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Linux/tools/perf/util/evlist.c

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  1 /*
  2  * Copyright (C) 2011, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
  3  *
  4  * Parts came from builtin-{top,stat,record}.c, see those files for further
  5  * copyright notes.
  6  *
  7  * Released under the GPL v2. (and only v2, not any later version)
  8  */
  9 #include "util.h"
 10 #include <api/fs/fs.h>
 11 #include <poll.h>
 12 #include "cpumap.h"
 13 #include "thread_map.h"
 14 #include "target.h"
 15 #include "evlist.h"
 16 #include "evsel.h"
 17 #include "debug.h"
 18 #include <unistd.h>
 19 
 20 #include "parse-events.h"
 21 #include "parse-options.h"
 22 
 23 #include <sys/mman.h>
 24 
 25 #include <linux/bitops.h>
 26 #include <linux/hash.h>
 27 #include <linux/log2.h>
 28 
 29 static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx);
 30 static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx);
 31 
 32 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
 33 #define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
 34 
 35 void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
 36                        struct thread_map *threads)
 37 {
 38         int i;
 39 
 40         for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
 41                 INIT_HLIST_HEAD(&evlist->heads[i]);
 42         INIT_LIST_HEAD(&evlist->entries);
 43         perf_evlist__set_maps(evlist, cpus, threads);
 44         fdarray__init(&evlist->pollfd, 64);
 45         evlist->workload.pid = -1;
 46 }
 47 
 48 struct perf_evlist *perf_evlist__new(void)
 49 {
 50         struct perf_evlist *evlist = zalloc(sizeof(*evlist));
 51 
 52         if (evlist != NULL)
 53                 perf_evlist__init(evlist, NULL, NULL);
 54 
 55         return evlist;
 56 }
 57 
 58 struct perf_evlist *perf_evlist__new_default(void)
 59 {
 60         struct perf_evlist *evlist = perf_evlist__new();
 61 
 62         if (evlist && perf_evlist__add_default(evlist)) {
 63                 perf_evlist__delete(evlist);
 64                 evlist = NULL;
 65         }
 66 
 67         return evlist;
 68 }
 69 
 70 /**
 71  * perf_evlist__set_id_pos - set the positions of event ids.
 72  * @evlist: selected event list
 73  *
 74  * Events with compatible sample types all have the same id_pos
 75  * and is_pos.  For convenience, put a copy on evlist.
 76  */
 77 void perf_evlist__set_id_pos(struct perf_evlist *evlist)
 78 {
 79         struct perf_evsel *first = perf_evlist__first(evlist);
 80 
 81         evlist->id_pos = first->id_pos;
 82         evlist->is_pos = first->is_pos;
 83 }
 84 
 85 static void perf_evlist__update_id_pos(struct perf_evlist *evlist)
 86 {
 87         struct perf_evsel *evsel;
 88 
 89         evlist__for_each(evlist, evsel)
 90                 perf_evsel__calc_id_pos(evsel);
 91 
 92         perf_evlist__set_id_pos(evlist);
 93 }
 94 
 95 static void perf_evlist__purge(struct perf_evlist *evlist)
 96 {
 97         struct perf_evsel *pos, *n;
 98 
 99         evlist__for_each_safe(evlist, n, pos) {
100                 list_del_init(&pos->node);
101                 perf_evsel__delete(pos);
102         }
103 
104         evlist->nr_entries = 0;
105 }
106 
107 void perf_evlist__exit(struct perf_evlist *evlist)
108 {
109         zfree(&evlist->mmap);
110         fdarray__exit(&evlist->pollfd);
111 }
112 
113 void perf_evlist__delete(struct perf_evlist *evlist)
114 {
115         perf_evlist__munmap(evlist);
116         perf_evlist__close(evlist);
117         cpu_map__put(evlist->cpus);
118         thread_map__put(evlist->threads);
119         evlist->cpus = NULL;
120         evlist->threads = NULL;
121         perf_evlist__purge(evlist);
122         perf_evlist__exit(evlist);
123         free(evlist);
124 }
125 
126 void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry)
127 {
128         list_add_tail(&entry->node, &evlist->entries);
129         entry->idx = evlist->nr_entries;
130         entry->tracking = !entry->idx;
131 
132         if (!evlist->nr_entries++)
133                 perf_evlist__set_id_pos(evlist);
134 }
135 
136 void perf_evlist__splice_list_tail(struct perf_evlist *evlist,
137                                    struct list_head *list,
138                                    int nr_entries)
139 {
140         bool set_id_pos = !evlist->nr_entries;
141 
142         list_splice_tail(list, &evlist->entries);
143         evlist->nr_entries += nr_entries;
144         if (set_id_pos)
145                 perf_evlist__set_id_pos(evlist);
146 }
147 
148 void __perf_evlist__set_leader(struct list_head *list)
149 {
150         struct perf_evsel *evsel, *leader;
151 
152         leader = list_entry(list->next, struct perf_evsel, node);
153         evsel = list_entry(list->prev, struct perf_evsel, node);
154 
155         leader->nr_members = evsel->idx - leader->idx + 1;
156 
157         __evlist__for_each(list, evsel) {
158                 evsel->leader = leader;
159         }
160 }
161 
162 void perf_evlist__set_leader(struct perf_evlist *evlist)
163 {
164         if (evlist->nr_entries) {
165                 evlist->nr_groups = evlist->nr_entries > 1 ? 1 : 0;
166                 __perf_evlist__set_leader(&evlist->entries);
167         }
168 }
169 
170 int perf_evlist__add_default(struct perf_evlist *evlist)
171 {
172         struct perf_event_attr attr = {
173                 .type = PERF_TYPE_HARDWARE,
174                 .config = PERF_COUNT_HW_CPU_CYCLES,
175         };
176         struct perf_evsel *evsel;
177 
178         event_attr_init(&attr);
179 
180         evsel = perf_evsel__new(&attr);
181         if (evsel == NULL)
182                 goto error;
183 
184         /* use strdup() because free(evsel) assumes name is allocated */
185         evsel->name = strdup("cycles");
186         if (!evsel->name)
187                 goto error_free;
188 
189         perf_evlist__add(evlist, evsel);
190         return 0;
191 error_free:
192         perf_evsel__delete(evsel);
193 error:
194         return -ENOMEM;
195 }
196 
197 static int perf_evlist__add_attrs(struct perf_evlist *evlist,
198                                   struct perf_event_attr *attrs, size_t nr_attrs)
199 {
200         struct perf_evsel *evsel, *n;
201         LIST_HEAD(head);
202         size_t i;
203 
204         for (i = 0; i < nr_attrs; i++) {
205                 evsel = perf_evsel__new_idx(attrs + i, evlist->nr_entries + i);
206                 if (evsel == NULL)
207                         goto out_delete_partial_list;
208                 list_add_tail(&evsel->node, &head);
209         }
210 
211         perf_evlist__splice_list_tail(evlist, &head, nr_attrs);
212 
213         return 0;
214 
215 out_delete_partial_list:
216         __evlist__for_each_safe(&head, n, evsel)
217                 perf_evsel__delete(evsel);
218         return -1;
219 }
220 
221 int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
222                                      struct perf_event_attr *attrs, size_t nr_attrs)
223 {
224         size_t i;
225 
226         for (i = 0; i < nr_attrs; i++)
227                 event_attr_init(attrs + i);
228 
229         return perf_evlist__add_attrs(evlist, attrs, nr_attrs);
230 }
231 
232 struct perf_evsel *
233 perf_evlist__find_tracepoint_by_id(struct perf_evlist *evlist, int id)
234 {
235         struct perf_evsel *evsel;
236 
