perf tools: Introduce tools/lib/lk library
[linux-3.10.git] / tools / perf / util / evlist.c
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 <lk/debugfs.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 <unistd.h>
18
19 #include "parse-events.h"
20
21 #include <sys/mman.h>
22
23 #include <linux/bitops.h>
24 #include <linux/hash.h>
25
26 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
27 #define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
28
29 void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
30                        struct thread_map *threads)
31 {
32         int i;
33
34         for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
35                 INIT_HLIST_HEAD(&evlist->heads[i]);
36         INIT_LIST_HEAD(&evlist->entries);
37         perf_evlist__set_maps(evlist, cpus, threads);
38         evlist->workload.pid = -1;
39 }
40
41 struct perf_evlist *perf_evlist__new(struct cpu_map *cpus,
42                                      struct thread_map *threads)
43 {
44         struct perf_evlist *evlist = zalloc(sizeof(*evlist));
45
46         if (evlist != NULL)
47                 perf_evlist__init(evlist, cpus, threads);
48
49         return evlist;
50 }
51
52 void perf_evlist__config(struct perf_evlist *evlist,
53                         struct perf_record_opts *opts)
54 {
55         struct perf_evsel *evsel;
56         /*
57          * Set the evsel leader links before we configure attributes,
58          * since some might depend on this info.
59          */
60         if (opts->group)
61                 perf_evlist__set_leader(evlist);
62
63         if (evlist->cpus->map[0] < 0)
64                 opts->no_inherit = true;
65
66         list_for_each_entry(evsel, &evlist->entries, node) {
67                 perf_evsel__config(evsel, opts);
68
69                 if (evlist->nr_entries > 1)
70                         perf_evsel__set_sample_id(evsel);
71         }
72 }
73
74 static void perf_evlist__purge(struct perf_evlist *evlist)
75 {
76         struct perf_evsel *pos, *n;
77
78         list_for_each_entry_safe(pos, n, &evlist->entries, node) {
79                 list_del_init(&pos->node);
80                 perf_evsel__delete(pos);
81         }
82
83         evlist->nr_entries = 0;
84 }
85
86 void perf_evlist__exit(struct perf_evlist *evlist)
87 {
88         free(evlist->mmap);
89         free(evlist->pollfd);
90         evlist->mmap = NULL;
91         evlist->pollfd = NULL;
92 }
93
94 void perf_evlist__delete(struct perf_evlist *evlist)
95 {
96         perf_evlist__purge(evlist);
97         perf_evlist__exit(evlist);
98         free(evlist);
99 }
100
101 void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry)
102 {
103         list_add_tail(&entry->node, &evlist->entries);
104         ++evlist->nr_entries;
105 }
106
107 void perf_evlist__splice_list_tail(struct perf_evlist *evlist,
108                                    struct list_head *list,
109                                    int nr_entries)
110 {
111         list_splice_tail(list, &evlist->entries);
112         evlist->nr_entries += nr_entries;
113 }
114
115 void __perf_evlist__set_leader(struct list_head *list)
116 {
117         struct perf_evsel *evsel, *leader;
118
119         leader = list_entry(list->next, struct perf_evsel, node);
120         evsel = list_entry(list->prev, struct perf_evsel, node);
121
122         leader->nr_members = evsel->idx - leader->idx + 1;
123
124         list_for_each_entry(evsel, list, node) {
125                 evsel->leader = leader;
126         }
127 }
128
129 void perf_evlist__set_leader(struct perf_evlist *evlist)
130 {
131         if (evlist->nr_entries) {
132                 evlist->nr_groups = evlist->nr_entries > 1 ? 1 : 0;
133                 __perf_evlist__set_leader(&evlist->entries);
134         }
135 }
136
137 int perf_evlist__add_default(struct perf_evlist *evlist)
138 {
139         struct perf_event_attr attr = {
140                 .type = PERF_TYPE_HARDWARE,
141                 .config = PERF_COUNT_HW_CPU_CYCLES,
142         };
143         struct perf_evsel *evsel;
144
145         event_attr_init(&attr);
146
147         evsel = perf_evsel__new(&attr, 0);
148         if (evsel == NULL)
149                 goto error;
150
151         /* use strdup() because free(evsel) assumes name is allocated */
152         evsel->name = strdup("cycles");
153         if (!evsel->name)
154                 goto error_free;
155
156         perf_evlist__add(evlist, evsel);
157         return 0;
158 error_free:
159         perf_evsel__delete(evsel);
160 error:
161         return -ENOMEM;
162 }
163
164 static int perf_evlist__add_attrs(struct perf_evlist *evlist,
