2d6121e89ccba5b88ed909322436e5c62e448dfd
[platform/kernel/linux-starfive.git] / tools / lib / perf / evlist.c
1 // SPDX-License-Identifier: GPL-2.0
2 #include <perf/evlist.h>
3 #include <perf/evsel.h>
4 #include <linux/bitops.h>
5 #include <linux/list.h>
6 #include <linux/hash.h>
7 #include <sys/ioctl.h>
8 #include <internal/evlist.h>
9 #include <internal/evsel.h>
10 #include <internal/xyarray.h>
11 #include <internal/mmap.h>
12 #include <internal/cpumap.h>
13 #include <internal/threadmap.h>
14 #include <internal/lib.h>
15 #include <linux/zalloc.h>
16 #include <stdlib.h>
17 #include <errno.h>
18 #include <unistd.h>
19 #include <fcntl.h>
20 #include <signal.h>
21 #include <poll.h>
22 #include <sys/mman.h>
23 #include <perf/cpumap.h>
24 #include <perf/threadmap.h>
25 #include <api/fd/array.h>
26 #include "internal.h"
27
28 void perf_evlist__init(struct perf_evlist *evlist)
29 {
30         INIT_LIST_HEAD(&evlist->entries);
31         evlist->nr_entries = 0;
32         fdarray__init(&evlist->pollfd, 64);
33         perf_evlist__reset_id_hash(evlist);
34 }
35
36 static void __perf_evlist__propagate_maps(struct perf_evlist *evlist,
37                                           struct perf_evsel *evsel)
38 {
39         /*
40          * We already have cpus for evsel (via PMU sysfs) so
41          * keep it, if there's no target cpu list defined.
42          */
43         if (evsel->system_wide) {
44                 perf_cpu_map__put(evsel->cpus);
45                 evsel->cpus = perf_cpu_map__new(NULL);
46         } else if (!evsel->own_cpus || evlist->has_user_cpus ||
47                    (!evsel->requires_cpu && perf_cpu_map__empty(evlist->user_requested_cpus))) {
48                 perf_cpu_map__put(evsel->cpus);
49                 evsel->cpus = perf_cpu_map__get(evlist->user_requested_cpus);
50         } else if (evsel->cpus != evsel->own_cpus) {
51                 perf_cpu_map__put(evsel->cpus);
52                 evsel->cpus = perf_cpu_map__get(evsel->own_cpus);
53         }
54
55         if (evsel->system_wide) {
56                 perf_thread_map__put(evsel->threads);
57                 evsel->threads = perf_thread_map__new_dummy();
58         } else {
59                 perf_thread_map__put(evsel->threads);
60                 evsel->threads = perf_thread_map__get(evlist->threads);
61         }
62
63         evlist->all_cpus = perf_cpu_map__merge(evlist->all_cpus, evsel->cpus);
64 }
65
66 static void perf_evlist__propagate_maps(struct perf_evlist *evlist)
67 {
68         struct perf_evsel *evsel;
69
70         evlist->needs_map_propagation = true;
71
72         perf_evlist__for_each_evsel(evlist, evsel)
73                 __perf_evlist__propagate_maps(evlist, evsel);
74 }
75
76 void perf_evlist__add(struct perf_evlist *evlist,
77                       struct perf_evsel *evsel)
78 {
79         evsel->idx = evlist->nr_entries;
80         list_add_tail(&evsel->node, &evlist->entries);
81         evlist->nr_entries += 1;
82
83         if (evlist->needs_map_propagation)
84                 __perf_evlist__propagate_maps(evlist, evsel);
85 }
86
87 void perf_evlist__remove(struct perf_evlist *evlist,
88                          struct perf_evsel *evsel)
89 {
90         list_del_init(&evsel->node);
91         evlist->nr_entries -= 1;
92 }
93
94 struct perf_evlist *perf_evlist__new(void)
95 {
96         struct perf_evlist *evlist = zalloc(sizeof(*evlist));
97
98         if (evlist != NULL)
99                 perf_evlist__init(evlist);
100
101         return evlist;
102 }
103
104 struct perf_evsel *
105 perf_evlist__next(struct perf_evlist *evlist, struct perf_evsel *prev)
106 {
107         struct perf_evsel *next;
108
109         if (!prev) {
110                 next = list_first_entry(&evlist->entries,
111                                         struct perf_evsel,
112                                         node);
113         } else {
114                 next = list_next_entry(prev, node);
115         }
116
117         /* Empty list is noticed here so don't need checking on entry. */
118         if (&next->node == &evlist->entries)
119                 return NULL;
120
121         return next;
122 }
123
124 static void perf_evlist__purge(struct perf_evlist *evlist)
125 {
126         struct perf_evsel *pos, *n;
127
128         perf_evlist__for_each_entry_safe(evlist, n, pos) {
129                 list_del_init(&pos->node);
130                 perf_evsel__delete(pos);
131         }
132
133         evlist->nr_entries = 0;
134 }
135
136 void perf_evlist__exit(struct perf_evlist *evlist)
137 {
138         perf_cpu_map__put(evlist->user_requested_cpus);
139         perf_cpu_map__put(evlist->all_cpus);
140         perf_thread_map__put(evlist->threads);
