summaryrefslogtreecommitdiffstats
path: root/tools/perf/util/evlist.c
blob: 291884c804e9dd2e1925bd6eb158502e1e94f302 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
/*
 * Copyright (C) 2011, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
 *
 * Parts came from builtin-{top,stat,record}.c, see those files for further
 * copyright notes.
 *
 * Released under the GPL v2. (and only v2, not any later version)
 */
#include "util.h"
#include <lk/debugfs.h>
#include <poll.h>
#include "cpumap.h"
#include "thread_map.h"
#include "target.h"
#include "evlist.h"
#include "evsel.h"
#include <unistd.h>

#include "parse-events.h"

#include <sys/mman.h>

#include <linux/bitops.h>
#include <linux/hash.h>

#define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
#define SID(e, x, y) xyarray__entry(e->sample_id, x, y)

void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
		       struct thread_map *threads)
{
	int i;

	for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
		INIT_HLIST_HEAD(&evlist->heads[i]);
	INIT_LIST_HEAD(&evlist->entries);
	perf_evlist__set_maps(evlist, cpus, threads);
	evlist->workload.pid = -1;
}

struct perf_evlist *perf_evlist__new(void)
{
	struct perf_evlist *evlist = zalloc(sizeof(*evlist));

	if (evlist != NULL)
		perf_evlist__init(evlist, NULL, NULL);

	return evlist;
}

void perf_evlist__config(struct perf_evlist *evlist,
			struct perf_record_opts *opts)
{
	struct perf_evsel *evsel;
	/*
	 * Set the evsel leader links before we configure attributes,
	 * since some might depend on this info.
	 */
	if (opts->group)
		perf_evlist__set_leader(evlist);

	if (evlist->cpus->map[0] < 0)
		opts->no_inherit = true;

	list_for_each_entry(evsel, &evlist->entries, node) {
		perf_evsel__config(evsel, opts);

		if (evlist->nr_entries > 1)
			perf_evsel__set_sample_id(evsel);
	}
}

static void perf_evlist__purge(struct perf_evlist *evlist)
{
	struct perf_evsel *pos, *n;

	list_for_each_entry_safe(pos, n, &evlist->entries, node) {
		list_del_init(&pos->node);
		perf_evsel__delete(pos);
	}

	evlist->nr_entries = 0;
}

void perf_evlist__exit(struct perf_evlist *evlist)
{
	free(evlist->mmap);
	free(evlist->pollfd);
	evlist->mmap = NULL;
	evlist->pollfd = NULL;
}

void perf_evlist__delete(struct perf_evlist *evlist)
{
	perf_evlist__purge(evlist);
	perf_evlist__exit(evlist);
	free(evlist);
}

void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry)
{
	list_add_tail(&entry->node, &evlist->entries);
	++evlist->nr_entries;
}

void perf_evlist__splice_list_tail(struct perf_evlist *evlist,
				   struct list_head *list,
				   int nr_entries)
{
	list_splice_tail(list, &evlist->entries);
	evlist->nr_entries += nr_entries;
}

void __perf_evlist__set_leader(struct list_head *list)
{
	struct perf_evsel *evsel, *leader;

	leader = list_entry(list->next, struct perf_evsel, node);
	evsel = list_entry(list->prev, struct perf_evsel, node);

	leader->nr_members = evsel->idx - leader->idx + 1;

	list_for_each_entry(evsel, list, node) {
		evsel->leader = leader;
	}
}

void perf_evlist__set_leader(struct perf_evlist *evlist)
{
	if (evlist->nr_entries) {
		evlist->nr_groups = evlist->nr_entries > 1 ? 1 : 0;
		__perf_evlist__set_leader(&evlist->entries);
	}
}

int perf_evlist__add_default(struct perf_evlist *evlist)
{
	struct perf_event_attr attr = {
		.type = PERF_TYPE_HARDWARE,
		.config = PERF_COUNT_HW_CPU_CYCLES,
	};
	struct perf_evsel *evsel;

	event_attr_init(&attr);

	evsel = perf_evsel__new(&attr, 0);
	if (evsel == NULL)
		goto error;