165                                   struct perf_event_attr *attrs, size_t nr_attrs)
166 {
167         struct perf_evsel *evsel, *n;
168         LIST_HEAD(head);
169         size_t i;
170
171         for (i = 0; i < nr_attrs; i++) {
172                 evsel = perf_evsel__new(attrs + i, evlist->nr_entries + i);
173                 if (evsel == NULL)
174                         goto out_delete_partial_list;
175                 list_add_tail(&evsel->node, &head);
176         }
177
178         perf_evlist__splice_list_tail(evlist, &head, nr_attrs);
179
180         return 0;
181
182 out_delete_partial_list:
183         list_for_each_entry_safe(evsel, n, &head, node)
184                 perf_evsel__delete(evsel);
185         return -1;
186 }
187
188 int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
189                                      struct perf_event_attr *attrs, size_t nr_attrs)
190 {
191         size_t i;
192
193         for (i = 0; i < nr_attrs; i++)
194                 event_attr_init(attrs + i);
195
196         return perf_evlist__add_attrs(evlist, attrs, nr_attrs);
197 }
198
199 struct perf_evsel *
200 perf_evlist__find_tracepoint_by_id(struct perf_evlist *evlist, int id)
201 {
202         struct perf_evsel *evsel;
203
204         list_for_each_entry(evsel, &evlist->entries, node) {
205                 if (evsel->attr.type   == PERF_TYPE_TRACEPOINT &&
206                     (int)evsel->attr.config == id)
207                         return evsel;
208         }
209
210         return NULL;
211 }
212
213 int perf_evlist__add_newtp(struct perf_evlist *evlist,
214                            const char *sys, const char *name, void *handler)
215 {
216         struct perf_evsel *evsel;
217
218         evsel = perf_evsel__newtp(sys, name, evlist->nr_entries);
219         if (evsel == NULL)
220                 return -1;
221
222         evsel->handler.func = handler;
223         perf_evlist__add(evlist, evsel);
224         return 0;
225 }
226
227 void perf_evlist__disable(struct perf_evlist *evlist)
228 {
229         int cpu, thread;
230         struct perf_evsel *pos;
231
232         for (cpu = 0; cpu < evlist->cpus->nr; cpu++) {
233                 list_for_each_entry(pos, &evlist->entries, node) {
234                         if (!perf_evsel__is_group_leader(pos))
235                                 continue;
236                         for (thread = 0; thread < evlist->threads->nr; thread++)
237                                 ioctl(FD(pos, cpu, thread),
238                                       PERF_EVENT_IOC_DISABLE, 0);
239                 }
240         }
241 }
242
243 void perf_evlist__enable(struct perf_evlist *evlist)
244 {
245         int cpu, thread;
246         struct perf_evsel *pos;
247
248         for (cpu = 0; cpu < cpu_map__nr(evlist->cpus); cpu++) {
249                 list_for_each_entry(pos, &evlist->entries, node) {
250                         if (!perf_evsel__is_group_leader(pos))
251                                 continue;
252                         for (thread = 0; thread < evlist->threads->nr; thread++)
253                                 ioctl(FD(pos, cpu, thread),
254                                       PERF_EVENT_IOC_ENABLE, 0);
255                 }
256         }
257 }
258
259 static int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
260 {
261         int nfds = cpu_map__nr(evlist->cpus) * evlist->threads->nr * evlist->nr_entries;
262         evlist->pollfd = malloc(sizeof(struct pollfd) * nfds);
263         return evlist->pollfd != NULL ? 0 : -ENOMEM;
264 }
265
266 void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
267 {
268         fcntl(fd, F_SETFL, O_NONBLOCK);
269         evlist->pollfd[evlist->nr_fds].fd = fd;
270         evlist->pollfd[evlist->nr_fds].events = POLLIN;
271         evlist->nr_fds++;
272 }
273
274 static void perf_evlist__id_hash(struct perf_evlist *evlist,
275                                  struct perf_evsel *evsel,
276                                  int cpu, int thread, u64 id)
277 {
278         int hash;
279         struct perf_sample_id *sid = SID(evsel, cpu, thread);
280
281         sid->id = id;
282         sid->evsel = evsel;
283         hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
284         hlist_add_head(&sid->node, &evlist->heads[hash]);
285 }
286
287 void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel,
288                          int cpu, int thread, u64 id)
289 {
290         perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
291         evsel->id[evsel->ids++] = id;
292 }
293
294 static int perf_evlist__id_add_fd(struct perf_evlist *evlist,
