
52 | TRACE_OPTS | |
53 | }; | |
54 | ||
55 | #undef C | |
56 | #define C(a, b) b | |
57 | ||
58 | static const char *const optstr[] = { | |
59 | TRACE_OPTS | |
60 | }; | |
61 | ||
62 | enum errhandling { | |
63 | ERR_EXIT = 0, | |
64 | ERR_WARN, | |
65 | ERR_CLEANUP, | |
66 | }; | |
67 | ||
68 | static bool use_options[OPTIDX_NR]; | |
69 | ||
70 | static char inotify_buffer[655360]; | |
71 | ||
72 | #define likely(x) __builtin_expect(!!(x), 1) | |
73 | #define unlikely(x) __builtin_expect(!!(x), 0) | |
74 | #define bool2str(x) (x ? "true":"false") | |
75 | ||
76 | #define DEFAULT_NR_PRINTER_THREADS (3) | |
77 | static unsigned int nr_threads = DEFAULT_NR_PRINTER_THREADS; | |
78 | ||
79 | #define DEFAULT_TABLE_SIZE (2) | |
80 | static unsigned int table_startsize = DEFAULT_TABLE_SIZE; | |
81 | ||
82 | static int verbosity; | |
83 | ||
84 | #define verbose_sizechange() (verbosity >= 1) | |
85 | #define verbose_lostevent() (verbosity >= 2) | |
86 | #define verbose_ftrace() (verbosity >= 1) | |
87 | ||
88 | #define was_changed(ORIG, CUR) (strcmp(ORIG, CUR) != 0) | |
89 | #define needs_change(CUR, WANTED) (strcmp(CUR, WANTED) != 0) | |
90 | ||
91 | static const char *debug_tracefile; | |
92 | static const char *debug_tracefile_dflt; | |
93 | static const char *debug_maxlat; | |
94 | static const char *debug_maxlat_dflt; | |
95 | static const char * const DEBUG_NOFILE = "[file not found]"; | |
96 | ||
97 | static const char * const TR_MAXLAT = "tracing_max_latency"; | |
98 | static const char * const TR_THRESH = "tracing_thresh"; | |
99 | static const char * const TR_CURRENT = "current_tracer"; | |
100 | static const char * const TR_OPTIONS = "trace_options"; | |
101 | ||
102 | static const char * const NOP_TRACER = "nop"; | |
103 | ||
104 | static const char * const OPT_NO_PREFIX = "no"; | |
105 | ||
106 | #define DFLT_THRESHOLD_US "0" | |
107 | static const char *threshold = DFLT_THRESHOLD_US; | |
108 | ||
109 | #define DEV_URANDOM "/dev/urandom" | |
110 | #define RT_DEFAULT_PRI (99) | |
111 | #define DEFAULT_PRI (0) | |
112 | ||
113 | #define USEC_PER_MSEC (1000L) | |
114 | #define NSEC_PER_USEC (1000L) | |
115 | #define NSEC_PER_MSEC (USEC_PER_MSEC * NSEC_PER_USEC) | |
116 | ||
117 | #define MSEC_PER_SEC (1000L) | |
118 | #define USEC_PER_SEC (USEC_PER_MSEC * MSEC_PER_SEC) | |
119 | #define NSEC_PER_SEC (NSEC_PER_MSEC * MSEC_PER_SEC) | |
120 | ||
121 | #define SLEEP_TIME_MS_DEFAULT (1000L) | |
122 | #define TRY_PRINTMUTEX_MS (1000) | |
123 | ||
124 | static long sleep_time = (USEC_PER_MSEC * SLEEP_TIME_MS_DEFAULT); | |
125 | ||
126 | static const char * const queue_full_warning = | |
127 | "Could not queue trace for printing. It is likely that events happen faster\n" | |
128 | "than what they can be printed. Probably partly because of random sleeping\n"; | |
129 | ||
130 | static const char * const no_tracer_msg = | |
131 | "Could not find any tracers! Running this program as root may help!\n"; | |
132 | ||
133 | static const char * const no_latency_tr_msg = | |
134 | "No latency tracers are supported by your kernel!\n"; | |
135 | ||
136 | struct policy { | |
137 | const char *name; | |
138 | int policy; | |
139 | int default_pri; | |
140 | }; | |
141 | ||
142 | static const struct policy policies[] = { | |
143 | { "other", SCHED_OTHER, DEFAULT_PRI }, | |
144 | { "batch", SCHED_BATCH, DEFAULT_PRI }, | |
145 | { "idle", SCHED_IDLE, DEFAULT_PRI }, | |
146 | { "rr", SCHED_RR, RT_DEFAULT_PRI }, | |
147 | { "fifo", SCHED_FIFO, RT_DEFAULT_PRI }, | |
148 | { NULL, 0, DEFAULT_PRI } | |
149 | }; | |
150 | ||
151 | /* | |
152 | * The default tracer will be the first on this list that is supported by the | |
153 | * currently running Linux kernel. | |
154 | */ | |
155 | static const char * const relevant_tracers[] = { | |
156 | "preemptirqsoff", | |
157 | "preemptoff", | |
158 | "irqsoff", | |
159 | "wakeup", | |
160 | "wakeup_rt", | |
161 | "wakeup_dl", | |
162 | NULL | |
163 | }; | |
164 | ||
165 | /* This is the list of tracers for which random sleep makes sense */ | |
166 | static const char * const random_tracers[] = { | |
167 | "preemptirqsoff", | |
168 | "preemptoff", | |
169 | "irqsoff", | |
170 | NULL | |
171 | }; | |
172 | ||
173 | static const char *current_tracer; | |
174 | static bool force_tracer; | |
175 | ||
176 | struct ftrace_state { | |
177 | char *tracer; | |
178 | char *thresh; | |
179 | bool opt[OPTIDX_NR]; | |
180 | bool opt_valid[OPTIDX_NR]; | |
181 | pthread_mutex_t mutex; | |
182 | }; | |
183 | ||
184 | struct entry { | |
185 | int ticket; | |
186 | int ticket_completed_ref; | |
187 | }; | |
188 | ||
189 | struct print_state { | |
190 | int ticket_counter; | |
191 | int ticket_completed; | |
192 | pthread_mutex_t mutex; | |
193 | pthread_cond_t cond; | |
194 | int cnt; | |
195 | pthread_mutex_t cnt_mutex; | |
196 | }; | |
197 | ||
198 | struct short_msg { | |
199 | char buf[160]; | |
200 | int len; | |
201 | }; | |
202 | ||
203 | static struct print_state printstate; | |
204 | static struct ftrace_state save_state; | |
205 | volatile sig_atomic_t signal_flag; | |
206 | ||
207 | #define PROB_TABLE_MAX_SIZE (1000) | |
208 | ||
209 | int probabilities[PROB_TABLE_MAX_SIZE]; | |
210 | ||
211 | struct sleep_table { | |
212 | int *table; | |
213 | int size; | |
214 | pthread_mutex_t mutex; | |
215 | }; | |
216 | ||
217 | static struct sleep_table sleeptable; | |
218 | ||
219 | #define QUEUE_SIZE (10) | |
220 | ||
221 | struct queue { | |
222 | struct entry entries[QUEUE_SIZE]; | |
223 | int next_prod_idx; | |
224 | int next_cons_idx; | |
225 | pthread_mutex_t mutex; | |
226 | pthread_cond_t cond; | |
227 | }; | |
228 | ||
229 | #define MAX_THREADS (40) | |
230 | ||
231 | struct queue printqueue; | |
232 | pthread_t printthread[MAX_THREADS]; | |
233 | pthread_mutex_t print_mtx; | |
234 | #define PRINT_BUFFER_SIZE (16 * 1024 * 1024) | |
235 | ||
236 | static void cleanup_exit(int status); | |
237 | static int set_trace_opt(const char *opt, bool value); | |
238 | ||
239 | static __always_inline void *malloc_or_die(size_t size) | |
240 | { | |
241 | void *ptr = malloc(size); | |
242 | ||
243 | if (unlikely(ptr == NULL)) { | |
244 | warn("malloc() failed"); | |
245 | cleanup_exit(EXIT_FAILURE); | |
246 | } | |
247 | return ptr; | |
248 | } | |
249 | ||
250 | static __always_inline void *malloc_or_die_nocleanup(size_t size) | |
251 | { | |
252 | void *ptr = malloc(size); | |
253 | ||
254 | if (unlikely(ptr == NULL)) | |
255 | err(0, "malloc() failed"); | |
256 | return ptr; | |
257 | } | |
258 | ||
259 | static __always_inline void write_or_die(int fd, const char *buf, size_t count) | |
260 | { | |
261 | ssize_t r; | |
262 | ||
263 | do { | |
264 | r = write(fd, buf, count); | |
265 | if (unlikely(r < 0)) { | |
266 | if (errno == EINTR) | |
267 | continue; | |
268 | warn("write() failed"); | |
269 | cleanup_exit(EXIT_FAILURE); | |
270 | } | |
271 | count -= r; | |
272 | buf += r; | |
273 | } while (count > 0); | |
274 | } | |
275 | ||
276 | static __always_inline void clock_gettime_or_die(clockid_t clk_id, | |
277 | struct timespec *tp) | |
278 | { | |
279 | int r = clock_gettime(clk_id, tp); | |
280 | ||
281 | if (unlikely(r != 0)) | |
282 | err(EXIT_FAILURE, "clock_gettime() failed"); | |
283 | } | |
284 | ||
285 | static __always_inline void sigemptyset_or_die(sigset_t *s) | |
286 | { | |
287 | if (unlikely(sigemptyset(s) != 0)) { | |
288 | warn("sigemptyset() failed"); | |
289 | cleanup_exit(EXIT_FAILURE); | |
290 | } | |
291 | } | |
292 | ||
293 | static __always_inline void sigaddset_or_die(sigset_t *s, int signum) | |
294 | { | |
295 | if (unlikely(sigaddset(s, signum) != 0)) { | |
296 | warn("sigemptyset() failed"); | |
297 | cleanup_exit(EXIT_FAILURE); | |
298 | } | |
299 | } | |
300 | ||
301 | static __always_inline void sigaction_or_die(int signum, | |
302 | const struct sigaction *act, | |
303 | struct sigaction *oldact) | |
304 | { | |
305 | if (unlikely(sigaction(signum, act, oldact) != 0)) { | |
306 | warn("sigaction() failed"); | |
307 | cleanup_exit(EXIT_FAILURE); | |
308 | } | |
309 | } | |
310 | ||
311 | static void open_stdout(void) | |
312 | { | |
313 | if (setvbuf(stdout, NULL, _IONBF, 0) != 0) | |
314 | err(EXIT_FAILURE, "setvbuf() failed"); | |
315 | fd_stdout = fileno(stdout); | |
316 | if (fd_stdout < 0) | |
317 | err(EXIT_FAILURE, "fileno() failed"); | |
318 | } | |
319 | ||
320 | /* | |
321 | * It's not worth it to call cleanup_exit() from mutex functions because | |
322 | * cleanup_exit() uses mutexes. | |
323 | */ | |