237         evlist__for_each(evlist, evsel) {
238                 if (evsel->attr.type   == PERF_TYPE_TRACEPOINT &&
239                     (int)evsel->attr.config == id)
240                         return evsel;
241         }
242 
243         return NULL;
244 }
245 
246 struct perf_evsel *
247 perf_evlist__find_tracepoint_by_name(struct perf_evlist *evlist,
248                                      const char *name)
249 {
250         struct perf_evsel *evsel;
251 
252         evlist__for_each(evlist, evsel) {
253                 if ((evsel->attr.type == PERF_TYPE_TRACEPOINT) &&
254                     (strcmp(evsel->name, name) == 0))
255                         return evsel;
256         }
257 
258         return NULL;
259 }
260 
261 int perf_evlist__add_newtp(struct perf_evlist *evlist,
262                            const char *sys, const char *name, void *handler)
263 {
264         struct perf_evsel *evsel = perf_evsel__newtp(sys, name);
265 
266         if (evsel == NULL)
267                 return -1;
268 
269         evsel->handler = handler;
270         perf_evlist__add(evlist, evsel);
271         return 0;
272 }
273 
274 static int perf_evlist__nr_threads(struct perf_evlist *evlist,
275                                    struct perf_evsel *evsel)
276 {
277         if (evsel->system_wide)
278                 return 1;
279         else
280                 return thread_map__nr(evlist->threads);
281 }
282 
283 void perf_evlist__disable(struct perf_evlist *evlist)
284 {
285         int cpu, thread;
286         struct perf_evsel *pos;
287         int nr_cpus = cpu_map__nr(evlist->cpus);
288         int nr_threads;
289 
290         for (cpu = 0; cpu < nr_cpus; cpu++) {
291                 evlist__for_each(evlist, pos) {
292                         if (!perf_evsel__is_group_leader(pos) || !pos->fd)
293                                 continue;
294                         nr_threads = perf_evlist__nr_threads(evlist, pos);
295                         for (thread = 0; thread < nr_threads; thread++)
296                                 ioctl(FD(pos, cpu, thread),
297                                       PERF_EVENT_IOC_DISABLE, 0);
298                 }
299         }
300 
301         evlist->enabled = false;
302 }
303 
304 void perf_evlist__enable(struct perf_evlist *evlist)
305 {
306         int cpu, thread;
307         struct perf_evsel *pos;
308         int nr_cpus = cpu_map__nr(evlist->cpus);
309         int nr_threads;
310 
311         for (cpu = 0; cpu < nr_cpus; cpu++) {
312                 evlist__for_each(evlist, pos) {
313                         if (!perf_evsel__is_group_leader(pos) || !pos->fd)
314                                 continue;
315                         nr_threads = perf_evlist__nr_threads(evlist, pos);
316                         for (thread = 0; thread < nr_threads; thread++)
317                                 ioctl(FD(pos, cpu, thread),
318                                       PERF_EVENT_IOC_ENABLE, 0);
319                 }
320         }
321 
322         evlist->enabled = true;
323 }
324 
325 void perf_evlist__toggle_enable(struct perf_evlist *evlist)
326 {
327         (evlist->enabled ? perf_evlist__disable : perf_evlist__enable)(evlist);
328 }
329 
330 int perf_evlist__disable_event(struct perf_evlist *evlist,
331                                struct perf_evsel *evsel)
332 {
333         int cpu, thread, err;
334         int nr_cpus = cpu_map__nr(evlist->cpus);
335         int nr_threads = perf_evlist__nr_threads(evlist, evsel);
336 
337         if (!evsel->fd)
338                 return 0;
339 
340         for (cpu = 0; cpu < nr_cpus; cpu++) {
341                 for (thread = 0; thread < nr_threads; thread++) {
342                         err = ioctl(FD(evsel, cpu, thread),
343                                     PERF_EVENT_IOC_DISABLE, 0);
344                         if (err)
345                                 return err;
346                 }
347         }
348         return 0;
349 }
350 
351 int perf_evlist__enable_event(struct perf_evlist *evlist,
352                               struct perf_evsel *evsel)
353 {
354         int cpu, thread, err;
355         int nr_cpus = cpu_map__nr(evlist->cpus);
356         int nr_threads = perf_evlist__nr_threads(evlist, evsel);
357 
358         if (!evsel->fd)
359                 return -EINVAL;
360 
361         for (cpu = 0; cpu < nr_cpus; cpu++) {
362                 for (thread = 0; thread < nr_threads; thread++) {
363                         err = ioctl(FD(evsel, cpu, thread),
364                                     PERF_EVENT_IOC_ENABLE, 0);
365                         if (err)
366                                 return err;
367                 }
368         }
369         return 0;
370 }
371 
372 static int perf_evlist__enable_event_cpu(struct perf_evlist *evlist,
373                                          struct perf_evsel *evsel, int cpu)
374 {
375         int thread, err;
376         int nr_threads = perf_evlist__nr_threads(evlist, evsel);
377 
378         if (!evsel->fd)
379                 return -EINVAL;
380 
381         for (thread = 0; thread < nr_threads; thread++) {
382                 err = ioctl(FD(evsel, cpu, thread),
383                             PERF_EVENT_IOC_ENABLE, 0);
384                 if (err)
385                         return err;
386         }
387         return 0;
388 }
389 
390 static int perf_evlist__enable_event_thread(struct perf_evlist *evlist,
391                                             struct perf_evsel *evsel,
392                                             int thread)
393 {
394         int cpu, err;
395         int nr_cpus = cpu_map__nr(evlist->cpus);
396 
397         if (!evsel->fd)
398                 return -EINVAL;
399 
400         for (cpu = 0; cpu < nr_cpus; cpu++) {
401                 err = ioctl(FD(evsel, cpu, thread), PERF_EVENT_IOC_ENABLE, 0);
402                 if (err)
403                         return err;
404         }
405         return 0;
406 }
407 
408 int perf_evlist__enable_event_idx(struct perf_evlist *evlist,
409                                   struct perf_evsel *evsel, int idx)
410 {
411         bool per_cpu_mmaps = !cpu_map__empty(evlist->cpus);
412 
413         if (per_cpu_mmaps)
414                 return perf_evlist__enable_event_cpu(evlist, evsel, idx);
415         else
416                 return perf_evlist__enable_event_thread(evlist, evsel, idx);
417 }
418 
419 int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
420 {
421         int nr_cpus = cpu_map__nr(evlist->cpus);
422         int nr_threads = thread_map__nr(evlist->threads);
423         int nfds = 0;
424         struct perf_evsel *evsel;
425 
426         evlist__for_each(evlist, evsel) {
427                 if (evsel->system_wide)
428                         nfds += nr_cpus;
429                 else
430                         nfds += nr_cpus * nr_threads;
431         }
432 
433         if (fdarray__available_entries(&evlist->pollfd) < nfds &&
434             fdarray__grow(&evlist->pollfd, nfds) < 0)
435                 return -ENOMEM;
436 
437         return 0;
438 }
439 
440 static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx)
441 {
442         int pos = fdarray__add(&evlist->pollfd, fd, POLLIN | POLLERR | POLLHUP);
443         /*
444          * Save the idx so that when we filter out fds POLLHUP'ed we can
445          * close the associated evlist->mmap[] entry.