141         evlist->user_requested_cpus = NULL;
142         evlist->all_cpus = NULL;
143         evlist->threads = NULL;
144         fdarray__exit(&evlist->pollfd);
145 }
146
147 void perf_evlist__delete(struct perf_evlist *evlist)
148 {
149         if (evlist == NULL)
150                 return;
151
152         perf_evlist__munmap(evlist);
153         perf_evlist__close(evlist);
154         perf_evlist__purge(evlist);
155         perf_evlist__exit(evlist);
156         free(evlist);
157 }
158
159 void perf_evlist__set_maps(struct perf_evlist *evlist,
160                            struct perf_cpu_map *cpus,
161                            struct perf_thread_map *threads)
162 {
163         /*
164          * Allow for the possibility that one or another of the maps isn't being
165          * changed i.e. don't put it.  Note we are assuming the maps that are
166          * being applied are brand new and evlist is taking ownership of the
167          * original reference count of 1.  If that is not the case it is up to
168          * the caller to increase the reference count.
169          */
170         if (cpus != evlist->user_requested_cpus) {
171                 perf_cpu_map__put(evlist->user_requested_cpus);
172                 evlist->user_requested_cpus = perf_cpu_map__get(cpus);
173         }
174
175         if (threads != evlist->threads) {
176                 perf_thread_map__put(evlist->threads);
177                 evlist->threads = perf_thread_map__get(threads);
178         }
179
180         perf_evlist__propagate_maps(evlist);
181 }
182
183 int perf_evlist__open(struct perf_evlist *evlist)
184 {
185         struct perf_evsel *evsel;
186         int err;
187
188         perf_evlist__for_each_entry(evlist, evsel) {
189                 err = perf_evsel__open(evsel, evsel->cpus, evsel->threads);
190                 if (err < 0)
191                         goto out_err;
192         }
193
194         return 0;
195
196 out_err:
197         perf_evlist__close(evlist);
198         return err;
199 }
200
201 void perf_evlist__close(struct perf_evlist *evlist)
202 {
203         struct perf_evsel *evsel;
204
205         perf_evlist__for_each_entry_reverse(evlist, evsel)
206                 perf_evsel__close(evsel);
207 }
208
209 void perf_evlist__enable(struct perf_evlist *evlist)
210 {
211         struct perf_evsel *evsel;
212
213         perf_evlist__for_each_entry(evlist, evsel)
214                 perf_evsel__enable(evsel);
215 }
216
217 void perf_evlist__disable(struct perf_evlist *evlist)
218 {
219         struct perf_evsel *evsel;
220
221         perf_evlist__for_each_entry(evlist, evsel)
222                 perf_evsel__disable(evsel);
223 }
224
225 u64 perf_evlist__read_format(struct perf_evlist *evlist)
226 {
227         struct perf_evsel *first = perf_evlist__first(evlist);
228
229         return first->attr.read_format;
230 }
231
232 #define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
233
234 static void perf_evlist__id_hash(struct perf_evlist *evlist,
235                                  struct perf_evsel *evsel,
236                                  int cpu, int thread, u64 id)
237 {
238         int hash;
239         struct perf_sample_id *sid = SID(evsel, cpu, thread);
240
241         sid->id = id;
242         sid->evsel = evsel;
243         hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
244         hlist_add_head(&sid->node, &evlist->heads[hash]);
245 }
246
247 void perf_evlist__reset_id_hash(struct perf_evlist *evlist)
248 {
249         int i;
250
251         for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
252                 INIT_HLIST_HEAD(&evlist->heads[i]);
253 }
254
255 void perf_evlist__id_add(struct perf_evlist *evlist,
256                          struct perf_evsel *evsel,
257                          int cpu, int thread, u64 id)
258 {
259         perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
260         evsel->id[evsel->ids++] = id;
261 }
262
263 int perf_evlist__id_add_fd(struct perf_evlist *evlist,
264                            struct perf_evsel *evsel,
265                            int cpu, int thread, int fd)
266 {
267         u64 read_data[4] = { 0, };
268         int id_idx = 1; /* The first entry is the counter value */
269         u64 id;
270         int ret;
271
272         ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
273         if (!ret)
274                 goto add;
275
276         if (errno != ENOTTY)
277                 return -1;
278
279         /* Legacy way to get event id.. All hail to old kernels! */
280
281         /*
282          * This way does not work with group format read, so bail
283          * out in that case.