295                                   struct perf_evsel *evsel,
296                                   int cpu, int thread, int fd)
297 {
298         u64 read_data[4] = { 0, };
299         int id_idx = 1; /* The first entry is the counter value */
300
301         if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
302             read(fd, &read_data, sizeof(read_data)) == -1)
303                 return -1;
304
305         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
306                 ++id_idx;
307         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
308                 ++id_idx;
309
310         perf_evlist__id_add(evlist, evsel, cpu, thread, read_data[id_idx]);
311         return 0;
312 }
313
314 struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
315 {
316         struct hlist_head *head;
317         struct hlist_node *pos;
318         struct perf_sample_id *sid;
319         int hash;
320
321         if (evlist->nr_entries == 1)
322                 return perf_evlist__first(evlist);
323
324         hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
325         head = &evlist->heads[hash];
326
327         hlist_for_each_entry(sid, pos, head, node)
328                 if (sid->id == id)
329                         return sid->evsel;
330
331         if (!perf_evlist__sample_id_all(evlist))
332                 return perf_evlist__first(evlist);
333
334         return NULL;
335 }
336
337 union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
338 {
339         struct perf_mmap *md = &evlist->mmap[idx];
340         unsigned int head = perf_mmap__read_head(md);
341         unsigned int old = md->prev;
342         unsigned char *data = md->base + page_size;
343         union perf_event *event = NULL;
344
345         if (evlist->overwrite) {
346                 /*
347                  * If we're further behind than half the buffer, there's a chance
348                  * the writer will bite our tail and mess up the samples under us.
349                  *
350                  * If we somehow ended up ahead of the head, we got messed up.
351                  *
352                  * In either case, truncate and restart at head.
353                  */
354                 int diff = head - old;
355                 if (diff > md->mask / 2 || diff < 0) {
356                         fprintf(stderr, "WARNING: failed to keep up with mmap data.\n");
357
358                         /*
359                          * head points to a known good entry, start there.
360                          */
361                         old = head;
362                 }
363         }
364
365         if (old != head) {
366                 size_t size;
367
368                 event = (union perf_event *)&data[old & md->mask];
369                 size = event->header.size;
370
371                 /*
372                  * Event straddles the mmap boundary -- header should always
373                  * be inside due to u64 alignment of output.
374                  */
375                 if ((old & md->mask) + size != ((old + size) & md->mask)) {
376                         unsigned int offset = old;
377                         unsigned int len = min(sizeof(*event), size), cpy;
378                         void *dst = &md->event_copy;
379
380                         do {
381                                 cpy = min(md->mask + 1 - (offset & md->mask), len);
382                                 memcpy(dst, &data[offset & md->mask], cpy);
383                                 offset += cpy;
384                                 dst += cpy;
385                                 len -= cpy;
386                         } while (len);
387
388                         event = &md->event_copy;
389                 }
390
391                 old += size;
392         }
393
394         md->prev = old;
395
396         if (!evlist->overwrite)
397                 perf_mmap__write_tail(md, old);
398
399         return event;
400 }
401
402 void perf_evlist__munmap(struct perf_evlist *evlist)
403 {
404         int i;
405
406         for (i = 0; i < evlist->nr_mmaps; i++) {
407                 if (evlist->mmap[i].base != NULL) {
408                         munmap(evlist->mmap[i].base, evlist->mmap_len);
409                         evlist->mmap[i].base = NULL;
410                 }
411         }
412
413         free(evlist->mmap);
414         evlist->mmap = NULL;
415 }
416
417 static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
418 {
419         evlist->nr_mmaps = cpu_map__nr(evlist->cpus);
420         if (cpu_map__all(evlist->cpus))
421                 evlist->nr_mmaps = evlist->threads->nr;