446          */
447         if (pos >= 0) {
448                 evlist->pollfd.priv[pos].idx = idx;
449 
450                 fcntl(fd, F_SETFL, O_NONBLOCK);
451         }
452 
453         return pos;
454 }
455 
456 int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
457 {
458         return __perf_evlist__add_pollfd(evlist, fd, -1);
459 }
460 
461 static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd)
462 {
463         struct perf_evlist *evlist = container_of(fda, struct perf_evlist, pollfd);
464 
465         perf_evlist__mmap_put(evlist, fda->priv[fd].idx);
466 }
467 
468 int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask)
469 {
470         return fdarray__filter(&evlist->pollfd, revents_and_mask,
471                                perf_evlist__munmap_filtered);
472 }
473 
474 int perf_evlist__poll(struct perf_evlist *evlist, int timeout)
475 {
476         return fdarray__poll(&evlist->pollfd, timeout);
477 }
478 
479 static void perf_evlist__id_hash(struct perf_evlist *evlist,
480                                  struct perf_evsel *evsel,
481                                  int cpu, int thread, u64 id)
482 {
483         int hash;
484         struct perf_sample_id *sid = SID(evsel, cpu, thread);
485 
486         sid->id = id;
487         sid->evsel = evsel;
488         hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
489         hlist_add_head(&sid->node, &evlist->heads[hash]);
490 }
491 
492 void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel,
493                          int cpu, int thread, u64 id)
494 {
495         perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
496         evsel->id[evsel->ids++] = id;
497 }
498 
499 static int perf_evlist__id_add_fd(struct perf_evlist *evlist,
500                                   struct perf_evsel *evsel,
501                                   int cpu, int thread, int fd)
502 {
503         u64 read_data[4] = { 0, };
504         int id_idx = 1; /* The first entry is the counter value */
505         u64 id;
506         int ret;
507 
508         ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
509         if (!ret)
510                 goto add;
511 
512         if (errno != ENOTTY)
513                 return -1;
514 
515         /* Legacy way to get event id.. All hail to old kernels! */
516 
517         /*
518          * This way does not work with group format read, so bail
519          * out in that case.
520          */
521         if (perf_evlist__read_format(evlist) & PERF_FORMAT_GROUP)
522                 return -1;
523 
524         if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
525             read(fd, &read_data, sizeof(read_data)) == -1)
526                 return -1;
527 
528         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
529                 ++id_idx;
530         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
531                 ++id_idx;
532 
533         id = read_data[id_idx];
534 
535  add:
536         perf_evlist__id_add(evlist, evsel, cpu, thread, id);
537         return 0;
538 }
539 
540 static void perf_evlist__set_sid_idx(struct perf_evlist *evlist,
541                                      struct perf_evsel *evsel, int idx, int cpu,
542                                      int thread)
543 {
544         struct perf_sample_id *sid = SID(evsel, cpu, thread);
545         sid->idx = idx;
546         if (evlist->cpus && cpu >= 0)
547                 sid->cpu = evlist->cpus->map[cpu];
548         else
549                 sid->cpu = -1;
550         if (!evsel->system_wide && evlist->threads && thread >= 0)
551                 sid->tid = thread_map__pid(evlist->threads, thread);
552         else
553                 sid->tid = -1;
554 }
555 
556 struct perf_sample_id *perf_evlist__id2sid(struct perf_evlist *evlist, u64 id)
557 {
558         struct hlist_head *head;
559         struct perf_sample_id *sid;
560         int hash;
561 
562         hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
563         head = &evlist->heads[hash];
564 
565         hlist_for_each_entry(sid, head, node)
566                 if (sid->id == id)
567                         return sid;
568 
569         return NULL;
570 }
571 
572 struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
573 {
574         struct perf_sample_id *sid;
575 
576         if (evlist->nr_entries == 1)
577                 return perf_evlist__first(evlist);
578 
579         sid = perf_evlist__id2sid(evlist, id);
580         if (sid)
581                 return sid->evsel;
582 
583         if (!perf_evlist__sample_id_all(evlist))
584                 return perf_evlist__first(evlist);
585 
586         return NULL;
587 }
588 
589 static int perf_evlist__event2id(struct perf_evlist *evlist,
590                                  union perf_event *event, u64 *id)
591 {
592         const u64 *array = event->sample.array;
593         ssize_t n;
594 
595         n = (event->header.size - sizeof(event->header)) >> 3;
596 
597         if (event->header.type == PERF_RECORD_SAMPLE) {
598                 if (evlist->id_pos >= n)
599                         return -1;
600                 *id = array[evlist->id_pos];
601         } else {
602                 if (evlist->is_pos > n)
603                         return -1;
604                 n -= evlist->is_pos;
605                 *id = array[n];
606         }
607         return 0;
608 }
609 
610 static struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist,
611                                                    union perf_event *event)
612 {
613         struct perf_evsel *first = perf_evlist__first(evlist);
614         struct hlist_head *head;
615         struct perf_sample_id *sid;
616         int hash;
617         u64 id;
618 
619         if (evlist->nr_entries == 1)
620                 return first;
621 
622         if (!first->attr.sample_id_all &&
623             event->header.type != PERF_RECORD_SAMPLE)
624                 return first;
625 
626         if (perf_evlist__event2id(evlist, event, &id))
627                 return NULL;
628 
629         /* Synthesized events have an id of zero */
630         if (!id)
631                 return first;
632 
633         hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
634         head = &evlist->heads[hash];
635 
636         hlist_for_each_entry(sid, head, node) {
637                 if (sid->id == id)
638                         return sid->evsel;
639         }
640         return NULL;
641 }
642 
643 union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
644 {
645         struct perf_mmap *md = &evlist->mmap[idx];
646         u64 head;
647         u64 old = md->prev;
648         unsigned char *data = md->base + page_size;
649         union perf_event *event = NULL;
650 
651         /*
652          * Check if event was unmapped due to a POLLHUP/POLLERR.