284          */
285         if (perf_evlist__read_format(evlist) & PERF_FORMAT_GROUP)
286                 return -1;
287
288         if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
289             read(fd, &read_data, sizeof(read_data)) == -1)
290                 return -1;
291
292         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
293                 ++id_idx;
294         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
295                 ++id_idx;
296
297         id = read_data[id_idx];
298
299 add:
300         perf_evlist__id_add(evlist, evsel, cpu, thread, id);
301         return 0;
302 }
303
304 int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
305 {
306         int nr_cpus = perf_cpu_map__nr(evlist->all_cpus);
307         int nr_threads = perf_thread_map__nr(evlist->threads);
308         int nfds = 0;
309         struct perf_evsel *evsel;
310
311         perf_evlist__for_each_entry(evlist, evsel) {
312                 if (evsel->system_wide)
313                         nfds += nr_cpus;
314                 else
315                         nfds += nr_cpus * nr_threads;
316         }
317
318         if (fdarray__available_entries(&evlist->pollfd) < nfds &&
319             fdarray__grow(&evlist->pollfd, nfds) < 0)
320                 return -ENOMEM;
321
322         return 0;
323 }
324
325 int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd,
326                             void *ptr, short revent, enum fdarray_flags flags)
327 {
328         int pos = fdarray__add(&evlist->pollfd, fd, revent | POLLERR | POLLHUP, flags);
329
330         if (pos >= 0) {
331                 evlist->pollfd.priv[pos].ptr = ptr;
332                 fcntl(fd, F_SETFL, O_NONBLOCK);
333         }
334
335         return pos;
336 }
337
338 static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd,
339                                          void *arg __maybe_unused)
340 {
341         struct perf_mmap *map = fda->priv[fd].ptr;
342
343         if (map)
344                 perf_mmap__put(map);
345 }
346
347 int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask)
348 {
349         return fdarray__filter(&evlist->pollfd, revents_and_mask,
350                                perf_evlist__munmap_filtered, NULL);
351 }
352
353 int perf_evlist__poll(struct perf_evlist *evlist, int timeout)
354 {
355         return fdarray__poll(&evlist->pollfd, timeout);
356 }
357
358 static struct perf_mmap* perf_evlist__alloc_mmap(struct perf_evlist *evlist, bool overwrite)
359 {
360         int i;
361         struct perf_mmap *map;
362
363         map = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
364         if (!map)
365                 return NULL;
366
367         for (i = 0; i < evlist->nr_mmaps; i++) {
368                 struct perf_mmap *prev = i ? &map[i - 1] : NULL;
369
370                 /*
371                  * When the perf_mmap() call is made we grab one refcount, plus
372                  * one extra to let perf_mmap__consume() get the last
373                  * events after all real references (perf_mmap__get()) are
374                  * dropped.
375                  *
376                  * Each PERF_EVENT_IOC_SET_OUTPUT points to this mmap and
377                  * thus does perf_mmap__get() on it.