422         evlist->mmap = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
423         return evlist->mmap != NULL ? 0 : -ENOMEM;
424 }
425
426 static int __perf_evlist__mmap(struct perf_evlist *evlist,
427                                int idx, int prot, int mask, int fd)
428 {
429         evlist->mmap[idx].prev = 0;
430         evlist->mmap[idx].mask = mask;
431         evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, prot,
432                                       MAP_SHARED, fd, 0);
433         if (evlist->mmap[idx].base == MAP_FAILED) {
434                 evlist->mmap[idx].base = NULL;
435                 return -1;
436         }
437
438         perf_evlist__add_pollfd(evlist, fd);
439         return 0;
440 }
441
442 static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist, int prot, int mask)
443 {
444         struct perf_evsel *evsel;
445         int cpu, thread;
446
447         for (cpu = 0; cpu < evlist->cpus->nr; cpu++) {
448                 int output = -1;
449
450                 for (thread = 0; thread < evlist->threads->nr; thread++) {
451                         list_for_each_entry(evsel, &evlist->entries, node) {
452                                 int fd = FD(evsel, cpu, thread);
453
454                                 if (output == -1) {
455                                         output = fd;
456                                         if (__perf_evlist__mmap(evlist, cpu,
457                                                                 prot, mask, output) < 0)
458                                                 goto out_unmap;
459                                 } else {
460                                         if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, output) != 0)
461                                                 goto out_unmap;
462                                 }
463
464                                 if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
465                                     perf_evlist__id_add_fd(evlist, evsel, cpu, thread, fd) < 0)
466                                         goto out_unmap;
467                         }
468                 }
469         }
470
471         return 0;
472
473 out_unmap:
474         for (cpu = 0; cpu < evlist->cpus->nr; cpu++) {
475                 if (evlist->mmap[cpu].base != NULL) {
476                         munmap(evlist->mmap[cpu].base, evlist->mmap_len);
477                         evlist->mmap[cpu].base = NULL;
478                 }
479         }
480         return -1;
481 }
482
483 static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist, int prot, int mask)
484 {
485         struct perf_evsel *evsel;
486         int thread;
487
488         for (thread = 0; thread < evlist->threads->nr; thread++) {
489                 int output = -1;
490
491                 list_for_each_entry(evsel, &evlist->entries, node) {
492                         int fd = FD(evsel, 0, thread);
493
494                         if (output == -1) {
495                                 output = fd;
496                                 if (__perf_evlist__mmap(evlist, thread,
497                                                         prot, mask, output) < 0)
498                                         goto out_unmap;
499                         } else {
500                                 if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, output) != 0)
501                                         goto out_unmap;
502                         }
503
504                         if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
505                             perf_evlist__id_add_fd(evlist, evsel, 0, thread, fd) < 0)
506                                 goto out_unmap;
507                 }
508         }
509
510         return 0;
511
512 out_unmap:
513         for (thread = 0; thread < evlist->threads->nr; thread++) {
514                 if (evlist->mmap[thread].base != NULL) {
515                         munmap(evlist->mmap[thread].base, evlist->mmap_len);
516                         evlist->mmap[thread].base = NULL;
517                 }
518         }
519         return -1;
520 }
521
522 /** perf_evlist__mmap - Create per cpu maps to receive events
523  *
524  * @evlist - list of events
525  * @pages - map length in pages
526  * @overwrite - overwrite older events?
527  *
528  * If overwrite is false the user needs to signal event consuption using:
529  *
530  *      struct perf_mmap *m = &evlist->mmap[cpu];
531  *      unsigned int head = perf_mmap__read_head(m);
532  *
533  *      perf_mmap__write_tail(m, head)
534  *
535  * Using perf_evlist__read_on_cpu does this automatically.