	/* use strdup() because free(evsel) assumes name is allocated */
	evsel->name = strdup("cycles");
	if (!evsel->name)
		goto error_free;

	perf_evlist__add(evlist, evsel);
	return 0;
error_free:
	perf_evsel__delete(evsel);
error:
	return -ENOMEM;
}

static int perf_evlist__add_attrs(struct perf_evlist *evlist,
				  struct perf_event_attr *attrs, size_t nr_attrs)
{
	struct perf_evsel *evsel, *n;
	LIST_HEAD(head);
	size_t i;

	for (i = 0; i < nr_attrs; i++) {
		evsel = perf_evsel__new(attrs + i, evlist->nr_entries + i);
		if (evsel == NULL)
			goto out_delete_partial_list;
		list_add_tail(&evsel->node, &head);
	}

	perf_evlist__splice_list_tail(evlist, &head, nr_attrs);

	return 0;

out_delete_partial_list:
	list_for_each_entry_safe(evsel, n, &head, node)
		perf_evsel__delete(evsel);
	return -1;
}

int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
				     struct perf_event_attr *attrs, size_t nr_attrs)
{
	size_t i;

	for (i = 0; i < nr_attrs; i++)
		event_attr_init(attrs + i);

	return perf_evlist__add_attrs(evlist, attrs, nr_attrs);
}

struct perf_evsel *
perf_evlist__find_tracepoint_by_id(struct perf_evlist *evlist, int id)
{
	struct perf_evsel *evsel;

	list_for_each_entry(evsel, &evlist->entries, node) {
		if (evsel->attr.type   == PERF_TYPE_TRACEPOINT &&
		    (int)evsel->attr.config == id)
			return evsel;
	}

	return NULL;
}

int perf_evlist__add_newtp(struct perf_evlist *evlist,
			   const char *sys, const char *name, void *handler)
{
	struct perf_evsel *evsel;

	evsel = perf_evsel__newtp(sys, name, evlist->nr_entries);
	if (evsel == NULL)
		return -1;

	evsel->handler.func = handler;
	perf_evlist__add(evlist, evsel);
	return 0;
}

void perf_evlist__disable(struct perf_evlist *evlist)
{
	int cpu, thread;
	struct perf_evsel *pos;
	int nr_cpus = cpu_map__nr(evlist->cpus);
	int nr_threads = thread_map__nr(evlist->threads);

	for (cpu = 0; cpu < nr_cpus; cpu++) {
		list_for_each_entry(pos, &evlist->entries, node) {
			if (!perf_evsel__is_group_leader(pos))
				continue;
			for (thread = 0; thread < nr_threads; thread++)
				ioctl(FD(pos, cpu, thread),
				      PERF_EVENT_IOC_DISABLE, 0);
		}
	}
}

void perf_evlist__enable(struct perf_evlist *evlist)
{
	int cpu, thread;
	struct perf_evsel *pos;
	int nr_cpus = cpu_map__nr(evlist->cpus);
	int nr_threads = thread_map__nr(evlist->threads);

	for (cpu = 0; cpu < nr_cpus; cpu++) {
		list_for_each_entry(pos, &evlist->entries, node) {
			if (!perf_evsel__is_group_leader(pos))
				continue;
			for (thread = 0; thread < nr_threads; thread++)
				ioctl(FD(pos, cpu, thread),
				      PERF_EVENT_IOC_ENABLE, 0);
		}
	}
}

static int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
{
	int nr_cpus = cpu_map__nr(evlist->cpus);
	int nr_threads = thread_map__nr(evlist->threads);
	int nfds = nr_cpus * nr_threads * evlist->nr_entries;
	evlist->pollfd = malloc(sizeof(struct pollfd) * nfds);
	return evlist->pollfd != NULL ? 0 : -ENOMEM;
}