653          */
654         if (!atomic_read(&md->refcnt))
655                 return NULL;
656 
657         head = perf_mmap__read_head(md);
658         if (evlist->overwrite) {
659                 /*
660                  * If we're further behind than half the buffer, there's a chance
661                  * the writer will bite our tail and mess up the samples under us.
662                  *
663                  * If we somehow ended up ahead of the head, we got messed up.
664                  *
665                  * In either case, truncate and restart at head.
666                  */
667                 int diff = head - old;
668                 if (diff > md->mask / 2 || diff < 0) {
669                         fprintf(stderr, "WARNING: failed to keep up with mmap data.\n");
670 
671                         /*
672                          * head points to a known good entry, start there.
673                          */
674                         old = head;
675                 }
676         }
677 
678         if (old != head) {
679                 size_t size;
680 
681                 event = (union perf_event *)&data[old & md->mask];
682                 size = event->header.size;
683 
684                 /*
685                  * Event straddles the mmap boundary -- header should always
686                  * be inside due to u64 alignment of output.
687                  */
688                 if ((old & md->mask) + size != ((old + size) & md->mask)) {
689                         unsigned int offset = old;
690                         unsigned int len = min(sizeof(*event), size), cpy;
691                         void *dst = md->event_copy;
692 
693                         do {
694                                 cpy = min(md->mask + 1 - (offset & md->mask), len);
695                                 memcpy(dst, &data[offset & md->mask], cpy);
696                                 offset += cpy;
697                                 dst += cpy;
698                                 len -= cpy;
699                         } while (len);
700 
701                         event = (union perf_event *) md->event_copy;
702                 }
703 
704                 old += size;
705         }
706 
707         md->prev = old;
708 
709         return event;
710 }
711 
712 static bool perf_mmap__empty(struct perf_mmap *md)
713 {
714         return perf_mmap__read_head(md) == md->prev && !md->auxtrace_mmap.base;
715 }
716 
717 static void perf_evlist__mmap_get(struct perf_evlist *evlist, int idx)
718 {
719         atomic_inc(&evlist->mmap[idx].refcnt);
720 }
721 
722 static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx)
723 {
724         BUG_ON(atomic_read(&evlist->mmap[idx].refcnt) == 0);
725 
726         if (atomic_dec_and_test(&evlist->mmap[idx].refcnt))
727                 __perf_evlist__munmap(evlist, idx);
728 }
729 
730 void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx)
731 {
732         struct perf_mmap *md = &evlist->mmap[idx];
733 
734         if (!evlist->overwrite) {
735                 u64 old = md->prev;
736 
737                 perf_mmap__write_tail(md, old);
738         }
739 
740         if (atomic_read(&md->refcnt) == 1 && perf_mmap__empty(md))
741                 perf_evlist__mmap_put(evlist, idx);
742 }
743 
744 int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused,
745                                struct auxtrace_mmap_params *mp __maybe_unused,
746                                void *userpg __maybe_unused,
747                                int fd __maybe_unused)
748 {
749         return 0;
750 }
751 
752 void __weak auxtrace_mmap__munmap(struct auxtrace_mmap *mm __maybe_unused)
753 {
754 }
755 
756 void __weak auxtrace_mmap_params__init(
757                         struct auxtrace_mmap_params *mp __maybe_unused,
758                         off_t auxtrace_offset __maybe_unused,
759                         unsigned int auxtrace_pages __maybe_unused,
760                         bool auxtrace_overwrite __maybe_unused)
761 {
762 }
763 
764 void __weak auxtrace_mmap_params__set_idx(
765                         struct auxtrace_mmap_params *mp __maybe_unused,
766                         struct perf_evlist *evlist __maybe_unused,
767                         int idx __maybe_unused,
768                         bool per_cpu __maybe_unused)
769 {
770 }
771 
772 static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx)
773 {
774         if (evlist->mmap[idx].base != NULL) {
775                 munmap(evlist->mmap[idx].base, evlist->mmap_len);
776                 evlist->mmap[idx].base = NULL;
777                 atomic_set(&evlist->mmap[idx].refcnt, 0);
778         }
779         auxtrace_mmap__munmap(&evlist->mmap[idx].auxtrace_mmap);
780 }
781 
782 void perf_evlist__munmap(struct perf_evlist *evlist)
783 {
784         int i;
785 
786         if (evlist->mmap == NULL)
787                 return;
788 
789         for (i = 0; i < evlist->nr_mmaps; i++)
790                 __perf_evlist__munmap(evlist, i);
791 
792         zfree(&evlist->mmap);
793 }
794 
795 static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
796 {
797         evlist->nr_mmaps = cpu_map__nr(evlist->cpus);
798         if (cpu_map__empty(evlist->cpus))
799                 evlist->nr_mmaps = thread_map__nr(evlist->threads);
800         evlist->mmap = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
801         return evlist->mmap != NULL ? 0 : -ENOMEM;
802 }
803 
804 struct mmap_params {
805         int prot;
806         int mask;
807         struct auxtrace_mmap_params auxtrace_mp;
808 };
809 
810 static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
811                                struct mmap_params *mp, int fd)
812 {
813         /*
814          * The last one will be done at perf_evlist__mmap_consume(), so that we
815          * make sure we don't prevent tools from consuming every last event in
816          * the ring buffer.
817          *
818          * I.e. we can get the POLLHUP meaning that the fd doesn't exist
819          * anymore, but the last events for it are still in the ring buffer,
820          * waiting to be consumed.
821          *
822          * Tools can chose to ignore this at their own discretion, but the
823          * evlist layer can't just drop it when filtering events in
824          * perf_evlist__filter_pollfd().
825          */
826         atomic_set(&evlist->mmap[idx].refcnt, 2);
827         evlist->mmap[idx].prev = 0;
828         evlist->mmap[idx].mask = mp->mask;
829         evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, mp->prot,
830                                       MAP_SHARED, fd, 0);
831         if (evlist->mmap[idx].base == MAP_FAILED) {
832                 pr_debug2("failed to mmap perf event ring buffer, error %d\n",
833                           errno);
834                 evlist->mmap[idx].base = NULL;
835                 return -1;
836         }
837 
838         if (auxtrace_mmap__mmap(&evlist->mmap[idx].auxtrace_mmap,
839                                 &mp->auxtrace_mp, evlist->mmap[idx].base, fd))
840                 return -1;
841 
842         return 0;
843 }
844 
845 static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
846                                        struct mmap_params *mp, int cpu,
847                                        int thread, int *output)
848 {
849         struct perf_evsel *evsel;
850 
851         evlist__for_each(evlist, evsel) {
852                 int fd;
853 
854                 if (evsel->system_wide && thread)
855                         continue;
856 
857                 fd = FD(evsel, cpu, thread);
858 
859                 if (*output == -1) {
860                         *output = fd;
861                         if (__perf_evlist__mmap(evlist, idx, mp, *output) < 0)
862                                 return -1;
863                 } else {
864                         if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
865                                 return -1;
866 
867                         perf_evlist__mmap_get(evlist, idx);
868                 }
869 
870                 /*
871                  * The system_wide flag causes a selected event to be opened
872                  * always without a pid.  Consequently it will never get a
873                  * POLLHUP, but it is used for tracking in combination with
874                  * other events, so it should not need to be polled anyway.