324 | static __always_inline void mutex_lock(pthread_mutex_t *mtx) | |
325 | { | |
326 | errno = pthread_mutex_lock(mtx); | |
327 | if (unlikely(errno)) | |
328 | err(EXIT_FAILURE, "pthread_mutex_lock() failed"); | |
329 | } | |
330 | ||
331 | ||
332 | static __always_inline void mutex_unlock(pthread_mutex_t *mtx) | |
333 | { | |
334 | errno = pthread_mutex_unlock(mtx); | |
335 | if (unlikely(errno)) | |
336 | err(EXIT_FAILURE, "pthread_mutex_unlock() failed"); | |
337 | } | |
338 | ||
339 | static __always_inline void cond_signal(pthread_cond_t *cond) | |
340 | { | |
341 | errno = pthread_cond_signal(cond); | |
342 | if (unlikely(errno)) | |
343 | err(EXIT_FAILURE, "pthread_cond_signal() failed"); | |
344 | } | |
345 | ||
346 | static __always_inline void cond_wait(pthread_cond_t *restrict cond, | |
347 | pthread_mutex_t *restrict mutex) | |
348 | { | |
349 | errno = pthread_cond_wait(cond, mutex); | |
350 | if (unlikely(errno)) | |
351 | err(EXIT_FAILURE, "pthread_cond_wait() failed"); | |
352 | } | |
353 | ||
354 | static __always_inline void cond_broadcast(pthread_cond_t *cond) | |
355 | { | |
356 | errno = pthread_cond_broadcast(cond); | |
357 | if (unlikely(errno)) | |
358 | err(EXIT_FAILURE, "pthread_cond_broadcast() failed"); | |
359 | } | |
360 | ||
361 | static __always_inline void | |
362 | mutex_init(pthread_mutex_t *mutex, | |
363 | const pthread_mutexattr_t *attr) | |
364 | { | |
365 | errno = pthread_mutex_init(mutex, attr); | |
366 | if (errno) | |
367 | err(EXIT_FAILURE, "pthread_mutex_init() failed"); | |
368 | } | |
369 | ||
370 | static __always_inline void mutexattr_init(pthread_mutexattr_t *attr) | |
371 | { | |
372 | errno = pthread_mutexattr_init(attr); | |
373 | if (errno) | |
374 | err(EXIT_FAILURE, "pthread_mutexattr_init() failed"); | |
375 | } | |
376 | ||
377 | static __always_inline void mutexattr_destroy(pthread_mutexattr_t *attr) | |
378 | { | |
379 | errno = pthread_mutexattr_destroy(attr); | |
380 | if (errno) | |
381 | err(EXIT_FAILURE, "pthread_mutexattr_destroy() failed"); | |
382 | } | |
383 | ||
384 | static __always_inline void mutexattr_settype(pthread_mutexattr_t *attr, | |
385 | int type) | |
386 | { | |
387 | errno = pthread_mutexattr_settype(attr, type); | |
388 | if (errno) | |
389 | err(EXIT_FAILURE, "pthread_mutexattr_settype() failed"); | |
390 | } | |
391 | ||
392 | static __always_inline void condattr_init(pthread_condattr_t *attr) | |
393 | { | |
394 | errno = pthread_condattr_init(attr); | |
395 | if (errno) | |
396 | err(EXIT_FAILURE, "pthread_condattr_init() failed"); | |
397 | } | |
398 | ||
399 | static __always_inline void condattr_destroy(pthread_condattr_t *attr) | |
400 | { | |
401 | errno = pthread_condattr_destroy(attr); | |
402 | if (errno) | |
403 | err(EXIT_FAILURE, "pthread_condattr_destroy() failed"); | |
404 | } | |
405 | ||
406 | static __always_inline void condattr_setclock(pthread_condattr_t *attr, | |
407 | clockid_t clock_id) | |
408 | { | |
409 | errno = pthread_condattr_setclock(attr, clock_id); | |
410 | if (unlikely(errno)) | |
411 | err(EXIT_FAILURE, "pthread_condattr_setclock() failed"); | |
412 | } | |
413 | ||
414 | static __always_inline void cond_init(pthread_cond_t *cond, | |
415 | const pthread_condattr_t *attr) | |
416 | { | |
417 | errno = pthread_cond_init(cond, attr); | |
418 | if (errno) | |
419 | err(EXIT_FAILURE, "pthread_cond_init() failed"); | |
420 | } | |
421 | ||
422 | static __always_inline int | |
423 | cond_timedwait(pthread_cond_t *restrict cond, | |
424 | pthread_mutex_t *restrict mutex, | |
425 | const struct timespec *restrict abstime) | |
426 | { | |
427 | errno = pthread_cond_timedwait(cond, mutex, abstime); | |
428 | if (errno && errno != ETIMEDOUT) | |
429 | err(EXIT_FAILURE, "pthread_cond_timedwait() failed"); | |
430 | return errno; | |
431 | } | |
432 | ||
433 | static void init_printstate(void) | |
434 | { | |
435 | pthread_condattr_t cattr; | |
436 | ||
437 | printstate.ticket_counter = 0; | |
438 | printstate.ticket_completed = 0; | |
439 | printstate.cnt = 0; | |
440 | ||
441 | mutex_init(&printstate.mutex, NULL); | |
442 | ||
443 | condattr_init(&cattr); | |
444 | condattr_setclock(&cattr, CLOCK_MONOTONIC); | |
445 | cond_init(&printstate.cond, &cattr); | |
446 | condattr_destroy(&cattr); | |
447 | } | |
448 | ||
449 | static void init_print_mtx(void) | |
450 | { | |
451 | pthread_mutexattr_t mattr; | |
452 | ||
453 | mutexattr_init(&mattr); | |
454 | mutexattr_settype(&mattr, PTHREAD_MUTEX_RECURSIVE); | |
455 | mutex_init(&print_mtx, &mattr); | |
456 | mutexattr_destroy(&mattr); | |
457 | ||
458 | } | |
459 | ||
460 | static void signal_blocking(int how) | |
461 | { | |
462 | sigset_t s; | |
463 | ||
464 | sigemptyset_or_die(&s); | |
465 | sigaddset_or_die(&s, SIGHUP); | |
466 | sigaddset_or_die(&s, SIGTERM); | |
467 | sigaddset_or_die(&s, SIGINT); | |
468 | ||
469 | errno = pthread_sigmask(how, &s, NULL); | |
470 | if (unlikely(errno)) { | |
471 | warn("pthread_sigmask() failed"); | |
472 | cleanup_exit(EXIT_FAILURE); | |
473 | } | |
474 | } | |
475 | ||
476 | static void signal_handler(int num) | |
477 | { | |
478 | signal_flag = num; | |
479 | } | |
480 | ||
481 | static void setup_sig_handler(void) | |
482 | { | |
483 | struct sigaction sa; | |
484 | ||
485 | memset(&sa, 0, sizeof(sa)); | |
486 | sa.sa_handler = signal_handler; | |
487 | ||
488 | sigaction_or_die(SIGHUP, &sa, NULL); | |
489 | sigaction_or_die(SIGTERM, &sa, NULL); | |
490 | sigaction_or_die(SIGINT, &sa, NULL); | |
491 | } | |
492 | ||
493 | static void process_signal(int signal) | |
494 | { | |
495 | char *name; | |
496 | ||
497 | name = strsignal(signal); | |
498 | if (name == NULL) | |
499 | printf("Received signal %d\n", signal); | |
500 | else | |
501 | printf("Received signal %d (%s)\n", signal, name); | |
502 | cleanup_exit(EXIT_SUCCESS); | |
503 | } | |
504 | ||
505 | static __always_inline void check_signals(void) | |
506 | { | |
507 | int signal = signal_flag; | |
508 | ||
509 | if (unlikely(signal)) | |
510 | process_signal(signal); | |
511 | } | |
512 | ||
513 | static __always_inline void get_time_in_future(struct timespec *future, | |
514 | long time_us) | |
515 | { | |
516 | long nsec; | |
517 | ||
518 | clock_gettime_or_die(CLOCK_MONOTONIC, future); | |
519 | future->tv_sec += time_us / USEC_PER_SEC; | |
520 | nsec = future->tv_nsec + (time_us * NSEC_PER_USEC) % NSEC_PER_SEC; | |
521 | if (nsec >= NSEC_PER_SEC) { | |
522 | future->tv_nsec = nsec % NSEC_PER_SEC; | |
523 | future->tv_sec += 1; | |
524 | } | |
525 | } | |
526 | ||
527 | static __always_inline bool time_has_passed(const struct timespec *time) | |
528 | { | |
529 | struct timespec now; | |
530 | ||
531 | clock_gettime_or_die(CLOCK_MONOTONIC, &now); | |
532 | if (now.tv_sec > time->tv_sec) | |
533 | return true; | |
534 | if (now.tv_sec < time->tv_sec) | |
535 | return false; | |
536 | return (now.tv_nsec >= time->tv_nsec); | |
537 | } | |
538 | ||
539 | static bool mutex_trylock_limit(pthread_mutex_t *mutex, int time_ms) | |
540 | { | |
541 | long time_us = time_ms * USEC_PER_MSEC; | |
542 | struct timespec limit; | |
543 | ||
544 | get_time_in_future(&limit, time_us); | |
545 | do { | |
546 | errno = pthread_mutex_trylock(mutex); | |
547 | if (errno && errno != EBUSY) | |
548 | err(EXIT_FAILURE, "pthread_mutex_trylock() failed"); | |
549 | } while (errno && !time_has_passed(&limit)); | |
550 | return errno == 0; | |
551 | } | |
552 | ||
553 | static void restore_trace_opts(const struct ftrace_state *state, | |
554 | const bool *cur) | |
555 | { | |
556 | int i; | |
557 | int r; | |
558 | ||
559 | for (i = 0; i < OPTIDX_NR; i++) | |
560 | if (state->opt_valid[i] && state->opt[i] != cur[i]) { | |
561 | r = set_trace_opt(optstr[i], state->opt[i]); | |
562 | if (r < 0) | |
563 | warnx("Failed to restore the %s option to %s", | |
564 | optstr[i], bool2str(state->opt[i])); | |
565 | else if (verbose_ftrace()) | |
566 | printf("Restored the %s option in %s to %s\n", | |
567 | optstr[i], TR_OPTIONS, | |
568 | bool2str(state->opt[i])); | |
569 | } | |
570 | } | |
571 | ||
572 | static char *read_file(const char *file, enum errhandling h) | |
573 | { | |
574 | int psize; | |
575 | char *r; | |
576 | static const char *emsg = "Failed to read the %s file"; | |
577 | ||
578 | r = tracefs_instance_file_read(NULL, file, &psize); | |
579 | if (!r) { | |
580 | if (h) { | |
581 | warn(emsg, file); | |
582 | if (h == ERR_CLEANUP) | |
583 | cleanup_exit(EXIT_FAILURE); | |
584 | } else | |
585 | errx(EXIT_FAILURE, emsg, file); | |