void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
{
	fcntl(fd, F_SETFL, O_NONBLOCK);
	evlist->pollfd[evlist->nr_fds].fd = fd;
	evlist->pollfd[evlist->nr_fds].events = POLLIN;
	evlist->nr_fds++;
}

static void perf_evlist__id_hash(struct perf_evlist *evlist,
				 struct perf_evsel *evsel,
				 int cpu, int thread, u64 id)
{
	int hash;
	struct perf_sample_id *sid = SID(evsel, cpu, thread);

	sid->id = id;
	sid->evsel = evsel;
	hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
	hlist_add_head(&sid->node, &evlist->heads[hash]);
}

void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel,
			 int cpu, int thread, u64 id)
{
	perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
	evsel->id[evsel->ids++] = id;
}

static int perf_evlist__id_add_fd(struct perf_evlist *evlist,
				  struct perf_evsel *evsel,
				  int cpu, int thread, int fd)
{
	u64 read_data[4] = { 0, };
	int id_idx = 1; /* The first entry is the counter value */

	if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
	    read(fd, &read_data, sizeof(read_data)) == -1)
		return -1;

	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
		++id_idx;
	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
		++id_idx;

	perf_evlist__id_add(evlist, evsel, cpu, thread, read_data[id_idx]);
	return 0;
}

struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
{
	struct hlist_head *head;
	struct hlist_node *pos;
	struct perf_sample_id *sid;
	int hash;

	if (evlist->nr_entries == 1)
		return perf_evlist__first(evlist);

	hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
	head = &evlist->heads[hash];

	hlist_for_each_entry(sid, pos, head, node)
		if (sid->id == id)
			return sid->evsel;

	if (!perf_evlist__sample_id_all(evlist))
		return perf_evlist__first(evlist);

	return NULL;
}

union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
{
	struct perf_mmap *md = &evlist->mmap[idx];
	unsigned int head = perf_mmap__read_head(md);
	unsigned int old = md->prev;
	unsigned char *data = md->base + page_size;
	union perf_event *event = NULL;

	if (evlist->overwrite) {
		/*
		 * If we're further behind than half the buffer, there's a chance
		 * the writer will bite our tail and mess up the samples under us.
		 *
		 * If we somehow ended up ahead of the head, we got messed up.
		 *
		 * In either case, truncate and restart at head.
		 */
		int diff = head - old;
		if (diff > md->mask / 2 || diff < 0) {
			fprintf(stderr, "WARNING: failed to keep up with mmap data.\n");

			/*
			 * head points to a known good entry, start there.
			 */
			old = head;
		}
	}

	if (old != head) {
		size_t size;

		event = (union perf_event *)&data[old & md->mask];
		size = event->header.size;

		/*
		 * Event straddles the mmap boundary -- header should always
		 * be inside due to u64 alignment of output.
		 */
		if ((old & md->mask) + size != ((old + size) & md->mask)) {
			unsigned int offset = old;
			unsigned int len = min(sizeof(*event), size), cpy;
			void *dst = &md->event_copy;

			do {
				cpy = min(md->mask + 1 - (offset & md->mask), len);
				memcpy(dst, &data[offset & md->mask], cpy);
				offset += cpy;
				dst += cpy;
				len -= cpy;
			} while (len);

			event = &md->event_copy;
		}

		old += size;
	}

	md->prev = old;

	if (!evlist->overwrite)
		perf_mmap__write_tail(md, old);

	return event;
}

void perf_evlist__munmap(struct perf_evlist *evlist)
{
	int i;

	for (i = 0; i < evlist->nr_mmaps; i++) {
		if (evlist->mmap[i].base != NULL) {
			munmap(evlist->mmap[i].base, evlist->mmap_len);
			evlist->mmap[i].base = NULL;
		}
	}

	free(evlist->mmap);
	evlist->mmap = NULL;
}

static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
{
	evlist->nr_mmaps = cpu_map__nr(evlist->cpus);
	if (cpu_map__all(evlist->cpus))
		evlist->nr_mmaps = thread_map__nr(evlist->threads);
	evlist->mmap = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
	return evlist->mmap != NULL ? 0 : -ENOMEM;
}