875                  * Therefore don't add it for polling.
876                  */
877                 if (!evsel->system_wide &&
878                     __perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
879                         perf_evlist__mmap_put(evlist, idx);
880                         return -1;
881                 }
882 
883                 if (evsel->attr.read_format & PERF_FORMAT_ID) {
884                         if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
885                                                    fd) < 0)
886                                 return -1;
887                         perf_evlist__set_sid_idx(evlist, evsel, idx, cpu,
888                                                  thread);
889                 }
890         }
891 
892         return 0;
893 }
894 
895 static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist,
896                                      struct mmap_params *mp)
897 {
898         int cpu, thread;
899         int nr_cpus = cpu_map__nr(evlist->cpus);
900         int nr_threads = thread_map__nr(evlist->threads);
901 
902         pr_debug2("perf event ring buffer mmapped per cpu\n");
903         for (cpu = 0; cpu < nr_cpus; cpu++) {
904                 int output = -1;
905 
906                 auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist, cpu,
907                                               true);
908 
909                 for (thread = 0; thread < nr_threads; thread++) {
910                         if (perf_evlist__mmap_per_evsel(evlist, cpu, mp, cpu,
911                                                         thread, &output))
912                                 goto out_unmap;
913                 }
914         }
915 
916         return 0;
917 
918 out_unmap:
919         for (cpu = 0; cpu < nr_cpus; cpu++)
920                 __perf_evlist__munmap(evlist, cpu);
921         return -1;
922 }
923 
924 static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist,
925                                         struct mmap_params *mp)
926 {
927         int thread;
928         int nr_threads = thread_map__nr(evlist->threads);
929 
930         pr_debug2("perf event ring buffer mmapped per thread\n");
931         for (thread = 0; thread < nr_threads; thread++) {
932                 int output = -1;
933 
934                 auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist, thread,
935                                               false);
936 
937                 if (perf_evlist__mmap_per_evsel(evlist, thread, mp, 0, thread,
938                                                 &output))
939                         goto out_unmap;
940         }
941 
942         return 0;
943 
944 out_unmap:
945         for (thread = 0; thread < nr_threads; thread++)
946                 __perf_evlist__munmap(evlist, thread);
947         return -1;
948 }
949 
950 static size_t perf_evlist__mmap_size(unsigned long pages)
951 {
952         if (pages == UINT_MAX) {
953                 int max;
954 
955                 if (sysctl__read_int("kernel/perf_event_mlock_kb", &max) < 0) {
956                         /*
957                          * Pick a once upon a time good value, i.e. things look
958                          * strange since we can't read a sysctl value, but lets not
959                          * die yet...
960                          */
961                         max = 512;
962                 } else {
963                         max -= (page_size / 1024);
964                 }
965 
966                 pages = (max * 1024) / page_size;
967                 if (!is_power_of_2(pages))
968                         pages = rounddown_pow_of_two(pages);
969         } else if (!is_power_of_2(pages))
970                 return 0;
971 
972         return (pages + 1) * page_size;
973 }
974 
975 static long parse_pages_arg(const char *str, unsigned long min,
976                             unsigned long max)
977 {
978         unsigned long pages, val;
979         static struct parse_tag tags[] = {
980                 { .tag  = 'B', .mult = 1       },
981                 { .tag  = 'K', .mult = 1 << 10 },
982                 { .tag  = 'M', .mult = 1 << 20 },
983                 { .tag  = 'G', .mult = 1 << 30 },
984                 { .tag  = 0 },
985         };
986 
987         if (str == NULL)
988                 return -EINVAL;
989 
990         val = parse_tag_value(str, tags);
991         if (val != (unsigned long) -1) {
992                 /* we got file size value */
993                 pages = PERF_ALIGN(val, page_size) / page_size;
994         } else {
995                 /* we got pages count value */
996                 char *eptr;
997                 pages = strtoul(str, &eptr, 10);
998                 if (*eptr != '\0')
999                         return -EINVAL;
1000         }
1001 
1002         if (pages == 0 && min == 0) {
1003                 /* leave number of pages at 0 */
1004         } else if (!is_power_of_2(pages)) {
1005                 /* round pages up to next power of 2 */
1006                 pages = roundup_pow_of_two(pages);
1007                 if (!pages)
1008                         return -EINVAL;
1009                 pr_info("rounding mmap pages size to %lu bytes (%lu pages)\n",
1010                         pages * page_size, pages);
1011         }
1012 
1013         if (pages > max)
1014                 return -EINVAL;
1015 
1016         return pages;
1017 }
1018 
1019 int __perf_evlist__parse_mmap_pages(unsigned int *mmap_pages, const char *str)
1020 {
1021         unsigned long max = UINT_MAX;
1022         long pages;
1023 
1024         if (max > SIZE_MAX / page_size)
1025                 max = SIZE_MAX / page_size;
1026 
1027         pages = parse_pages_arg(str, 1, max);
1028         if (pages < 0) {
1029                 pr_err("Invalid argument for --mmap_pages/-m\n");
1030                 return -1;
1031         }
1032 
1033         *mmap_pages = pages;
1034         return 0;
1035 }
1036 
1037 int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
1038                                   int unset __maybe_unused)
1039 {
1040         return __perf_evlist__parse_mmap_pages(opt->value, str);
1041 }
1042 
1043 /**
1044  * perf_evlist__mmap_ex - Create mmaps to receive events.
1045  * @evlist: list of events
1046  * @pages: map length in pages
1047  * @overwrite: overwrite older events?
1048  * @auxtrace_pages - auxtrace map length in pages
1049  * @auxtrace_overwrite - overwrite older auxtrace data?
1050  *
1051  * If @overwrite is %false the user needs to signal event consumption using
1052  * perf_mmap__write_tail().  Using perf_evlist__mmap_read() does this
1053  * automatically.
1054  *
1055  * Similarly, if @auxtrace_overwrite is %false the user needs to signal data
1056  * consumption using auxtrace_mmap__write_tail().
1057  *
1058  * Return: %0 on success, negative error code otherwise.