586 | } | |
587 | ||
588 | if (r && r[psize - 1] == '\n') | |
589 | r[psize - 1] = '\0'; | |
590 | return r; | |
591 | } | |
592 | ||
593 | static void restore_file(const char *file, char **saved, const char *cur) | |
594 | { | |
595 | if (*saved && was_changed(*saved, cur)) { | |
596 | if (tracefs_instance_file_write(NULL, file, *saved) < 0) | |
597 | warnx("Failed to restore %s to %s!", file, *saved); | |
598 | else if (verbose_ftrace()) | |
599 | printf("Restored %s to %s\n", file, *saved); | |
600 | free(*saved); | |
601 | *saved = NULL; | |
602 | } | |
603 | } | |
604 | ||
605 | static void restore_ftrace(void) | |
606 | { | |
607 | mutex_lock(&save_state.mutex); | |
608 | ||
609 | restore_file(TR_CURRENT, &save_state.tracer, current_tracer); | |
610 | restore_file(TR_THRESH, &save_state.thresh, threshold); | |
611 | restore_trace_opts(&save_state, use_options); | |
612 | ||
613 | mutex_unlock(&save_state.mutex); | |
614 | } | |
615 | ||
616 | static void cleanup_exit(int status) | |
617 | { | |
618 | char *maxlat; | |
619 | ||
620 | if (!setup_ftrace) | |
621 | exit(status); | |
622 | ||
623 | /* | |
624 | * We try the print_mtx for 1 sec in order to avoid garbled | |
625 | * output if possible, but if it cannot be obtained we proceed anyway. | |
626 | */ | |
627 | mutex_trylock_limit(&print_mtx, TRY_PRINTMUTEX_MS); | |
628 | ||
629 | maxlat = read_file(TR_MAXLAT, ERR_WARN); | |
630 | if (maxlat) { | |
631 | printf("The maximum detected latency was: %sus\n", maxlat); | |
632 | free(maxlat); | |
633 | } | |
634 | ||
635 | restore_ftrace(); | |
636 | /* | |
637 | * We do not need to unlock the print_mtx here because we will exit at | |
638 | * the end of this function. Unlocking print_mtx causes problems if a | |
639 | * print thread happens to be waiting for the mutex because we have | |
640 | * just changed the ftrace settings to the original and thus the | |
641 | * print thread would output incorrect data from ftrace. | |
642 | */ | |
643 | exit(status); | |
644 | } | |
645 | ||
646 | static void init_save_state(void) | |
647 | { | |
648 | pthread_mutexattr_t mattr; | |
649 | ||
650 | mutexattr_init(&mattr); | |
651 | mutexattr_settype(&mattr, PTHREAD_MUTEX_RECURSIVE); | |
652 | mutex_init(&save_state.mutex, &mattr); | |
653 | mutexattr_destroy(&mattr); | |
654 | ||
655 | save_state.tracer = NULL; | |
656 | save_state.thresh = NULL; | |
657 | save_state.opt_valid[OPTIDX_FUNC_TR] = false; | |
658 | save_state.opt_valid[OPTIDX_DISP_GR] = false; | |
659 | } | |
660 | ||
661 | static int printstate_next_ticket(struct entry *req) | |
662 | { | |
663 | int r; | |
664 | ||
665 | r = ++(printstate.ticket_counter); | |
666 | req->ticket = r; | |
667 | req->ticket_completed_ref = printstate.ticket_completed; | |
668 | cond_broadcast(&printstate.cond); | |
669 | return r; | |
670 | } | |
671 | ||
672 | static __always_inline | |
673 | void printstate_mark_req_completed(const struct entry *req) | |
674 | { | |
675 | if (req->ticket > printstate.ticket_completed) | |
676 | printstate.ticket_completed = req->ticket; | |
677 | } | |
678 | ||
679 | static __always_inline | |
680 | bool printstate_has_new_req_arrived(const struct entry *req) | |
681 | { | |
682 | return (printstate.ticket_counter != req->ticket); | |
683 | } | |
684 | ||
685 | static __always_inline int printstate_cnt_inc(void) | |
686 | { | |
687 | int value; | |
688 | ||
689 | mutex_lock(&printstate.cnt_mutex); | |
690 | value = ++printstate.cnt; | |
691 | mutex_unlock(&printstate.cnt_mutex); | |
692 | return value; | |
693 | } | |
694 | ||
695 | static __always_inline int printstate_cnt_dec(void) | |
696 | { | |
697 | int value; | |
698 | ||
699 | mutex_lock(&printstate.cnt_mutex); | |
700 | value = --printstate.cnt; | |
701 | mutex_unlock(&printstate.cnt_mutex); | |
702 | return value; | |
703 | } | |
704 | ||
705 | static __always_inline int printstate_cnt_read(void) | |
706 | { | |
707 | int value; | |
708 | ||
709 | mutex_lock(&printstate.cnt_mutex); | |
710 | value = printstate.cnt; | |
711 | mutex_unlock(&printstate.cnt_mutex); | |
712 | return value; | |
713 | } | |
714 | ||
715 | static __always_inline | |
716 | bool prev_req_won_race(const struct entry *req) | |
717 | { | |
718 | return (printstate.ticket_completed != req->ticket_completed_ref); | |
719 | } | |
720 | ||
721 | static void sleeptable_resize(int size, bool printout, struct short_msg *msg) | |
722 | { | |
723 | int bytes; | |
724 | ||
725 | if (printout) { | |
726 | msg->len = 0; | |
727 | if (unlikely(size > PROB_TABLE_MAX_SIZE)) | |
728 | bytes = snprintf(msg->buf, sizeof(msg->buf), | |
729 | "Cannot increase probability table to %d (maximum size reached)\n", size); | |
730 | else | |
731 | bytes = snprintf(msg->buf, sizeof(msg->buf), | |
732 | "Increasing probability table to %d\n", size); | |
733 | if (bytes < 0) | |
734 | warn("snprintf() failed"); | |
735 | else | |
736 | msg->len = bytes; | |
737 | } | |
738 | ||
739 | if (unlikely(size < 0)) { | |
740 | /* Should never happen */ | |
741 | warnx("Bad program state at %s:%d", __FILE__, __LINE__); | |
742 | cleanup_exit(EXIT_FAILURE); | |
743 | return; | |
744 | } | |
745 | sleeptable.size = size; | |
746 | sleeptable.table = &probabilities[PROB_TABLE_MAX_SIZE - size]; | |
747 | } | |
748 | ||
749 | static void init_probabilities(void) | |
750 | { | |
751 | int i; | |
752 | int j = 1000; | |
753 | ||
754 | for (i = 0; i < PROB_TABLE_MAX_SIZE; i++) { | |
755 | probabilities[i] = 1000 / j; | |
756 | j--; | |
757 | } | |
758 | mutex_init(&sleeptable.mutex, NULL); | |
759 | } | |
760 | ||
761 | static int table_get_probability(const struct entry *req, | |
762 | struct short_msg *msg) | |
763 | { | |
764 | int diff = req->ticket - req->ticket_completed_ref; | |
765 | int rval = 0; | |
766 | ||
767 | msg->len = 0; | |
768 | diff--; | |
769 | /* Should never happen...*/ | |
770 | if (unlikely(diff < 0)) { | |
771 | warnx("Programmer assumption error at %s:%d\n", __FILE__, | |
772 | __LINE__); | |
773 | cleanup_exit(EXIT_FAILURE); | |
774 | } | |
775 | mutex_lock(&sleeptable.mutex); | |
776 | if (diff >= (sleeptable.size - 1)) { | |
777 | rval = sleeptable.table[sleeptable.size - 1]; | |
778 | sleeptable_resize(sleeptable.size + 1, verbose_sizechange(), | |
779 | msg); | |
780 | } else { | |
781 | rval = sleeptable.table[diff]; | |
782 | } | |
783 | mutex_unlock(&sleeptable.mutex); | |
784 | return rval; | |
785 | } | |
786 | ||
787 | static void init_queue(struct queue *q) | |
788 | { | |
789 | q->next_prod_idx = 0; | |
790 | q->next_cons_idx = 0; | |
791 | mutex_init(&q->mutex, NULL); | |
792 | errno = pthread_cond_init(&q->cond, NULL); | |
793 | if (errno) | |
794 | err(EXIT_FAILURE, "pthread_cond_init() failed"); | |
795 | } | |
796 | ||
797 | static __always_inline int queue_len(const struct queue *q) | |
798 | { | |
799 | if (q->next_prod_idx >= q->next_cons_idx) | |
800 | return q->next_prod_idx - q->next_cons_idx; | |
801 | else | |
802 | return QUEUE_SIZE - q->next_cons_idx + q->next_prod_idx; | |
803 | } | |
804 | ||
805 | static __always_inline int queue_nr_free(const struct queue *q) | |
806 | { | |
807 | int nr_free = QUEUE_SIZE - queue_len(q); | |
808 | ||
809 | /* | |
810 | * If there is only one slot left we will anyway lie and claim that the | |
811 | * queue is full because adding an element will make it appear empty | |
812 | */ | |
813 | if (nr_free == 1) | |
814 | nr_free = 0; | |
815 | return nr_free; | |
816 | } | |
817 | ||
818 | static __always_inline void queue_idx_inc(int *idx) | |
819 | { | |
820 | *idx = (*idx + 1) % QUEUE_SIZE; | |
821 | } | |
822 | ||
823 | static __always_inline void queue_push_to_back(struct queue *q, | |
824 | const struct entry *e) | |
825 | { | |
826 | q->entries[q->next_prod_idx] = *e; | |
827 | queue_idx_inc(&q->next_prod_idx); | |
828 | } | |
829 | ||
830 | static __always_inline struct entry queue_pop_from_front(struct queue *q) | |
831 | { | |
832 | struct entry e = q->entries[q->next_cons_idx]; | |
833 | ||
834 | queue_idx_inc(&q->next_cons_idx); | |
835 | return e; | |
836 | } | |
837 | ||
838 | static __always_inline void queue_cond_signal(struct queue *q) | |
839 | { | |
840 | cond_signal(&q->cond); | |
841 | } | |
842 | ||
843 | static __always_inline void queue_cond_wait(struct queue *q) | |
844 | { | |
845 | cond_wait(&q->cond, &q->mutex); | |
846 | } | |
847 | ||
848 | static __always_inline int queue_try_to_add_entry(struct queue *q, | |
849 | const struct entry *e) | |
850 | { | |