static int __perf_evlist__mmap(struct perf_evlist *evlist,
			       int idx, int prot, int mask, int fd)
{
	evlist->mmap[idx].prev = 0;
	evlist->mmap[idx].mask = mask;
	evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, prot,
				      MAP_SHARED, fd, 0);
	if (evlist->mmap[idx].base == MAP_FAILED) {
		evlist->mmap[idx].base = NULL;
		return -1;
	}

	perf_evlist__add_pollfd(evlist, fd);
	return 0;
}

static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist, int prot, int mask)
{
	struct perf_evsel *evsel;
	int cpu, thread;
	int nr_cpus = cpu_map__nr(evlist->cpus);
	int nr_threads = thread_map__nr(evlist->threads);

	for (cpu = 0; cpu < nr_cpus; cpu++) {
		int output = -1;

		for (thread = 0; thread < nr_threads; thread++) {
			list_for_each_entry(evsel, &evlist->entries, node) {
				int fd = FD(evsel, cpu, thread);

				if (output == -1) {
					output = fd;
					if (__perf_evlist__mmap(evlist, cpu,
								prot, mask, output) < 0)
						goto out_unmap;
				} else {
					if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, output) != 0)
						goto out_unmap;
				}

				if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
				    perf_evlist__id_add_fd(evlist, evsel, cpu, thread, fd) < 0)
					goto out_unmap;
			}
		}
	}

	return 0;

out_unmap:
	for (cpu = 0; cpu < nr_cpus; cpu++) {
		if (evlist->mmap[cpu].base != NULL) {
			munmap(evlist->mmap[cpu].base, evlist->mmap_len);
			evlist->mmap[cpu].base = NULL;
		}
	}
	return -1;
}

static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist, int prot, int mask)
{
	struct perf_evsel *evsel;
	int thread;
	int nr_threads = thread_map__nr(evlist->threads);

	for (thread = 0; thread < nr_threads; thread++) {
		int output = -1;

		list_for_each_entry(evsel, &evlist->entries, node) {
			int fd = FD(evsel, 0, thread);

			if (output == -1) {
				output = fd;
				if (__perf_evlist__mmap(evlist, thread,
							prot, mask, output) < 0)
					goto out_unmap;
			} else {
				if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, output) != 0)
					goto out_unmap;
			}

			if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
			    perf_evlist__id_add_fd(evlist, evsel, 0, thread, fd) < 0)
				goto out_unmap;
		}
	}

	return 0;

out_unmap:
	for (thread = 0; thread < nr_threads; thread++) {
		if (evlist->mmap[thread].base != NULL) {
			munmap(evlist->mmap[thread].base, evlist->mmap_len);
			evlist->mmap[thread].base = NULL;
		}
	}
	return -1;
}

/** perf_evlist__mmap - Create per cpu maps to receive events
 *
 * @evlist - list of events
 * @pages - map length in pages
 * @overwrite - overwrite older events?
 *
 * If overwrite is false the user needs to signal event consuption using:
 *
 *	struct perf_mmap *m = &evlist->mmap[cpu];
 *	unsigned int head = perf_mmap__read_head(m);
 *
 *	perf_mmap__write_tail(m, head)
 *
 * Using perf_evlist__read_on_cpu does this automatically.
 */
int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
		      bool overwrite)
{
	struct perf_evsel *evsel;
	const struct cpu_map *cpus = evlist->cpus;
	const struct thread_map *threads = evlist->threads;
	int prot = PROT_READ | (overwrite ? 0 : PROT_WRITE), mask;