1059  */
1060 int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
1061                          bool overwrite, unsigned int auxtrace_pages,
1062                          bool auxtrace_overwrite)
1063 {
1064         struct perf_evsel *evsel;
1065         const struct cpu_map *cpus = evlist->cpus;
1066         const struct thread_map *threads = evlist->threads;
1067         struct mmap_params mp = {
1068                 .prot = PROT_READ | (overwrite ? 0 : PROT_WRITE),
1069         };
1070 
1071         if (evlist->mmap == NULL && perf_evlist__alloc_mmap(evlist) < 0)
1072                 return -ENOMEM;
1073 
1074         if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
1075                 return -ENOMEM;
1076 
1077         evlist->overwrite = overwrite;
1078         evlist->mmap_len = perf_evlist__mmap_size(pages);
1079         pr_debug("mmap size %zuB\n", evlist->mmap_len);
1080         mp.mask = evlist->mmap_len - page_size - 1;
1081 
1082         auxtrace_mmap_params__init(&mp.auxtrace_mp, evlist->mmap_len,
1083                                    auxtrace_pages, auxtrace_overwrite);
1084 
1085         evlist__for_each(evlist, evsel) {
1086                 if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
1087                     evsel->sample_id == NULL &&
1088                     perf_evsel__alloc_id(evsel, cpu_map__nr(cpus), threads->nr) < 0)
1089                         return -ENOMEM;
1090         }
1091 
1092         if (cpu_map__empty(cpus))
1093                 return perf_evlist__mmap_per_thread(evlist, &mp);
1094 
1095         return perf_evlist__mmap_per_cpu(evlist, &mp);
1096 }
1097 
1098 int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
1099                       bool overwrite)
1100 {
1101         return perf_evlist__mmap_ex(evlist, pages, overwrite, 0, false);
1102 }
1103 
1104 static int perf_evlist__propagate_maps(struct perf_evlist *evlist,
1105                                        struct target *target)
1106 {
1107         struct perf_evsel *evsel;
1108 
1109         evlist__for_each(evlist, evsel) {
1110                 /*
1111                  * We already have cpus for evsel (via PMU sysfs) so
1112                  * keep it, if there's no target cpu list defined.
1113                  */
1114                 if (evsel->cpus && target->cpu_list)
1115                         cpu_map__put(evsel->cpus);
1116 
1117                 if (!evsel->cpus || target->cpu_list)
1118                         evsel->cpus = cpu_map__get(evlist->cpus);
1119 
1120                 evsel->threads = thread_map__get(evlist->threads);
1121 
1122                 if (!evsel->cpus || !evsel->threads)
1123                         return -ENOMEM;
1124         }
1125 
1126         return 0;
1127 }
1128 
1129 int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
1130 {
1131         evlist->threads = thread_map__new_str(target->pid, target->tid,
1132                                               target->uid);
1133 
1134         if (evlist->threads == NULL)
1135                 return -1;
1136 
1137         if (target__uses_dummy_map(target))
1138                 evlist->cpus = cpu_map__dummy_new();
1139         else
1140                 evlist->cpus = cpu_map__new(target->cpu_list);
1141 
1142         if (evlist->cpus == NULL)
1143                 goto out_delete_threads;
1144 
1145         return perf_evlist__propagate_maps(evlist, target);
1146 
1147 out_delete_threads:
1148         thread_map__put(evlist->threads);
1149         evlist->threads = NULL;
1150         return -1;
1151 }
1152 
1153 int perf_evlist__apply_filters(struct perf_evlist *evlist, struct perf_evsel **err_evsel)
1154 {
1155         struct perf_evsel *evsel;
1156         int err = 0;
1157         const int ncpus = cpu_map__nr(evlist->cpus),
1158                   nthreads = thread_map__nr(evlist->threads);
1159 
1160         evlist__for_each(evlist, evsel) {
1161                 if (evsel->filter == NULL)
1162                         continue;
1163 
1164                 err = perf_evsel__set_filter(evsel, ncpus, nthreads, evsel->filter);
1165                 if (err) {
1166                         *err_evsel = evsel;
1167                         break;
1168                 }
1169         }
1170 
1171         return err;
1172 }
1173 
1174 int perf_evlist__set_filter(struct perf_evlist *evlist, const char *filter)
1175 {
1176         struct perf_evsel *evsel;
1177         int err = 0;
1178         const int ncpus = cpu_map__nr(evlist->cpus),
1179                   nthreads = thread_map__nr(evlist->threads);
1180 
1181         evlist__for_each(evlist, evsel) {
1182                 err = perf_evsel__set_filter(evsel, ncpus, nthreads, filter);
1183                 if (err)
1184                         break;
1185         }
1186 
1187         return err;
1188 }
1189 
1190 int perf_evlist__set_filter_pids(struct perf_evlist *evlist, size_t npids, pid_t *pids)
1191 {
1192         char *filter;
1193         int ret = -1;
1194         size_t i;
1195 
1196         for (i = 0; i < npids; ++i) {
1197                 if (i == 0) {
1198                         if (asprintf(&filter, "common_pid != %d", pids[i]) < 0)
1199                                 return -1;
1200                 } else {
1201                         char *tmp;
1202 
1203                         if (asprintf(&tmp, "%s && common_pid != %d", filter, pids[i]) < 0)
1204                                 goto out_free;
1205 
1206                         free(filter);
1207                         filter = tmp;
1208                 }
1209         }
1210 
1211         ret = perf_evlist__set_filter(evlist, filter);
1212 out_free:
1213         free(filter);
1214         return ret;
1215 }
1216 
1217 int perf_evlist__set_filter_pid(struct perf_evlist *evlist, pid_t pid)
1218 {
1219         return perf_evlist__set_filter_pids(evlist, 1, &pid);
1220 }
1221 
1222 bool perf_evlist__valid_sample_type(struct perf_evlist *evlist)
1223 {
1224         struct perf_evsel *pos;
1225 
1226         if (evlist->nr_entries == 1)
1227                 return true;
1228 
1229         if (evlist->id_pos < 0 || evlist->is_pos < 0)
1230                 return false;
1231 
1232         evlist__for_each(evlist, pos) {
1233                 if (pos->id_pos != evlist->id_pos ||
1234                     pos->is_pos != evlist->is_pos)
1235                         return false;
1236         }
1237 
1238         return true;
1239 }
1240 
1241 u64 __perf_evlist__combined_sample_type(struct perf_evlist *evlist)
1242 {
1243         struct perf_evsel *evsel;
1244 
1245         if (evlist->combined_sample_type)
1246                 return evlist->combined_sample_type;
1247 
1248         evlist__for_each(evlist, evsel)
1249                 evlist->combined_sample_type |= evsel->attr.sample_type;
1250 
1251         return evlist->combined_sample_type;
1252 }
1253 
1254 u64 perf_evlist__combined_sample_type(struct perf_evlist *evlist)
1255 {
1256         evlist->combined_sample_type = 0;
1257         return __perf_evlist__combined_sample_type(evlist);
1258 }
1259 
1260 bool perf_evlist__valid_read_format(struct perf_evlist *evlist)
1261 {