851 | int r = 0; | |
852 | ||
853 | mutex_lock(&q->mutex); | |
854 | if (queue_nr_free(q) > 0) { | |
855 | queue_push_to_back(q, e); | |
856 | cond_signal(&q->cond); | |
857 | } else | |
858 | r = -1; | |
859 | mutex_unlock(&q->mutex); | |
860 | return r; | |
861 | } | |
862 | ||
863 | static struct entry queue_wait_for_entry(struct queue *q) | |
864 | { | |
865 | struct entry e; | |
866 | ||
867 | mutex_lock(&q->mutex); | |
868 | while (true) { | |
869 | if (queue_len(&printqueue) > 0) { | |
870 | e = queue_pop_from_front(q); | |
871 | break; | |
872 | } | |
873 | queue_cond_wait(q); | |
874 | } | |
875 | mutex_unlock(&q->mutex); | |
876 | ||
877 | return e; | |
878 | } | |
879 | ||
880 | static const struct policy *policy_from_name(const char *name) | |
881 | { | |
882 | const struct policy *p = &policies[0]; | |
883 | ||
884 | while (p->name != NULL) { | |
885 | if (!strcmp(name, p->name)) | |
886 | return p; | |
887 | p++; | |
888 | } | |
889 | return NULL; | |
890 | } | |
891 | ||
892 | static const char *policy_name(int policy) | |
893 | { | |
894 | const struct policy *p = &policies[0]; | |
895 | static const char *rval = "unknown"; | |
896 | ||
897 | while (p->name != NULL) { | |
898 | if (p->policy == policy) | |
899 | return p->name; | |
900 | p++; | |
901 | } | |
902 | return rval; | |
903 | } | |
904 | ||
905 | static bool is_relevant_tracer(const char *name) | |
906 | { | |
907 | unsigned int i; | |
908 | ||
909 | for (i = 0; relevant_tracers[i]; i++) | |
910 | if (!strcmp(name, relevant_tracers[i])) | |
911 | return true; | |
912 | return false; | |
913 | } | |
914 | ||
915 | static bool random_makes_sense(const char *name) | |
916 | { | |
917 | unsigned int i; | |
918 | ||
919 | for (i = 0; random_tracers[i]; i++) | |
920 | if (!strcmp(name, random_tracers[i])) | |
921 | return true; | |
922 | return false; | |
923 | } | |
924 | ||
925 | static void show_available(void) | |
926 | { | |
927 | char **tracers; | |
928 | int found = 0; | |
929 | int i; | |
930 | ||
931 | tracers = tracefs_tracers(NULL); | |
932 | for (i = 0; tracers && tracers[i]; i++) { | |
933 | if (is_relevant_tracer(tracers[i])) | |
934 | found++; | |
935 | } | |
936 | ||
937 | if (!tracers) { | |
df73757c | 938 | warnx("%s", no_tracer_msg); |
e23db805 VR |
939 | return; |
940 | } | |
941 | ||
942 | if (!found) { | |
df73757c | 943 | warnx("%s", no_latency_tr_msg); |
e23db805 VR |
944 | tracefs_list_free(tracers); |
945 | return; | |
946 | } | |
947 | ||
948 | printf("The following latency tracers are available on your system:\n"); | |
949 | for (i = 0; tracers[i]; i++) { | |
950 | if (is_relevant_tracer(tracers[i])) | |
951 | printf("%s\n", tracers[i]); | |
952 | } | |
953 | tracefs_list_free(tracers); | |
954 | } | |
955 | ||
956 | static bool tracer_valid(const char *name, bool *notracer) | |
957 | { | |
958 | char **tracers; | |
959 | int i; | |
960 | bool rval = false; | |
961 | ||
962 | *notracer = false; | |
963 | tracers = tracefs_tracers(NULL); | |
964 | if (!tracers) { | |
965 | *notracer = true; | |
966 | return false; | |
967 | } | |
968 | for (i = 0; tracers[i]; i++) | |
969 | if (!strcmp(tracers[i], name)) { | |
970 | rval = true; | |
971 | break; | |
972 | } | |
973 | tracefs_list_free(tracers); | |
974 | return rval; | |
975 | } | |
976 | ||
977 | static const char *find_default_tracer(void) | |
978 | { | |
979 | int i; | |
980 | bool notracer; | |
981 | bool valid; | |
982 | ||
983 | for (i = 0; relevant_tracers[i]; i++) { | |
984 | valid = tracer_valid(relevant_tracers[i], ¬racer); | |
985 | if (notracer) | |
df73757c | 986 | errx(EXIT_FAILURE, "%s", no_tracer_msg); |
e23db805 VR |
987 | if (valid) |
988 | return relevant_tracers[i]; | |
989 | } | |
990 | return NULL; | |
991 | } | |
992 | ||
993 | static bool toss_coin(struct drand48_data *buffer, unsigned int prob) | |
994 | { | |
995 | long r; | |
996 | ||
997 | if (unlikely(lrand48_r(buffer, &r))) { | |
998 | warnx("lrand48_r() failed"); | |
999 | cleanup_exit(EXIT_FAILURE); | |
1000 | } | |
1001 | r = r % 1000L; | |
1002 | if (r < prob) | |
1003 | return true; | |
1004 | else | |
1005 | return false; | |
1006 | } | |
1007 | ||
1008 | ||
1009 | static long go_to_sleep(const struct entry *req) | |
1010 | { | |
1011 | struct timespec future; | |
1012 | long delay = sleep_time; | |
1013 | ||
1014 | get_time_in_future(&future, delay); | |
1015 | ||
1016 | mutex_lock(&printstate.mutex); | |
1017 | while (!printstate_has_new_req_arrived(req)) { | |
1018 | cond_timedwait(&printstate.cond, &printstate.mutex, &future); | |
1019 | if (time_has_passed(&future)) | |
1020 | break; | |
421d9d1b | 1021 | } |
e23db805 VR |
1022 | |
1023 | if (printstate_has_new_req_arrived(req)) | |
1024 | delay = -1; | |
1025 | mutex_unlock(&printstate.mutex); | |
1026 | ||
1027 | return delay; | |
1028 | } | |
1029 | ||
1030 | ||
1031 | static void set_priority(void) | |
1032 | { | |
1033 | int r; | |
1034 | pid_t pid; | |
1035 | struct sched_param param; | |
1036 | ||
1037 | memset(¶m, 0, sizeof(param)); | |
1038 | param.sched_priority = sched_pri; | |
1039 | ||
1040 | pid = getpid(); | |
1041 | r = sched_setscheduler(pid, sched_policy, ¶m); | |
1042 | ||
1043 | if (r != 0) | |
1044 | err(EXIT_FAILURE, "sched_setscheduler() failed"); | |
1045 | } | |
1046 | ||
1047 | pid_t latency_collector_gettid(void) | |
1048 | { | |
1049 | return (pid_t) syscall(__NR_gettid); | |
1050 | } | |
1051 | ||
1052 | static void print_priority(void) | |
1053 | { | |
1054 | pid_t tid; | |
1055 | int policy; | |
1056 | int r; | |
1057 | struct sched_param param; | |
1058 | ||
1059 | tid = latency_collector_gettid(); | |
1060 | r = pthread_getschedparam(pthread_self(), &policy, ¶m); | |
1061 | if (r != 0) { | |
1062 | warn("pthread_getschedparam() failed"); | |
1063 | cleanup_exit(EXIT_FAILURE); | |
1064 | } | |
1065 | mutex_lock(&print_mtx); | |
1066 | printf("Thread %d runs with scheduling policy %s and priority %d\n", | |
1067 | tid, policy_name(policy), param.sched_priority); | |
1068 | mutex_unlock(&print_mtx); | |
1069 | } | |
1070 | ||
1071 | static __always_inline | |
1072 | void __print_skipmessage(const struct short_msg *resize_msg, | |
1073 | const struct timespec *timestamp, char *buffer, | |
1074 | size_t bufspace, const struct entry *req, bool excuse, | |
1075 | const char *str) | |
1076 | { | |
1077 | ssize_t bytes = 0; | |
1078 | char *p = &buffer[0]; | |
1079 | long us, sec; | |
1080 | int r; | |
1081 | ||
1082 | sec = timestamp->tv_sec; | |
1083 | us = timestamp->tv_nsec / 1000; | |
1084 | ||
1085 | if (resize_msg != NULL && resize_msg->len > 0) { | |
1086 | strncpy(p, resize_msg->buf, resize_msg->len); | |
1087 | bytes += resize_msg->len; | |
1088 | p += resize_msg->len; | |
1089 | bufspace -= resize_msg->len; | |
1090 | } | |
1091 | ||
1092 | if (excuse) | |
1093 | r = snprintf(p, bufspace, | |
1094 | "%ld.%06ld Latency %d printout skipped due to %s\n", | |
1095 | sec, us, req->ticket, str); | |
1096 | else | |
1097 | r = snprintf(p, bufspace, "%ld.%06ld Latency %d detected\n", | |
1098 | sec, us, req->ticket); | |
1099 | ||
1100 | if (r < 0) | |
1101 | warn("snprintf() failed"); | |
1102 | else | |
1103 | bytes += r; | |
1104 | ||
1105 | /* These prints could happen concurrently */ | |
1106 | mutex_lock(&print_mtx); | |
1107 | write_or_die(fd_stdout, buffer, bytes); | |
1108 | mutex_unlock(&print_mtx); | |
1109 | } | |
1110 | ||
1111 | static void print_skipmessage(const struct short_msg *resize_msg, | |
1112 | const struct timespec *timestamp, char *buffer, | |
1113 | size_t bufspace, const struct entry *req, | |
1114 | bool excuse) | |
1115 | { | |
1116 | __print_skipmessage(resize_msg, timestamp, buffer, bufspace, req, | |
1117 | excuse, "random delay"); | |
1118 | } | |
1119 | ||
1120 | static void print_lostmessage(const struct timespec *timestamp, char *buffer, | |
1121 | size_t bufspace, const struct entry *req, | |
1122 | const char *reason) | |
1123 | { | |
1124 | __print_skipmessage(NULL, timestamp, buffer, bufspace, req, true, | |
1125 | reason); | |
1126 | } | |
1127 | ||
1128 | static void print_tracefile(const struct short_msg *resize_msg, | |
1129 | const struct timespec *timestamp, char *buffer, | |
1130 | size_t bufspace, long slept, | |
1131 | const struct entry *req) | |
1132 | { | |
1133 | static const int reserve = 256; | |
1134 | char *p = &buffer[0]; | |
1135 | ssize_t bytes = 0; | |
1136 | ssize_t bytes_tot = 0; | |
1137 | long us, sec; | |
1138 | long slept_ms; | |
1139 | int trace_fd; | |
1140 | ||