536  */
537 int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
538                       bool overwrite)
539 {
540         struct perf_evsel *evsel;
541         const struct cpu_map *cpus = evlist->cpus;
542         const struct thread_map *threads = evlist->threads;
543         int prot = PROT_READ | (overwrite ? 0 : PROT_WRITE), mask;
544
545         /* 512 kiB: default amount of unprivileged mlocked memory */
546         if (pages == UINT_MAX)
547                 pages = (512 * 1024) / page_size;
548         else if (!is_power_of_2(pages))
549                 return -EINVAL;
550
551         mask = pages * page_size - 1;
552
553         if (evlist->mmap == NULL && perf_evlist__alloc_mmap(evlist) < 0)
554                 return -ENOMEM;
555
556         if (evlist->pollfd == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
557                 return -ENOMEM;
558
559         evlist->overwrite = overwrite;
560         evlist->mmap_len = (pages + 1) * page_size;
561
562         list_for_each_entry(evsel, &evlist->entries, node) {
563                 if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
564                     evsel->sample_id == NULL &&
565                     perf_evsel__alloc_id(evsel, cpu_map__nr(cpus), threads->nr) < 0)
566                         return -ENOMEM;
567         }
568
569         if (cpu_map__all(cpus))
570                 return perf_evlist__mmap_per_thread(evlist, prot, mask);
571
572         return perf_evlist__mmap_per_cpu(evlist, prot, mask);
573 }
574
575 int perf_evlist__create_maps(struct perf_evlist *evlist,
576                              struct perf_target *target)
577 {
578         evlist->threads = thread_map__new_str(target->pid, target->tid,
579                                               target->uid);
580
581         if (evlist->threads == NULL)
582                 return -1;
583
584         if (perf_target__has_task(target))
585                 evlist->cpus = cpu_map__dummy_new();
586         else if (!perf_target__has_cpu(target) && !target->uses_mmap)
587                 evlist->cpus = cpu_map__dummy_new();
588         else
589                 evlist->cpus = cpu_map__new(target->cpu_list);
590
591         if (evlist->cpus == NULL)
592                 goto out_delete_threads;
593
594         return 0;
595
596 out_delete_threads:
597         thread_map__delete(evlist->threads);
598         return -1;
599 }
600
601 void perf_evlist__delete_maps(struct perf_evlist *evlist)
602 {
603         cpu_map__delete(evlist->cpus);
604         thread_map__delete(evlist->threads);
605         evlist->cpus    = NULL;
606         evlist->threads = NULL;
607 }
608
609 int perf_evlist__apply_filters(struct perf_evlist *evlist)
610 {
611         struct perf_evsel *evsel;
612         int err = 0;
613         const int ncpus = cpu_map__nr(evlist->cpus),
614                   nthreads = evlist->threads->nr;
615
616         list_for_each_entry(evsel, &evlist->entries, node) {
617                 if (evsel->filter == NULL)
618                         continue;
619
620                 err = perf_evsel__set_filter(evsel, ncpus, nthreads, evsel->filter);
621                 if (err)
622                         break;
623         }
624
625         return err;
626 }
627
628 int perf_evlist__set_filter(struct perf_evlist *evlist, const char *filter)
629 {
630         struct perf_evsel *evsel;
631         int err = 0;
632         const int ncpus = cpu_map__nr(evlist->cpus),
633                   nthreads = evlist->threads->nr;
634
635         list_for_each_entry(evsel, &evlist->entries, node) {
636                 err = perf_evsel__set_filter(evsel, ncpus, nthreads, filter);
637                 if (err)
638                         break;
639         }
640
641         return err;
642 }
643
644 bool perf_evlist__valid_sample_type(struct perf_evlist *evlist)
645 {
646         struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;
647
648         list_for_each_entry_continue(pos, &evlist->entries, node) {
649                 if (first->attr.sample_type != pos->attr.sample_type)
650                         return false;
651         }
652
653         return true;
654 }
655
656 u64 perf_evlist__sample_type(struct perf_evlist *evlist)
657 {
658         struct perf_evsel *first = perf_evlist__first(evlist);
659         return first->attr.sample_type;
660 }
661
662 u16 perf_evlist__id_hdr_size(struct perf_evlist *evlist)
663 {
664         struct perf_evsel *first = perf_evlist__first(evlist);
665         struct perf_sample *data;
666         u64 sample_type;
667         u16 size = 0;
668
669         if (!first->attr.sample_id_all)
670                 goto out;
671
672         sample_type = first->attr.sample_type;
673
674         if (sample_type & PERF_SAMPLE_TID)
675                 size += sizeof(data->tid) * 2;
676
677        if (sample_type & PERF_SAMPLE_TIME)
678                 size += sizeof(data->time);
679
680         if (sample_type & PERF_SAMPLE_ID)
681                 size += sizeof(data->id);
682
683         if (sample_type & PERF_SAMPLE_STREAM_ID)
684                 size += sizeof(data->stream_id);
685
686         if (sample_type & PERF_SAMPLE_CPU)
687                 size += sizeof(data->cpu) * 2;
688 out:
689         return size;