1262         struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;
1263         u64 read_format = first->attr.read_format;
1264         u64 sample_type = first->attr.sample_type;
1265 
1266         evlist__for_each(evlist, pos) {
1267                 if (read_format != pos->attr.read_format)
1268                         return false;
1269         }
1270 
1271         /* PERF_SAMPLE_READ imples PERF_FORMAT_ID. */
1272         if ((sample_type & PERF_SAMPLE_READ) &&
1273             !(read_format & PERF_FORMAT_ID)) {
1274                 return false;
1275         }
1276 
1277         return true;
1278 }
1279 
1280 u64 perf_evlist__read_format(struct perf_evlist *evlist)
1281 {
1282         struct perf_evsel *first = perf_evlist__first(evlist);
1283         return first->attr.read_format;
1284 }
1285 
1286 u16 perf_evlist__id_hdr_size(struct perf_evlist *evlist)
1287 {
1288         struct perf_evsel *first = perf_evlist__first(evlist);
1289         struct perf_sample *data;
1290         u64 sample_type;
1291         u16 size = 0;
1292 
1293         if (!first->attr.sample_id_all)
1294                 goto out;
1295 
1296         sample_type = first->attr.sample_type;
1297 
1298         if (sample_type & PERF_SAMPLE_TID)
1299                 size += sizeof(data->tid) * 2;
1300 
1301        if (sample_type & PERF_SAMPLE_TIME)
1302                 size += sizeof(data->time);
1303 
1304         if (sample_type & PERF_SAMPLE_ID)
1305                 size += sizeof(data->id);
1306 
1307         if (sample_type & PERF_SAMPLE_STREAM_ID)
1308                 size += sizeof(data->stream_id);
1309 
1310         if (sample_type & PERF_SAMPLE_CPU)
1311                 size += sizeof(data->cpu) * 2;
1312 
1313         if (sample_type & PERF_SAMPLE_IDENTIFIER)
1314                 size += sizeof(data->id);
1315 out:
1316         return size;
1317 }
1318 
1319 bool perf_evlist__valid_sample_id_all(struct perf_evlist *evlist)
1320 {
1321         struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;
1322 
1323         evlist__for_each_continue(evlist, pos) {
1324                 if (first->attr.sample_id_all != pos->attr.sample_id_all)
1325                         return false;
1326         }
1327 
1328         return true;
1329 }
1330 
1331 bool perf_evlist__sample_id_all(struct perf_evlist *evlist)
1332 {
1333         struct perf_evsel *first = perf_evlist__first(evlist);
1334         return first->attr.sample_id_all;
1335 }
1336 
1337 void perf_evlist__set_selected(struct perf_evlist *evlist,
1338                                struct perf_evsel *evsel)
1339 {
1340         evlist->selected = evsel;
1341 }
1342 
1343 void perf_evlist__close(struct perf_evlist *evlist)
1344 {
1345         struct perf_evsel *evsel;
1346         int ncpus = cpu_map__nr(evlist->cpus);
1347         int nthreads = thread_map__nr(evlist->threads);
1348         int n;
1349 
1350         evlist__for_each_reverse(evlist, evsel) {
1351                 n = evsel->cpus ? evsel->cpus->nr : ncpus;
1352                 perf_evsel__close(evsel, n, nthreads);
1353         }
1354 }
1355 
1356 static int perf_evlist__create_syswide_maps(struct perf_evlist *evlist)
1357 {
1358         int err = -ENOMEM;
1359 
1360         /*
1361          * Try reading /sys/devices/system/cpu/online to get
1362          * an all cpus map.
1363          *
1364          * FIXME: -ENOMEM is the best we can do here, the cpu_map
1365          * code needs an overhaul to properly forward the
1366          * error, and we may not want to do that fallback to a
1367          * default cpu identity map :-\
1368          */
1369         evlist->cpus = cpu_map__new(NULL);
1370         if (evlist->cpus == NULL)
1371                 goto out;
1372 
1373         evlist->threads = thread_map__new_dummy();
1374         if (evlist->threads == NULL)
1375                 goto out_free_cpus;
1376 
1377         err = 0;
1378 out:
1379         return err;
1380 out_free_cpus:
1381         cpu_map__put(evlist->cpus);
1382         evlist->cpus = NULL;
1383         goto out;
1384 }
1385 
1386 int perf_evlist__open(struct perf_evlist *evlist)
1387 {
1388         struct perf_evsel *evsel;
1389         int err;
1390 
1391         /*
1392          * Default: one fd per CPU, all threads, aka systemwide
1393          * as sys_perf_event_open(cpu = -1, thread = -1) is EINVAL
1394          */
1395         if (evlist->threads == NULL && evlist->cpus == NULL) {
1396                 err = perf_evlist__create_syswide_maps(evlist);
1397                 if (err < 0)
1398                         goto out_err;
1399         }
1400 
1401         perf_evlist__update_id_pos(evlist);
1402 
1403         evlist__for_each(evlist, evsel) {
1404                 err = perf_evsel__open(evsel, evlist->cpus, evlist->threads);
1405                 if (err < 0)
1406                         goto out_err;
1407         }
1408 
1409         return 0;
1410 out_err:
1411         perf_evlist__close(evlist);
1412         errno = -err;
1413         return err;
1414 }
1415 
1416 int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct target *target,
1417                                   const char *argv[], bool pipe_output,
1418                                   void (*exec_error)(int signo, siginfo_t *info, void *ucontext))
1419 {
1420         int child_ready_pipe[2], go_pipe[2];
1421         char bf;
1422 
1423         if (pipe(child_ready_pipe) < 0) {
1424                 perror("failed to create 'ready' pipe");
1425                 return -1;
1426         }
1427 
1428         if (pipe(go_pipe) < 0) {
1429                 perror("failed to create 'go' pipe");
1430                 goto out_close_ready_pipe;
1431         }
1432 
1433         evlist->workload.pid = fork();
1434         if (evlist->workload.pid < 0) {
1435                 perror("failed to fork");
1436                 goto out_close_pipes;
1437         }
1438 
1439         if (!evlist->workload.pid) {
1440                 int ret;
1441 
1442                 if (pipe_output)
1443                         dup2(2, 1);
1444 
1445                 signal(SIGTERM, SIG_DFL);
1446 
1447                 close(child_ready_pipe[0]);
1448                 close(go_pipe[1]);
1449                 fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
1450 
1451                 /*
1452                  * Tell the parent we're ready to go
1453                  */
1454                 close(child_ready_pipe[1]);
1455 
1456                 /*
1457                  * Wait until the parent tells us to go.
1458                  */
1459                 ret = read(go_pipe[0], &bf, 1);
1460                 /*
1461                  * The parent will ask for the execvp() to be performed by
1462                  * writing exactly one byte, in workload.cork_fd, usually via
1463                  * perf_evlist__start_workload().
1464                  *
1465                  * For cancelling the workload without actually running it,
1466                  * the parent will just close workload.cork_fd, without writing
1467                  * anything, i.e. read will return zero and we just exit()
1468                  * here.