1141 | /* Save some space for the final string and final null char */ | |
1142 | bufspace = bufspace - reserve - 1; | |
1143 | ||
1144 | if (resize_msg != NULL && resize_msg->len > 0) { | |
1145 | bytes = resize_msg->len; | |
1146 | strncpy(p, resize_msg->buf, bytes); | |
1147 | bytes_tot += bytes; | |
1148 | p += bytes; | |
1149 | bufspace -= bytes; | |
1150 | } | |
1151 | ||
1152 | trace_fd = open(debug_tracefile, O_RDONLY); | |
1153 | ||
1154 | if (trace_fd < 0) { | |
1155 | warn("open() failed on %s", debug_tracefile); | |
1156 | return; | |
1157 | } | |
1158 | ||
1159 | sec = timestamp->tv_sec; | |
1160 | us = timestamp->tv_nsec / 1000; | |
1161 | ||
1162 | if (slept != 0) { | |
1163 | slept_ms = slept / 1000; | |
1164 | bytes = snprintf(p, bufspace, | |
1165 | "%ld.%06ld Latency %d randomly sleep for %ld ms before print\n", | |
1166 | sec, us, req->ticket, slept_ms); | |
1167 | } else { | |
1168 | bytes = snprintf(p, bufspace, | |
1169 | "%ld.%06ld Latency %d immediate print\n", sec, | |
1170 | us, req->ticket); | |
1171 | } | |
1172 | ||
1173 | if (bytes < 0) { | |
1174 | warn("snprintf() failed"); | |
1175 | return; | |
1176 | } | |
1177 | p += bytes; | |
1178 | bufspace -= bytes; | |
1179 | bytes_tot += bytes; | |
1180 | ||
1181 | bytes = snprintf(p, bufspace, | |
1182 | ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> BEGIN <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n" | |
1183 | ); | |
1184 | ||
1185 | if (bytes < 0) { | |
1186 | warn("snprintf() failed"); | |
1187 | return; | |
1188 | } | |
1189 | ||
1190 | p += bytes; | |
1191 | bufspace -= bytes; | |
1192 | bytes_tot += bytes; | |
1193 | ||
1194 | do { | |
1195 | bytes = read(trace_fd, p, bufspace); | |
1196 | if (bytes < 0) { | |
1197 | if (errno == EINTR) | |
1198 | continue; | |
1199 | warn("read() failed on %s", debug_tracefile); | |
1200 | if (unlikely(close(trace_fd) != 0)) | |
1201 | warn("close() failed on %s", debug_tracefile); | |
1202 | return; | |
1203 | } | |
1204 | if (bytes == 0) | |
1205 | break; | |
1206 | p += bytes; | |
1207 | bufspace -= bytes; | |
1208 | bytes_tot += bytes; | |
1209 | } while (true); | |
1210 | ||
1211 | if (unlikely(close(trace_fd) != 0)) | |
1212 | warn("close() failed on %s", debug_tracefile); | |
1213 | ||
1214 | printstate_cnt_dec(); | |
1215 | /* Add the reserve space back to the budget for the final string */ | |
1216 | bufspace += reserve; | |
1217 | ||
1218 | bytes = snprintf(p, bufspace, | |
1219 | ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> END <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n\n"); | |
1220 | ||
1221 | if (bytes < 0) { | |
1222 | warn("snprintf() failed"); | |
1223 | return; | |
1224 | } | |
1225 | ||
1226 | bytes_tot += bytes; | |
1227 | ||
1228 | /* These prints could happen concurrently */ | |
1229 | mutex_lock(&print_mtx); | |
1230 | write_or_die(fd_stdout, buffer, bytes_tot); | |
1231 | mutex_unlock(&print_mtx); | |
1232 | } | |
1233 | ||
1234 | static char *get_no_opt(const char *opt) | |
1235 | { | |
1236 | char *no_opt; | |
1237 | int s; | |
1238 | ||
1239 | s = strlen(opt) + strlen(OPT_NO_PREFIX) + 1; | |
1240 | /* We may be called from cleanup_exit() via set_trace_opt() */ | |
1241 | no_opt = malloc_or_die_nocleanup(s); | |
1242 | strcpy(no_opt, OPT_NO_PREFIX); | |
1243 | strcat(no_opt, opt); | |
1244 | return no_opt; | |
1245 | } | |
1246 | ||
1247 | static char *find_next_optstr(const char *allopt, const char **next) | |
1248 | { | |
1249 | const char *begin; | |
1250 | const char *end; | |
1251 | char *r; | |
1252 | int s = 0; | |
1253 | ||
1254 | if (allopt == NULL) | |
1255 | return NULL; | |
1256 | ||
1257 | for (begin = allopt; *begin != '\0'; begin++) { | |
1258 | if (isgraph(*begin)) | |
1259 | break; | |
1260 | } | |
1261 | ||
1262 | if (*begin == '\0') | |
1263 | return NULL; | |
1264 | ||
1265 | for (end = begin; *end != '\0' && isgraph(*end); end++) | |
1266 | s++; | |
1267 | ||
1268 | r = malloc_or_die_nocleanup(s + 1); | |
1269 | strncpy(r, begin, s); | |
1270 | r[s] = '\0'; | |
1271 | *next = begin + s; | |
1272 | return r; | |
1273 | } | |
1274 | ||
1275 | static bool get_trace_opt(const char *allopt, const char *opt, bool *found) | |
1276 | { | |
1277 | *found = false; | |
1278 | char *no_opt; | |
1279 | char *str; | |
1280 | const char *next = allopt; | |
1281 | bool rval = false; | |
1282 | ||
1283 | no_opt = get_no_opt(opt); | |
1284 | ||
1285 | do { | |
1286 | str = find_next_optstr(next, &next); | |
1287 | if (str == NULL) | |
1288 | break; | |
1289 | if (!strcmp(str, opt)) { | |
1290 | *found = true; | |
1291 | rval = true; | |
1292 | free(str); | |
1293 | break; | |
1294 | } | |
1295 | if (!strcmp(str, no_opt)) { | |
1296 | *found = true; | |
1297 | rval = false; | |
1298 | free(str); | |
1299 | break; | |
1300 | } | |
1301 | free(str); | |
1302 | } while (true); | |
1303 | free(no_opt); | |
1304 | ||
1305 | return rval; | |
1306 | } | |
1307 | ||
1308 | static int set_trace_opt(const char *opt, bool value) | |
1309 | { | |
1310 | char *str; | |
1311 | int r; | |
1312 | ||
1313 | if (value) | |
1314 | str = strdup(opt); | |
1315 | else | |
1316 | str = get_no_opt(opt); | |
1317 | ||
1318 | r = tracefs_instance_file_write(NULL, TR_OPTIONS, str); | |
1319 | free(str); | |
1320 | return r; | |
1321 | } | |
1322 | ||
1323 | void save_trace_opts(struct ftrace_state *state) | |
1324 | { | |
1325 | char *allopt; | |
1326 | int psize; | |
1327 | int i; | |
1328 | ||
1329 | allopt = tracefs_instance_file_read(NULL, TR_OPTIONS, &psize); | |
1330 | if (!allopt) | |
1331 | errx(EXIT_FAILURE, "Failed to read the %s file\n", TR_OPTIONS); | |
1332 | ||
1333 | for (i = 0; i < OPTIDX_NR; i++) | |
1334 | state->opt[i] = get_trace_opt(allopt, optstr[i], | |
1335 | &state->opt_valid[i]); | |
1336 | ||
1337 | free(allopt); | |
1338 | } | |
1339 | ||
1340 | static void write_file(const char *file, const char *cur, const char *new, | |
1341 | enum errhandling h) | |
1342 | { | |
1343 | int r; | |
1344 | static const char *emsg = "Failed to write to the %s file!"; | |
1345 | ||
1346 | /* Do nothing if we now that the current and new value are equal */ | |
1347 | if (cur && !needs_change(cur, new)) | |
1348 | return; | |
1349 | ||
1350 | r = tracefs_instance_file_write(NULL, file, new); | |
1351 | if (r < 0) { | |
1352 | if (h) { | |
1353 | warnx(emsg, file); | |
1354 | if (h == ERR_CLEANUP) | |
1355 | cleanup_exit(EXIT_FAILURE); | |
1356 | } else | |
1357 | errx(EXIT_FAILURE, emsg, file); | |
1358 | } | |
1359 | if (verbose_ftrace()) { | |
1360 | mutex_lock(&print_mtx); | |
1361 | printf("%s was set to %s\n", file, new); | |
1362 | mutex_unlock(&print_mtx); | |
1363 | } | |
1364 | } | |
1365 | ||
1366 | static void reset_max_latency(void) | |
1367 | { | |
1368 | write_file(TR_MAXLAT, NULL, "0", ERR_CLEANUP); | |
1369 | } | |
1370 | ||
1371 | static void save_and_disable_tracer(void) | |
1372 | { | |
1373 | char *orig_th; | |
1374 | char *tracer; | |
1375 | bool need_nop = false; | |
1376 | ||
1377 | mutex_lock(&save_state.mutex); | |
1378 | ||
1379 | save_trace_opts(&save_state); | |
1380 | tracer = read_file(TR_CURRENT, ERR_EXIT); | |
1381 | orig_th = read_file(TR_THRESH, ERR_EXIT); | |
1382 | ||
1383 | if (needs_change(tracer, NOP_TRACER)) { | |
1384 | mutex_lock(&print_mtx); | |
1385 | if (force_tracer) { | |
1386 | printf( | |
1387 | "The %s tracer is already in use but proceeding anyway!\n", | |
1388 | tracer); | |
1389 | } else { | |
1390 | printf( | |
1391 | "The %s tracer is already in use, cowardly bailing out!\n" | |
1392 | "This could indicate that another program or instance is tracing.\n" | |
1393 | "Use the -F [--force] option to disregard the current tracer.\n", tracer); | |
1394 | exit(0); | |
1395 | } | |
1396 | mutex_unlock(&print_mtx); | |
1397 | need_nop = true; | |
1398 | } | |
1399 | ||
1400 | save_state.tracer = tracer; | |
1401 | save_state.thresh = orig_th; | |
1402 | ||
1403 | if (need_nop) | |
1404 | write_file(TR_CURRENT, NULL, NOP_TRACER, ERR_EXIT); | |
1405 | ||
1406 | mutex_unlock(&save_state.mutex); | |
1407 | } | |
1408 | ||
1409 | void set_trace_opts(struct ftrace_state *state, bool *new) | |
1410 | { | |
1411 | int i; | |
1412 | int r; | |
1413 | ||
1414 | /* | |
1415 | * We only set options if we earlier detected that the option exists in | |
1416 | * the trace_options file and that the wanted setting is different from | |
1417 | * the one we saw in save_and_disable_tracer() | |
1418 | */ | |
1419 | for (i = 0; i < OPTIDX_NR; i++) | |
1420 | if (state->opt_valid[i] && | |