        /* 512 kiB: default amount of unprivileged mlocked memory */
        if (pages == UINT_MAX)
                pages = (512 * 1024) / page_size;
	else if (!is_power_of_2(pages))
		return -EINVAL;

	mask = pages * page_size - 1;

	if (evlist->mmap == NULL && perf_evlist__alloc_mmap(evlist) < 0)
		return -ENOMEM;

	if (evlist->pollfd == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
		return -ENOMEM;

	evlist->overwrite = overwrite;
	evlist->mmap_len = (pages + 1) * page_size;

	list_for_each_entry(evsel, &evlist->entries, node) {
		if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
		    evsel->sample_id == NULL &&
		    perf_evsel__alloc_id(evsel, cpu_map__nr(cpus), threads->nr) < 0)
			return -ENOMEM;
	}

	if (cpu_map__all(cpus))
		return perf_evlist__mmap_per_thread(evlist, prot, mask);

	return perf_evlist__mmap_per_cpu(evlist, prot, mask);
}

int perf_evlist__create_maps(struct perf_evlist *evlist,
			     struct perf_target *target)
{
	evlist->threads = thread_map__new_str(target->pid, target->tid,
					      target->uid);

	if (evlist->threads == NULL)
		return -1;

	if (perf_target__has_task(target))
		evlist->cpus = cpu_map__dummy_new();
	else if (!perf_target__has_cpu(target) && !target->uses_mmap)
		evlist->cpus = cpu_map__dummy_new();
	else
		evlist->cpus = cpu_map__new(target->cpu_list);

	if (evlist->cpus == NULL)
		goto out_delete_threads;

	return 0;

out_delete_threads:
	thread_map__delete(evlist->threads);
	return -1;
}

void perf_evlist__delete_maps(struct perf_evlist *evlist)
{
	cpu_map__delete(evlist->cpus);
	thread_map__delete(evlist->threads);
	evlist->cpus	= NULL;
	evlist->threads = NULL;
}

int perf_evlist__apply_filters(struct perf_evlist *evlist)
{
	struct perf_evsel *evsel;
	int err = 0;
	const int ncpus = cpu_map__nr(evlist->cpus),
		  nthreads = thread_map__nr(evlist->threads);

	list_for_each_entry(evsel, &evlist->entries, node) {
		if (evsel->filter == NULL)
			continue;

		err = perf_evsel__set_filter(evsel, ncpus, nthreads, evsel->filter);
		if (err)
			break;
	}

	return err;
}

int perf_evlist__set_filter(struct perf_evlist *evlist, const char *filter)
{
	struct perf_evsel *evsel;
	int err = 0;
	const int ncpus = cpu_map__nr(evlist->cpus),
		  nthreads = thread_map__nr(evlist->threads);

	list_for_each_entry(evsel, &evlist->entries, node) {
		err = perf_evsel__set_filter(evsel, ncpus, nthreads, filter);
		if (err)
			break;
	}

	return err;
}

bool perf_evlist__valid_sample_type(struct perf_evlist *evlist)
{
	struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;

	list_for_each_entry_continue(pos, &evlist->entries, node) {
		if (first->attr.sample_type != pos->attr.sample_type)
			return false;
	}

	return true;
}

u64 perf_evlist__sample_type(struct perf_evlist *evlist)
{
	struct perf_evsel *first = perf_evlist__first(evlist);
	return first->attr.sample_type;
}

u16 perf_evlist__id_hdr_size(struct perf_evlist *evlist)
{
	struct perf_evsel *first = perf_evlist__first(evlist);
	struct perf_sample *data;
	u64 sample_type;
	u16 size = 0;

	if (!first->attr.sample_id_all)
		goto out;

	sample_type = first->attr.sample_type;

	if (sample_type & PERF_SAMPLE_TID)
		size += sizeof(data->tid) * 2;

       if (sample_type & PERF_SAMPLE_TIME)
		size += sizeof(data->time);

	if (sample_type & PERF_SAMPLE_ID)
		size += sizeof(data->id);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		size += sizeof(data->stream_id);

	if (sample_type & PERF_SAMPLE_CPU)
		size += sizeof(data->cpu) * 2;
out:
	return size;
}

bool perf_evlist__valid_sample_id_all(struct perf_evlist *evlist)
{
	struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;

	list_for_each_entry_continue(pos, &evlist->entries, node) {
		if (first->attr.sample_id_all != pos->attr.sample_id_all)
			return false;
	}