1469                  */
1470                 if (ret != 1) {
1471                         if (ret == -1)
1472                                 perror("unable to read pipe");
1473                         exit(ret);
1474                 }
1475 
1476                 execvp(argv[0], (char **)argv);
1477 
1478                 if (exec_error) {
1479                         union sigval val;
1480 
1481                         val.sival_int = errno;
1482                         if (sigqueue(getppid(), SIGUSR1, val))
1483                                 perror(argv[0]);
1484                 } else
1485                         perror(argv[0]);
1486                 exit(-1);
1487         }
1488 
1489         if (exec_error) {
1490                 struct sigaction act = {
1491                         .sa_flags     = SA_SIGINFO,
1492                         .sa_sigaction = exec_error,
1493                 };
1494                 sigaction(SIGUSR1, &act, NULL);
1495         }
1496 
1497         if (target__none(target)) {
1498                 if (evlist->threads == NULL) {
1499                         fprintf(stderr, "FATAL: evlist->threads need to be set at this point (%s:%d).\n",
1500                                 __func__, __LINE__);
1501                         goto out_close_pipes;
1502                 }
1503                 thread_map__set_pid(evlist->threads, 0, evlist->workload.pid);
1504         }
1505 
1506         close(child_ready_pipe[1]);
1507         close(go_pipe[0]);
1508         /*
1509          * wait for child to settle
1510          */
1511         if (read(child_ready_pipe[0], &bf, 1) == -1) {
1512                 perror("unable to read pipe");
1513                 goto out_close_pipes;
1514         }
1515 
1516         fcntl(go_pipe[1], F_SETFD, FD_CLOEXEC);
1517         evlist->workload.cork_fd = go_pipe[1];
1518         close(child_ready_pipe[0]);
1519         return 0;
1520 
1521 out_close_pipes:
1522         close(go_pipe[0]);
1523         close(go_pipe[1]);
1524 out_close_ready_pipe:
1525         close(child_ready_pipe[0]);
1526         close(child_ready_pipe[1]);
1527         return -1;
1528 }
1529 
1530 int perf_evlist__start_workload(struct perf_evlist *evlist)
1531 {
1532         if (evlist->workload.cork_fd > 0) {
1533                 char bf = 0;
1534                 int ret;
1535                 /*
1536                  * Remove the cork, let it rip!
1537                  */
1538                 ret = write(evlist->workload.cork_fd, &bf, 1);
1539                 if (ret < 0)
1540                         perror("enable to write to pipe");
1541 
1542                 close(evlist->workload.cork_fd);
1543                 return ret;
1544         }
1545 
1546         return 0;
1547 }
1548 
1549 int perf_evlist__parse_sample(struct perf_evlist *evlist, union perf_event *event,
1550                               struct perf_sample *sample)
1551 {
1552         struct perf_evsel *evsel = perf_evlist__event2evsel(evlist, event);
1553 
1554         if (!evsel)
1555                 return -EFAULT;
1556         return perf_evsel__parse_sample(evsel, event, sample);
1557 }
1558 
1559 size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp)
1560 {
1561         struct perf_evsel *evsel;
1562         size_t printed = 0;
1563 
1564         evlist__for_each(evlist, evsel) {
1565                 printed += fprintf(fp, "%s%s", evsel->idx ? ", " : "",
1566                                    perf_evsel__name(evsel));
1567         }
1568 
1569         return printed + fprintf(fp, "\n");
1570 }
1571 
1572 int perf_evlist__strerror_open(struct perf_evlist *evlist __maybe_unused,
1573                                int err, char *buf, size_t size)
1574 {
1575         int printed, value;
1576         char sbuf[STRERR_BUFSIZE], *emsg = strerror_r(err, sbuf, sizeof(sbuf));
1577 
1578         switch (err) {
1579         case EACCES:
1580         case EPERM:
1581                 printed = scnprintf(buf, size,
1582                                     "Error:\t%s.\n"
1583                                     "Hint:\tCheck /proc/sys/kernel/perf_event_paranoid setting.", emsg);
1584 
1585                 value = perf_event_paranoid();
1586 
1587                 printed += scnprintf(buf + printed, size - printed, "\nHint:\t");
1588 
1589                 if (value >= 2) {
1590                         printed += scnprintf(buf + printed, size - printed,
1591                                              "For your workloads it needs to be <= 1\nHint:\t");
1592                 }
1593                 printed += scnprintf(buf + printed, size - printed,
1594                                      "For system wide tracing it needs to be set to -1.\n");
1595 
1596                 printed += scnprintf(buf + printed, size - printed,
1597                                     "Hint:\tTry: 'sudo sh -c \"echo -1 > /proc/sys/kernel/perf_event_paranoid\"'\n"
1598                                     "Hint:\tThe current value is %d.", value);
1599                 break;
1600         default:
1601                 scnprintf(buf, size, "%s", emsg);
1602                 break;
1603         }
1604 
1605         return 0;
1606 }
1607 
1608 int perf_evlist__strerror_mmap(struct perf_evlist *evlist, int err, char *buf, size_t size)
1609 {
1610         char sbuf[STRERR_BUFSIZE], *emsg = strerror_r(err, sbuf, sizeof(sbuf));
1611         int pages_attempted = evlist->mmap_len / 1024, pages_max_per_user, printed = 0;
1612 
1613         switch (err) {
1614         case EPERM:
1615                 sysctl__read_int("kernel/perf_event_mlock_kb", &pages_max_per_user);
1616                 printed += scnprintf(buf + printed, size - printed,
1617                                      "Error:\t%s.\n"
1618                                      "Hint:\tCheck /proc/sys/kernel/perf_event_mlock_kb (%d kB) setting.\n"
1619                                      "Hint:\tTried using %zd kB.\n",
1620                                      emsg, pages_max_per_user, pages_attempted);
1621 
1622                 if (pages_attempted >= pages_max_per_user) {
1623                         printed += scnprintf(buf + printed, size - printed,
1624                                              "Hint:\tTry 'sudo sh -c \"echo %d > /proc/sys/kernel/perf_event_mlock_kb\"', or\n",
1625                                              pages_max_per_user + pages_attempted);
1626                 }
1627 
1628                 printed += scnprintf(buf + printed, size - printed,
1629                                      "Hint:\tTry using a smaller -m/--mmap-pages value.");
1630                 break;
1631         default:
1632                 scnprintf(buf, size, "%s", emsg);
1633                 break;
1634         }
1635 
1636         return 0;
1637 }
1638 
1639 void perf_evlist__to_front(struct perf_evlist *evlist,
1640                            struct perf_evsel *move_evsel)
1641 {
1642         struct perf_evsel *evsel, *n;
1643         LIST_HEAD(move);
1644 
1645         if (move_evsel == perf_evlist__first(evlist))
1646                 return;
1647 
1648         evlist__for_each_safe(evlist, n, evsel) {
1649                 if (evsel->leader == move_evsel->leader)
1650                         list_move_tail(&evsel->node, &move);
1651         }
1652 
1653         list_splice(&move, &evlist->entries);
1654 }
1655 
1656 void perf_evlist__set_tracking_event(struct perf_evlist *evlist,
1657                                      struct perf_evsel *tracking_evsel)
1658 {
1659         struct perf_evsel *evsel;
1660 
1661         if (tracking_evsel->tracking)
1662                 return;
1663 
1664         evlist__for_each(evlist, evsel) {
1665                 if (evsel != tracking_evsel)
1666                         evsel->tracking = false;
1667         }
1668 
1669         tracking_evsel->tracking = true;
1670 }
1671 

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