1421 | state->opt[i] != new[i]) { | |
1422 | r = set_trace_opt(optstr[i], new[i]); | |
1423 | if (r < 0) { | |
1424 | warnx("Failed to set the %s option to %s", | |
1425 | optstr[i], bool2str(new[i])); | |
1426 | cleanup_exit(EXIT_FAILURE); | |
1427 | } | |
1428 | if (verbose_ftrace()) { | |
1429 | mutex_lock(&print_mtx); | |
1430 | printf("%s in %s was set to %s\n", optstr[i], | |
1431 | TR_OPTIONS, bool2str(new[i])); | |
1432 | mutex_unlock(&print_mtx); | |
1433 | } | |
1434 | } | |
1435 | } | |
1436 | ||
1437 | static void enable_tracer(void) | |
1438 | { | |
1439 | mutex_lock(&save_state.mutex); | |
1440 | set_trace_opts(&save_state, use_options); | |
1441 | ||
1442 | write_file(TR_THRESH, save_state.thresh, threshold, ERR_CLEANUP); | |
1443 | write_file(TR_CURRENT, NOP_TRACER, current_tracer, ERR_CLEANUP); | |
1444 | ||
1445 | mutex_unlock(&save_state.mutex); | |
1446 | } | |
1447 | ||
1448 | static void tracing_loop(void) | |
1449 | { | |
1450 | int ifd = inotify_init(); | |
1451 | int wd; | |
1452 | const ssize_t bufsize = sizeof(inotify_buffer); | |
1453 | const ssize_t istructsize = sizeof(struct inotify_event); | |
1454 | char *buf = &inotify_buffer[0]; | |
1455 | ssize_t nr_read; | |
1456 | char *p; | |
1457 | int modified; | |
1458 | struct inotify_event *event; | |
1459 | struct entry req; | |
1460 | char *buffer; | |
1461 | const size_t bufspace = PRINT_BUFFER_SIZE; | |
1462 | struct timespec timestamp; | |
1463 | ||
1464 | print_priority(); | |
1465 | ||
1466 | buffer = malloc_or_die(bufspace); | |
1467 | ||
1468 | if (ifd < 0) | |
1469 | err(EXIT_FAILURE, "inotify_init() failed!"); | |
1470 | ||
1471 | ||
1472 | if (setup_ftrace) { | |
1473 | /* | |
1474 | * We must disable the tracer before resetting the max_latency | |
1475 | */ | |
1476 | save_and_disable_tracer(); | |
1477 | /* | |
1478 | * We must reset the max_latency before the inotify_add_watch() | |
1479 | * call. | |
1480 | */ | |
1481 | reset_max_latency(); | |
1482 | } | |
1483 | ||
1484 | wd = inotify_add_watch(ifd, debug_maxlat, IN_MODIFY); | |
1485 | if (wd < 0) | |
1486 | err(EXIT_FAILURE, "inotify_add_watch() failed!"); | |
1487 | ||
1488 | if (setup_ftrace) | |
1489 | enable_tracer(); | |
1490 | ||
1491 | signal_blocking(SIG_UNBLOCK); | |
1492 | ||
1493 | while (true) { | |
1494 | modified = 0; | |
1495 | check_signals(); | |
1496 | nr_read = read(ifd, buf, bufsize); | |
1497 | check_signals(); | |
1498 | if (nr_read < 0) { | |
1499 | if (errno == EINTR) | |
1500 | continue; | |
1501 | warn("read() failed on inotify fd!"); | |
1502 | cleanup_exit(EXIT_FAILURE); | |
1503 | } | |
1504 | if (nr_read == bufsize) | |
1505 | warnx("inotify() buffer filled, skipping events"); | |
1506 | if (nr_read < istructsize) { | |
1507 | warnx("read() returned too few bytes on inotify fd"); | |
1508 | cleanup_exit(EXIT_FAILURE); | |
1509 | } | |
1510 | ||
1511 | for (p = buf; p < buf + nr_read;) { | |
1512 | event = (struct inotify_event *) p; | |
1513 | if ((event->mask & IN_MODIFY) != 0) | |
1514 | modified++; | |
1515 | p += istructsize + event->len; | |
1516 | } | |
1517 | while (modified > 0) { | |
1518 | check_signals(); | |
1519 | mutex_lock(&printstate.mutex); | |
1520 | check_signals(); | |
1521 | printstate_next_ticket(&req); | |
1522 | if (printstate_cnt_read() > 0) { | |
1523 | printstate_mark_req_completed(&req); | |
1524 | mutex_unlock(&printstate.mutex); | |
1525 | if (verbose_lostevent()) { | |
1526 | clock_gettime_or_die(CLOCK_MONOTONIC, | |
1527 | ×tamp); | |
1528 | print_lostmessage(×tamp, buffer, | |
1529 | bufspace, &req, | |
1530 | "inotify loop"); | |
1531 | } | |
1532 | break; | |
1533 | } | |
1534 | mutex_unlock(&printstate.mutex); | |
1535 | if (queue_try_to_add_entry(&printqueue, &req) != 0) { | |
1536 | /* These prints could happen concurrently */ | |
1537 | check_signals(); | |
1538 | mutex_lock(&print_mtx); | |
1539 | check_signals(); | |
1540 | write_or_die(fd_stdout, queue_full_warning, | |
f604de20 | 1541 | strlen(queue_full_warning)); |
e23db805 VR |
1542 | mutex_unlock(&print_mtx); |
1543 | } | |
1544 | modified--; | |
1545 | } | |
1546 | } | |
1547 | } | |
1548 | ||
1549 | static void *do_printloop(void *arg) | |
1550 | { | |
1551 | const size_t bufspace = PRINT_BUFFER_SIZE; | |
1552 | char *buffer; | |
1553 | long *rseed = (long *) arg; | |
1554 | struct drand48_data drandbuf; | |
1555 | long slept = 0; | |
1556 | struct entry req; | |
1557 | int prob = 0; | |
1558 | struct timespec timestamp; | |
1559 | struct short_msg resize_msg; | |
1560 | ||
1561 | print_priority(); | |
1562 | ||
1563 | if (srand48_r(*rseed, &drandbuf) != 0) { | |
1564 | warn("srand48_r() failed!\n"); | |
1565 | cleanup_exit(EXIT_FAILURE); | |
1566 | } | |
1567 | ||
1568 | buffer = malloc_or_die(bufspace); | |
1569 | ||
1570 | while (true) { | |
1571 | req = queue_wait_for_entry(&printqueue); | |
1572 | clock_gettime_or_die(CLOCK_MONOTONIC, ×tamp); | |
1573 | mutex_lock(&printstate.mutex); | |
1574 | if (prev_req_won_race(&req)) { | |
1575 | printstate_mark_req_completed(&req); | |
1576 | mutex_unlock(&printstate.mutex); | |
1577 | if (verbose_lostevent()) | |
1578 | print_lostmessage(×tamp, buffer, bufspace, | |
1579 | &req, "print loop"); | |
1580 | continue; | |
1581 | } | |
1582 | mutex_unlock(&printstate.mutex); | |
1583 | ||
1584 | /* | |
1585 | * Toss a coin to decide if we want to sleep before printing | |
1586 | * out the backtrace. The reason for this is that opening | |
2455f0e1 | 1587 | * /sys/kernel/tracing/trace will cause a blackout of |
e23db805 VR |
1588 | * hundreds of ms, where no latencies will be noted by the |
1589 | * latency tracer. Thus by randomly sleeping we try to avoid | |
1590 | * missing traces systematically due to this. With this option | |
1591 | * we will sometimes get the first latency, some other times | |
1592 | * some of the later ones, in case of closely spaced traces. | |
1593 | */ | |
1594 | if (trace_enable && use_random_sleep) { | |
1595 | slept = 0; | |
1596 | prob = table_get_probability(&req, &resize_msg); | |
1597 | if (!toss_coin(&drandbuf, prob)) | |
1598 | slept = go_to_sleep(&req); | |
1599 | if (slept >= 0) { | |
1600 | /* A print is ongoing */ | |
1601 | printstate_cnt_inc(); | |
1602 | /* | |
1603 | * We will do the printout below so we have to | |
1604 | * mark it as completed while we still have the | |
1605 | * mutex. | |
1606 | */ | |
1607 | mutex_lock(&printstate.mutex); | |
1608 | printstate_mark_req_completed(&req); | |
1609 | mutex_unlock(&printstate.mutex); | |
1610 | } | |
1611 | } | |
1612 | if (trace_enable) { | |
1613 | /* | |
1614 | * slept < 0 means that we detected another | |
1615 | * notification in go_to_sleep() above | |
1616 | */ | |
1617 | if (slept >= 0) | |
1618 | /* | |
1619 | * N.B. printstate_cnt_dec(); will be called | |
1620 | * inside print_tracefile() | |
1621 | */ | |
1622 | print_tracefile(&resize_msg, ×tamp, buffer, | |
1623 | bufspace, slept, &req); | |
1624 | else | |
1625 | print_skipmessage(&resize_msg, ×tamp, | |
1626 | buffer, bufspace, &req, true); | |
1627 | } else { | |
1628 | print_skipmessage(&resize_msg, ×tamp, buffer, | |
1629 | bufspace, &req, false); | |
1630 | } | |
1631 | } | |
1632 | return NULL; | |
1633 | } | |
1634 | ||
1635 | static void start_printthread(void) | |
1636 | { | |
1637 | unsigned int i; | |
1638 | long *seed; | |
1639 | int ufd; | |
1640 | ||
1641 | ufd = open(DEV_URANDOM, O_RDONLY); | |
1642 | if (nr_threads > MAX_THREADS) { | |
1643 | warnx( | |
1644 | "Number of requested print threads was %d, max number is %d\n", | |
1645 | nr_threads, MAX_THREADS); | |
1646 | nr_threads = MAX_THREADS; | |
1647 | } | |
1648 | for (i = 0; i < nr_threads; i++) { | |
1649 | seed = malloc_or_die(sizeof(*seed)); | |
1650 | if (ufd < 0 || | |
1651 | read(ufd, seed, sizeof(*seed)) != sizeof(*seed)) { | |
1652 | printf( | |
c1d96fa6 | 1653 | "Warning! Using trivial random number seed, since %s not available\n", |
e23db805 VR |
1654 | DEV_URANDOM); |
1655 | fflush(stdout); | |
1656 | *seed = i; | |
1657 | } | |
1658 | errno = pthread_create(&printthread[i], NULL, do_printloop, | |
1659 | seed); | |
1660 | if (errno) | |
1661 | err(EXIT_FAILURE, "pthread_create()"); | |
1662 | } | |
1663 | if (ufd > 0 && close(ufd) != 0) | |
1664 | warn("close() failed"); | |
1665 | } | |
1666 | ||
1667 | static void show_usage(void) | |
1668 | { | |
1669 | printf( | |
1670 | "Usage: %s [OPTION]...\n\n" | |
1671 | "Collect closely occurring latencies from %s\n" | |