690 }
691
692 bool perf_evlist__valid_sample_id_all(struct perf_evlist *evlist)
693 {
694         struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;
695
696         list_for_each_entry_continue(pos, &evlist->entries, node) {
697                 if (first->attr.sample_id_all != pos->attr.sample_id_all)
698                         return false;
699         }
700
701         return true;
702 }
703
704 bool perf_evlist__sample_id_all(struct perf_evlist *evlist)
705 {
706         struct perf_evsel *first = perf_evlist__first(evlist);
707         return first->attr.sample_id_all;
708 }
709
710 void perf_evlist__set_selected(struct perf_evlist *evlist,
711                                struct perf_evsel *evsel)
712 {
713         evlist->selected = evsel;
714 }
715
716 int perf_evlist__open(struct perf_evlist *evlist)
717 {
718         struct perf_evsel *evsel;
719         int err, ncpus, nthreads;
720
721         list_for_each_entry(evsel, &evlist->entries, node) {
722                 err = perf_evsel__open(evsel, evlist->cpus, evlist->threads);
723                 if (err < 0)
724                         goto out_err;
725         }
726
727         return 0;
728 out_err:
729         ncpus = evlist->cpus ? evlist->cpus->nr : 1;
730         nthreads = evlist->threads ? evlist->threads->nr : 1;
731
732         list_for_each_entry_reverse(evsel, &evlist->entries, node)
733                 perf_evsel__close(evsel, ncpus, nthreads);
734
735         errno = -err;
736         return err;
737 }
738
739 int perf_evlist__prepare_workload(struct perf_evlist *evlist,
740                                   struct perf_record_opts *opts,
741                                   const char *argv[])
742 {
743         int child_ready_pipe[2], go_pipe[2];
744         char bf;
745
746         if (pipe(child_ready_pipe) < 0) {
747                 perror("failed to create 'ready' pipe");
748                 return -1;
749         }
750
751         if (pipe(go_pipe) < 0) {
752                 perror("failed to create 'go' pipe");
753                 goto out_close_ready_pipe;
754         }
755
756         evlist->workload.pid = fork();
757         if (evlist->workload.pid < 0) {
758                 perror("failed to fork");
759                 goto out_close_pipes;
760         }
761
762         if (!evlist->workload.pid) {
763                 if (opts->pipe_output)
764                         dup2(2, 1);
765
766                 close(child_ready_pipe[0]);
767                 close(go_pipe[1]);
768                 fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
769
770                 /*
771                  * Do a dummy execvp to get the PLT entry resolved,
772                  * so we avoid the resolver overhead on the real
773                  * execvp call.
774                  */
775                 execvp("", (char **)argv);
776
777                 /*
778                  * Tell the parent we're ready to go
779                  */
780                 close(child_ready_pipe[1]);
781
782                 /*
783                  * Wait until the parent tells us to go.
784                  */
785                 if (read(go_pipe[0], &bf, 1) == -1)
786                         perror("unable to read pipe");
787
788                 execvp(argv[0], (char **)argv);
789
790                 perror(argv[0]);
791                 kill(getppid(), SIGUSR1);
792                 exit(-1);
793         }
794
795         if (perf_target__none(&opts->target))
796                 evlist->threads->map[0] = evlist->workload.pid;
797
798         close(child_ready_pipe[1]);
799         close(go_pipe[0]);
800         /*
801          * wait for child to settle
802          */
803         if (read(child_ready_pipe[0], &bf, 1) == -1) {
804                 perror("unable to read pipe");
805                 goto out_close_pipes;
806         }
807
808         evlist->workload.cork_fd = go_pipe[1];
809         close(child_ready_pipe[0]);
810         return 0;
811
812 out_close_pipes:
813         close(go_pipe[0]);
814         close(go_pipe[1]);
815 out_close_ready_pipe:
816         close(child_ready_pipe[0]);
817         close(child_ready_pipe[1]);
818         return -1;
819 }
820
821 int perf_evlist__start_workload(struct perf_evlist *evlist)
822 {
823         if (evlist->workload.cork_fd > 0) {
824                 /*
825                  * Remove the cork, let it rip!
826                  */
827                 return close(evlist->workload.cork_fd);
828         }
829
830         return 0;
831 }
832
833 int perf_evlist__parse_sample(struct perf_evlist *evlist, union perf_event *event,
834                               struct perf_sample *sample)
835 {
836         struct perf_evsel *evsel = perf_evlist__first(evlist);
837         return perf_evsel__parse_sample(evsel, event, sample);
838 }
839
840 size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp)
841 {
842         struct perf_evsel *evsel;
843         size_t printed = 0;
844
845         list_for_each_entry(evsel, &evlist->entries, node) {
846                 printed += fprintf(fp, "%s%s", evsel->idx ? ", " : "",
847                                    perf_evsel__name(evsel));
848         }
849
850         return printed + fprintf(fp, "\n");;
851 }