	return true;
}

bool perf_evlist__sample_id_all(struct perf_evlist *evlist)
{
	struct perf_evsel *first = perf_evlist__first(evlist);
	return first->attr.sample_id_all;
}

void perf_evlist__set_selected(struct perf_evlist *evlist,
			       struct perf_evsel *evsel)
{
	evlist->selected = evsel;
}

int perf_evlist__open(struct perf_evlist *evlist)
{
	struct perf_evsel *evsel;
	int err, ncpus, nthreads;

	list_for_each_entry(evsel, &evlist->entries, node) {
		err = perf_evsel__open(evsel, evlist->cpus, evlist->threads);
		if (err < 0)
			goto out_err;
	}

	return 0;
out_err:
	ncpus = cpu_map__nr(evlist->cpus);
	nthreads = thread_map__nr(evlist->threads);

	list_for_each_entry_reverse(evsel, &evlist->entries, node)
		perf_evsel__close(evsel, ncpus, nthreads);

	errno = -err;
	return err;
}

int perf_evlist__prepare_workload(struct perf_evlist *evlist,
				  struct perf_target *target,
				  struct perf_record_opts *opts,
				  const char *argv[])
{
	int child_ready_pipe[2], go_pipe[2];
	char bf;

	if (pipe(child_ready_pipe) < 0) {
		perror("failed to create 'ready' pipe");
		return -1;
	}

	if (pipe(go_pipe) < 0) {
		perror("failed to create 'go' pipe");
		goto out_close_ready_pipe;
	}

	evlist->workload.pid = fork();
	if (evlist->workload.pid < 0) {
		perror("failed to fork");
		goto out_close_pipes;
	}

	if (!evlist->workload.pid) {
		if (opts->pipe_output)
			dup2(2, 1);

		close(child_ready_pipe[0]);
		close(go_pipe[1]);
		fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);

		/*
		 * Do a dummy execvp to get the PLT entry resolved,
		 * so we avoid the resolver overhead on the real
		 * execvp call.
		 */
		execvp("", (char **)argv);

		/*
		 * Tell the parent we're ready to go
		 */
		close(child_ready_pipe[1]);

		/*
		 * Wait until the parent tells us to go.
		 */
		if (read(go_pipe[0], &bf, 1) == -1)
			perror("unable to read pipe");

		execvp(argv[0], (char **)argv);

		perror(argv[0]);
		kill(getppid(), SIGUSR1);
		exit(-1);
	}

	if (perf_target__none(target))
		evlist->threads->map[0] = evlist->workload.pid;

	close(child_ready_pipe[1]);
	close(go_pipe[0]);
	/*
	 * wait for child to settle
	 */
	if (read(child_ready_pipe[0], &bf, 1) == -1) {
		perror("unable to read pipe");
		goto out_close_pipes;
	}

	evlist->workload.cork_fd = go_pipe[1];
	close(child_ready_pipe[0]);
	return 0;

out_close_pipes:
	close(go_pipe[0]);
	close(go_pipe[1]);
out_close_ready_pipe:
	close(child_ready_pipe[0]);
	close(child_ready_pipe[1]);
	return -1;
}

int perf_evlist__start_workload(struct perf_evlist *evlist)
{
	if (evlist->workload.cork_fd > 0) {
		/*
		 * Remove the cork, let it rip!
		 */
		return close(evlist->workload.cork_fd);
	}

	return 0;
}

int perf_evlist__parse_sample(struct perf_evlist *evlist, union perf_event *event,
			      struct perf_sample *sample)
{
	struct perf_evsel *evsel = perf_evlist__first(evlist);
	return perf_evsel__parse_sample(evsel, event, sample);
}

size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp)
{
	struct perf_evsel *evsel;
	size_t printed = 0;

	list_for_each_entry(evsel, &evlist->entries, node) {
		printed += fprintf(fp, "%s%s", evsel->idx ? ", " : "",
				   perf_evsel__name(evsel));
	}

	return printed + fprintf(fp, "\n");;
}