1672 | "with any of the following tracers: preemptirqsoff, preemptoff, irqsoff, " | |
1673 | "wakeup,\nwakeup_dl, or wakeup_rt.\n\n" | |
1674 | ||
1675 | "The occurrence of a latency is detected by monitoring the file\n" | |
1676 | "%s with inotify.\n\n" | |
1677 | ||
1678 | "The following options are supported:\n\n" | |
1679 | ||
1680 | "-l, --list\t\tList the latency tracers that are supported by the\n" | |
1681 | "\t\t\tcurrently running Linux kernel. If you don't see the\n" | |
1682 | "\t\t\ttracer that you want, you will probably need to\n" | |
1683 | "\t\t\tchange your kernel config and build a new kernel.\n\n" | |
1684 | ||
1685 | "-t, --tracer TR\t\tUse the tracer TR. The default is to use the first\n" | |
1686 | "\t\t\ttracer that is supported by the kernel in the following\n" | |
1687 | "\t\t\torder of precedence:\n\n" | |
1688 | "\t\t\tpreemptirqsoff\n" | |
1689 | "\t\t\tpreemptoff\n" | |
1690 | "\t\t\tirqsoff\n" | |
1691 | "\t\t\twakeup\n" | |
1692 | "\t\t\twakeup_rt\n" | |
1693 | "\t\t\twakeup_dl\n" | |
1694 | "\n" | |
1695 | "\t\t\tIf TR is not on the list above, then a warning will be\n" | |
1696 | "\t\t\tprinted.\n\n" | |
1697 | ||
1698 | "-F, --force\t\tProceed even if another ftrace tracer is active. Without\n" | |
1699 | "\t\t\tthis option, the program will refuse to start tracing if\n" | |
1700 | "\t\t\tany other tracer than the nop tracer is active.\n\n" | |
1701 | ||
1702 | "-s, --threshold TH\tConfigure ftrace to use a threshold of TH microseconds\n" | |
1703 | "\t\t\tfor the tracer. The default is 0, which means that\n" | |
1704 | "\t\t\ttracing_max_latency will be used. tracing_max_latency is\n" | |
1705 | "\t\t\tset to 0 when the program is started and contains the\n" | |
1706 | "\t\t\tmaximum of the latencies that have been encountered.\n\n" | |
1707 | ||
1708 | "-f, --function\t\tEnable the function-trace option in trace_options. With\n" | |
1709 | "\t\t\tthis option, ftrace will trace the functions that are\n" | |
1710 | "\t\t\texecuted during a latency, without it we only get the\n" | |
1711 | "\t\t\tbeginning, end, and backtrace.\n\n" | |
1712 | ||
1713 | "-g, --graph\t\tEnable the display-graph option in trace_option. This\n" | |
c1d96fa6 CIK |
1714 | "\t\t\toption causes ftrace to show the graph of how functions\n" |
1715 | "\t\t\tare calling other functions.\n\n" | |
e23db805 VR |
1716 | |
1717 | "-c, --policy POL\tRun the program with scheduling policy POL. POL can be\n" | |
1718 | "\t\t\tother, batch, idle, rr or fifo. The default is rr. When\n" | |
1719 | "\t\t\tusing rr or fifo, remember that these policies may cause\n" | |
1720 | "\t\t\tother tasks to experience latencies.\n\n" | |
1721 | ||
1722 | "-p, --priority PRI\tRun the program with priority PRI. The acceptable range\n" | |
1723 | "\t\t\tof PRI depends on the scheduling policy.\n\n" | |
1724 | ||
1725 | "-n, --notrace\t\tIf latency is detected, do not print out the content of\n" | |
1726 | "\t\t\tthe trace file to standard output\n\n" | |
1727 | ||
1728 | "-t, --threads NRTHR\tRun NRTHR threads for printing. Default is %d.\n\n" | |
1729 | ||
1730 | "-r, --random\t\tArbitrarily sleep a certain amount of time, default\n" | |
1731 | "\t\t\t%ld ms, before reading the trace file. The\n" | |
1732 | "\t\t\tprobabilities for sleep are chosen so that the\n" | |
1733 | "\t\t\tprobability of obtaining any of a cluster of closely\n" | |
1734 | "\t\t\toccurring latencies are equal, i.e. we will randomly\n" | |
1735 | "\t\t\tchoose which one we collect from the trace file.\n\n" | |
1736 | "\t\t\tThis option is probably only useful with the irqsoff,\n" | |
1737 | "\t\t\tpreemptoff, and preemptirqsoff tracers.\n\n" | |
1738 | ||
1739 | "-a, --nrlat NRLAT\tFor the purpose of arbitrary delay, assume that there\n" | |
1740 | "\t\t\tare no more than NRLAT clustered latencies. If NRLAT\n" | |
1741 | "\t\t\tlatencies are detected during a run, this value will\n" | |
1742 | "\t\t\tautomatically be increased to NRLAT + 1 and then to\n" | |
1743 | "\t\t\tNRLAT + 2 and so on. The default is %d. This option\n" | |
1744 | "\t\t\timplies -r. We need to know this number in order to\n" | |
1745 | "\t\t\tbe able to calculate the probabilities of sleeping.\n" | |
1746 | "\t\t\tSpecifically, the probabilities of not sleeping, i.e. to\n" | |
1747 | "\t\t\tdo an immediate printout will be:\n\n" | |
1748 | "\t\t\t1/NRLAT 1/(NRLAT - 1) ... 1/3 1/2 1\n\n" | |
1749 | "\t\t\tThe probability of sleeping will be:\n\n" | |
1750 | "\t\t\t1 - P, where P is from the series above\n\n" | |
1751 | "\t\t\tThis descending probability will cause us to choose\n" | |
1752 | "\t\t\tan occurrence at random. Observe that the final\n" | |
1753 | "\t\t\tprobability is 0, it is when we reach this probability\n" | |
1754 | "\t\t\tthat we increase NRLAT automatically. As an example,\n" | |
1755 | "\t\t\twith the default value of 2, the probabilities will be:\n\n" | |
1756 | "\t\t\t1/2 0\n\n" | |
1757 | "\t\t\tThis means, when a latency is detected we will sleep\n" | |
1758 | "\t\t\twith 50%% probability. If we ever detect another latency\n" | |
1759 | "\t\t\tduring the sleep period, then the probability of sleep\n" | |
1760 | "\t\t\twill be 0%% and the table will be expanded to:\n\n" | |
1761 | "\t\t\t1/3 1/2 0\n\n" | |
1762 | ||
1763 | "-v, --verbose\t\tIncrease the verbosity. If this option is given once,\n" | |
1764 | "\t\t\tthen print a message every time that the NRLAT value\n" | |
1765 | "\t\t\tis automatically increased. It also causes a message to\n" | |
1766 | "\t\t\tbe printed when the ftrace settings are changed. If this\n" | |
1767 | "\t\t\toption is given at least twice, then also print a\n" | |
1768 | "\t\t\twarning for lost events.\n\n" | |
1769 | ||
1770 | "-u, --time TIME\t\tArbitrarily sleep for a specified time TIME ms before\n" | |
1771 | "\t\t\tprinting out the trace from the trace file. The default\n" | |
1772 | "\t\t\tis %ld ms. This option implies -r.\n\n" | |
1773 | ||
1774 | "-x, --no-ftrace\t\tDo not configure ftrace. This assume that the user\n" | |
1775 | "\t\t\tconfigures the ftrace files in sysfs such as\n" | |
1776 | "\t\t\t/sys/kernel/tracing/current_tracer or equivalent.\n\n" | |
1777 | ||
1778 | "-i, --tracefile FILE\tUse FILE as trace file. The default is\n" | |
1779 | "\t\t\t%s.\n" | |
1780 | "\t\t\tThis options implies -x\n\n" | |
1781 | ||
1782 | "-m, --max-lat FILE\tUse FILE as tracing_max_latency file. The default is\n" | |
1783 | "\t\t\t%s.\n" | |
1784 | "\t\t\tThis options implies -x\n\n" | |
1785 | , | |
1786 | prg_name, debug_tracefile_dflt, debug_maxlat_dflt, DEFAULT_NR_PRINTER_THREADS, | |
1787 | SLEEP_TIME_MS_DEFAULT, DEFAULT_TABLE_SIZE, SLEEP_TIME_MS_DEFAULT, | |
1788 | debug_tracefile_dflt, debug_maxlat_dflt); | |
1789 | } | |
1790 | ||
1791 | static void find_tracefiles(void) | |
1792 | { | |
1793 | debug_tracefile_dflt = tracefs_get_tracing_file("trace"); | |
1794 | if (debug_tracefile_dflt == NULL) { | |
1795 | /* This is needed in show_usage() */ | |
1796 | debug_tracefile_dflt = DEBUG_NOFILE; | |
1797 | } | |
1798 | ||
1799 | debug_maxlat_dflt = tracefs_get_tracing_file("tracing_max_latency"); | |
1800 | if (debug_maxlat_dflt == NULL) { | |
1801 | /* This is needed in show_usage() */ | |
1802 | debug_maxlat_dflt = DEBUG_NOFILE; | |
1803 | } | |
1804 | ||
1805 | debug_tracefile = debug_tracefile_dflt; | |
1806 | debug_maxlat = debug_maxlat_dflt; | |
1807 | } | |
1808 | ||
1809 | bool alldigits(const char *s) | |
1810 | { | |
1811 | for (; *s != '\0'; s++) | |
1812 | if (!isdigit(*s)) | |
1813 | return false; | |
1814 | return true; | |
1815 | } | |
1816 | ||
1817 | void check_alldigits(const char *optarg, const char *argname) | |
1818 | { | |
1819 | if (!alldigits(optarg)) | |
1820 | errx(EXIT_FAILURE, | |
1821 | "The %s parameter expects a decimal argument\n", argname); | |
1822 | } | |
1823 | ||
1824 | static void scan_arguments(int argc, char *argv[]) | |
1825 | { | |
1826 | int c; | |
1827 | int i; | |
1828 | int option_idx = 0; | |
1829 | ||
1830 | static struct option long_options[] = { | |
1831 | { "list", no_argument, 0, 'l' }, | |
1832 | { "tracer", required_argument, 0, 't' }, | |
1833 | { "force", no_argument, 0, 'F' }, | |
1834 | { "threshold", required_argument, 0, 's' }, | |
1835 | { "function", no_argument, 0, 'f' }, | |
1836 | { "graph", no_argument, 0, 'g' }, | |
1837 | { "policy", required_argument, 0, 'c' }, | |
1838 | { "priority", required_argument, 0, 'p' }, | |
1839 | { "help", no_argument, 0, 'h' }, | |
1840 | { "notrace", no_argument, 0, 'n' }, | |
1841 | { "random", no_argument, 0, 'r' }, | |
1842 | { "nrlat", required_argument, 0, 'a' }, | |
1843 | { "threads", required_argument, 0, 'e' }, | |
1844 | { "time", required_argument, 0, 'u' }, | |
1845 | { "verbose", no_argument, 0, 'v' }, | |
1846 | { "no-ftrace", no_argument, 0, 'x' }, | |
1847 | { "tracefile", required_argument, 0, 'i' }, | |
1848 | { "max-lat", required_argument, 0, 'm' }, | |
1849 | { 0, 0, 0, 0 } | |
1850 | }; | |
1851 | const struct policy *p; | |
1852 | int max, min; | |
1853 | int value; | |
1854 | bool notracer, valid; | |
1855 | ||
1856 | /* | |
1857 | * We must do this before parsing the arguments because show_usage() | |
1858 | * needs to display these. | |
1859 | */ | |
1860 | find_tracefiles(); | |
1861 | ||
1862 | while (true) { | |
1863 | c = getopt_long(argc, argv, "lt:Fs:fgc:p:hnra:e:u:vxi:m:", | |
1864 | long_options, &option_idx); | |
1865 | if (c == -1) | |
1866 | break; | |
1867 | ||
1868 | switch (c) { | |
1869 | case 'l': | |
1870 | show_available(); | |
1871 | exit(0); | |
1872 | break; | |
1873 | case 't': | |
1874 | current_tracer = strdup(optarg); | |
1875 | if (!is_relevant_tracer(current_tracer)) { | |
1876 | warnx("%s is not a known latency tracer!\n", | |
1877 | current_tracer); | |
1878 | } | |
1879 | valid = tracer_valid(current_tracer, ¬racer); | |
1880 | if (notracer) | |
df73757c | 1881 | errx(EXIT_FAILURE, "%s", no_tracer_msg); |
e23db805 VR |
1882 | if (!valid) |
1883 | errx(EXIT_FAILURE, | |
1884 | "The tracer %s is not supported by your kernel!\n", current_tracer); | |
1885 | break; | |
1886 | case 'F': | |
1887 | force_tracer = true; | |
1888 | break; | |
1889 | case 's': | |
1890 | check_alldigits(optarg, "-s [--threshold]"); | |
1891 | threshold = strdup(optarg); | |
1892 | break; | |
1893 | case 'f': | |
1894 | use_options[OPTIDX_FUNC_TR] = true; | |
1895 | break; | |
1896 | case 'g': | |
1897 | use_options[OPTIDX_DISP_GR] = true; | |
1898 | break; | |
1899 | case 'c': | |
1900 | p = policy_from_name(optarg); | |
1901 | if (p != NULL) { | |
1902 | sched_policy = p->policy; | |
1903 | sched_policy_set = true; | |
1904 | if (!sched_pri_set) { | |
1905 | sched_pri = p->default_pri; | |
1906 | sched_pri_set = true; | |
1907 | } | |
1908 | } else { | |
1909 | warnx("Unknown scheduling %s\n", optarg); | |
1910 | show_usage(); | |
1911 | exit(0); | |
1912 | } | |
1913 | break; | |
1914 | case 'p': | |
1915 | check_alldigits(optarg, "-p [--priority]"); | |
1916 | sched_pri = atoi(optarg); | |
1917 | sched_pri_set = true; | |
1918 | break; | |
1919 | case 'h': | |
1920 | show_usage(); | |
1921 | exit(0); | |
1922 | break; | |
1923 | case 'n': | |
1924 | trace_enable = false; | |
1925 | use_random_sleep = false; | |
1926 | break; | |
1927 | case 'e': | |
1928 | check_alldigits(optarg, "-e [--threads]"); | |
1929 | value = atoi(optarg); | |
1930 | if (value > 0) | |
1931 | nr_threads = value; | |
1932 | else { | |
1933 | warnx("NRTHR must be > 0\n"); | |
1934 | show_usage(); | |
1935 | exit(0); | |
1936 | } | |
1937 | break; | |
1938 | case 'u': | |
1939 | check_alldigits(optarg, "-u [--time]"); | |
1940 | value = atoi(optarg); | |
1941 | if (value < 0) { | |
1942 | warnx("TIME must be >= 0\n"); | |
1943 | show_usage(); | |
421d9d1b | 1944 | exit(0); |
e23db805 VR |
1945 | } |
1946 | trace_enable = true; | |
1947 | use_random_sleep = true; | |
1948 | sleep_time = value * USEC_PER_MSEC; | |
1949 | break; | |
1950 | case 'v': | |
1951 | verbosity++; | |
1952 | break; | |
1953 | case 'r': | |
1954 | trace_enable = true; | |
1955 | use_random_sleep = true; | |
1956 | break; | |
1957 | case 'a': | |
1958 | check_alldigits(optarg, "-a [--nrlat]"); | |
1959 | value = atoi(optarg); | |
1960 | if (value <= 0) { | |
1961 | warnx("NRLAT must be > 0\n"); | |
1962 | show_usage(); | |
1963 | exit(0); | |
1964 | } | |
1965 | trace_enable = true; | |
1966 | use_random_sleep = true; | |
1967 | table_startsize = value; | |
1968 | break; | |
1969 | case 'x': | |
1970 | setup_ftrace = false; | |
1971 | break; | |
1972 | case 'i': | |
1973 | setup_ftrace = false; | |
1974 | debug_tracefile = strdup(optarg); | |
1975 | break; | |
1976 | case 'm': | |
1977 | setup_ftrace = false; | |
1978 | debug_maxlat = strdup(optarg); | |
1979 | break; | |
1980 | default: | |
1981 | show_usage(); | |
1982 | exit(0); | |
1983 | break; | |
1984 | } | |
1985 | } | |
1986 | ||
1987 | if (setup_ftrace) { | |
1988 | if (!current_tracer) { | |
1989 | current_tracer = find_default_tracer(); | |
1990 | if (!current_tracer) | |
1991 | errx(EXIT_FAILURE, | |
1992 | "No default tracer found and tracer not specified\n"); | |
1993 | } | |
1994 | ||
1995 | if (use_random_sleep && !random_makes_sense(current_tracer)) { | |
1996 | warnx("WARNING: The tracer is %s and random sleep has", | |
1997 | current_tracer); | |
1998 | fprintf(stderr, | |
1999 | "been enabled. Random sleep is intended for the following tracers:\n"); | |
2000 | for (i = 0; random_tracers[i]; i++) | |
2001 | fprintf(stderr, "%s\n", random_tracers[i]); | |
2002 | fprintf(stderr, "\n"); | |
2003 | } | |
2004 | } | |
2005 | ||
2006 | if (debug_tracefile == DEBUG_NOFILE || | |
2007 | debug_maxlat == DEBUG_NOFILE) | |
2008 | errx(EXIT_FAILURE, | |
2009 | "Could not find tracing directory e.g. /sys/kernel/tracing\n"); | |
2010 | ||
2011 | if (!sched_policy_set) { | |
2012 | sched_policy = SCHED_RR; | |
2013 | sched_policy_set = true; | |
2014 | if (!sched_pri_set) { | |
2015 | sched_pri = RT_DEFAULT_PRI; | |
2016 | sched_pri_set = true; | |
2017 | } | |
2018 | } | |
2019 | ||
2020 | max = sched_get_priority_max(sched_policy); | |
2021 | min = sched_get_priority_min(sched_policy); | |
2022 | ||
2023 | if (sched_pri < min) { | |
2024 | printf( | |
2025 | "ATTENTION: Increasing priority to minimum, which is %d\n", min); | |
2026 | sched_pri = min; | |
2027 | } | |
2028 | if (sched_pri > max) { | |
2029 | printf( | |
2030 | "ATTENTION: Reducing priority to maximum, which is %d\n", max); | |
2031 | sched_pri = max; | |
2032 | } | |
2033 | } | |
2034 | ||
2035 | static void show_params(void) | |
2036 | { | |
2037 | printf( | |
2038 | "\n" | |
2039 | "Running with scheduling policy %s and priority %d. Using %d print threads.\n", | |
2040 | policy_name(sched_policy), sched_pri, nr_threads); | |
2041 | if (trace_enable) { | |
2042 | if (use_random_sleep) { | |
2043 | printf( | |
2044 | "%s will be printed with random delay\n" | |
2045 | "Start size of the probability table:\t\t\t%d\n" | |
2046 | "Print a message when the prob. table changes size:\t%s\n" | |
2047 | "Print a warning when an event has been lost:\t\t%s\n" | |
2048 | "Sleep time is:\t\t\t\t\t\t%ld ms\n", | |
2049 | debug_tracefile, | |
2050 | table_startsize, | |
2051 | bool2str(verbose_sizechange()), | |
2052 | bool2str(verbose_lostevent()), | |
2053 | sleep_time / USEC_PER_MSEC); | |
2054 | } else { | |
2055 | printf("%s will be printed immediately\n", | |
2056 | debug_tracefile); | |
2057 | } | |
2058 | } else { | |
2059 | printf("%s will not be printed\n", | |
2060 | debug_tracefile); | |
2061 | } | |
2062 | if (setup_ftrace) { | |
2063 | printf("Tracer:\t\t\t\t\t\t\t%s\n" | |
2064 | "%s option:\t\t\t\t\t%s\n" | |
2065 | "%s option:\t\t\t\t\t%s\n", | |
2066 | current_tracer, | |
2067 | optstr[OPTIDX_FUNC_TR], | |
2068 | bool2str(use_options[OPTIDX_FUNC_TR]), | |
2069 | optstr[OPTIDX_DISP_GR], | |
2070 | bool2str(use_options[OPTIDX_DISP_GR])); | |
2071 | if (!strcmp(threshold, "0")) | |
2072 | printf("Threshold:\t\t\t\t\t\ttracing_max_latency\n"); | |
2073 | else | |
2074 | printf("Threshold:\t\t\t\t\t\t%s\n", threshold); | |
2075 | } | |
2076 | printf("\n"); | |
2077 | } | |
2078 | ||
2079 | int main(int argc, char *argv[]) | |
2080 | { | |
2081 | init_save_state(); | |
2082 | signal_blocking(SIG_BLOCK); | |
2083 | setup_sig_handler(); | |
2084 | open_stdout(); | |
2085 | ||
2086 | if (argc >= 1) | |
2087 | prg_name = argv[0]; | |
2088 | else | |
2089 | prg_name = prg_unknown; | |
2090 | ||
2091 | scan_arguments(argc, argv); | |
2092 | show_params(); | |
2093 | ||
2094 | init_printstate(); | |
2095 | init_print_mtx(); | |
2096 | if (use_random_sleep) { | |
2097 | init_probabilities(); | |
2098 | if (verbose_sizechange()) | |
2099 | printf("Initializing probability table to %d\n", | |
2100 | table_startsize); | |
2101 | sleeptable_resize(table_startsize, false, NULL); | |
2102 | } | |
2103 | set_priority(); | |
2104 | init_queue(&printqueue); | |
2105 | start_printthread(); | |
2106 | tracing_loop(); | |
2107 | return 0; | |
2108 | } |