378                  */
379                 perf_mmap__init(&map[i], prev, overwrite, NULL);
380         }
381
382         return map;
383 }
384
385 static void perf_evsel__set_sid_idx(struct perf_evsel *evsel, int idx, int cpu, int thread)
386 {
387         struct perf_sample_id *sid = SID(evsel, cpu, thread);
388
389         sid->idx = idx;
390         sid->cpu = perf_cpu_map__cpu(evsel->cpus, cpu);
391         sid->tid = perf_thread_map__pid(evsel->threads, thread);
392 }
393
394 static struct perf_mmap*
395 perf_evlist__mmap_cb_get(struct perf_evlist *evlist, bool overwrite, int idx)
396 {
397         struct perf_mmap *maps;
398
399         maps = overwrite ? evlist->mmap_ovw : evlist->mmap;
400
401         if (!maps) {
402                 maps = perf_evlist__alloc_mmap(evlist, overwrite);
403                 if (!maps)
404                         return NULL;
405
406                 if (overwrite)
407                         evlist->mmap_ovw = maps;
408                 else
409                         evlist->mmap = maps;
410         }
411
412         return &maps[idx];
413 }
414
415 #define FD(e, x, y) (*(int *) xyarray__entry(e->fd, x, y))
416
417 static int
418 perf_evlist__mmap_cb_mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
419                           int output, struct perf_cpu cpu)
420 {
421         return perf_mmap__mmap(map, mp, output, cpu);
422 }
423
424 static void perf_evlist__set_mmap_first(struct perf_evlist *evlist, struct perf_mmap *map,
425                                         bool overwrite)
426 {
427         if (overwrite)
428                 evlist->mmap_ovw_first = map;
429         else
430                 evlist->mmap_first = map;
431 }
432
433 static int
434 mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
435                int idx, struct perf_mmap_param *mp, int cpu_idx,
436                int thread, int *_output, int *_output_overwrite, int *nr_mmaps)
437 {
438         struct perf_cpu evlist_cpu = perf_cpu_map__cpu(evlist->all_cpus, cpu_idx);
439         struct perf_evsel *evsel;
440         int revent;
441
442         perf_evlist__for_each_entry(evlist, evsel) {
443                 bool overwrite = evsel->attr.write_backward;
444                 enum fdarray_flags flgs;
445                 struct perf_mmap *map;
446                 int *output, fd, cpu;
447
448                 if (evsel->system_wide && thread)
449                         continue;
450
451                 cpu = perf_cpu_map__idx(evsel->cpus, evlist_cpu);
452                 if (cpu == -1)
453                         continue;
454
455                 map = ops->get(evlist, overwrite, idx);
456                 if (map == NULL)
457                         return -ENOMEM;
458
459                 if (overwrite) {
460                         mp->prot = PROT_READ;
461                         output   = _output_overwrite;
462                 } else {
463                         mp->prot = PROT_READ | PROT_WRITE;
464                         output   = _output;
465                 }
466
467                 fd = FD(evsel, cpu, thread);
468
469                 if (*output == -1) {
470                         *output = fd;
471
472                         /*
473                          * The last one will be done at perf_mmap__consume(), so that we
474                          * make sure we don't prevent tools from consuming every last event in
475                          * the ring buffer.
476                          *
477                          * I.e. we can get the POLLHUP meaning that the fd doesn't exist
478                          * anymore, but the last events for it are still in the ring buffer,
479                          * waiting to be consumed.
480                          *
481                          * Tools can chose to ignore this at their own discretion, but the
482                          * evlist layer can't just drop it when filtering events in
483                          * perf_evlist__filter_pollfd().
484                          */
485                         refcount_set(&map->refcnt, 2);
486
487                         if (ops->idx)
488                                 ops->idx(evlist, evsel, mp, idx);
489
490                         /* Debug message used by test scripts */
491                         pr_debug("idx %d: mmapping fd %d\n", idx, *output);
492                         if (ops->mmap(map, mp, *output, evlist_cpu) < 0)
493                                 return -1;
494
495                         *nr_mmaps += 1;
496
497                         if (!idx)
498                                 perf_evlist__set_mmap_first(evlist, map, overwrite);
499                 } else {
500                         /* Debug message used by test scripts */
501                         pr_debug("idx %d: set output fd %d -> %d\n", idx, fd, *output);
502                         if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
503                                 return -1;
504
505                         perf_mmap__get(map);
506                 }
507
508                 revent = !overwrite ? POLLIN : 0;
509
510                 flgs = evsel->system_wide ? fdarray_flag__nonfilterable : fdarray_flag__default;
511                 if (perf_evlist__add_pollfd(evlist, fd, map, revent, flgs) < 0) {
512                         perf_mmap__put(map);
513                         return -1;
514                 }
515
516                 if (evsel->attr.read_format & PERF_FORMAT_ID) {
517                         if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
518                                                    fd) < 0)
519                                 return -1;
520                         perf_evsel__set_sid_idx(evsel, idx, cpu, thread);
521                 }
522         }
523
524         return 0;
525 }
526
527 static int
528 mmap_per_thread(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
529                 struct perf_mmap_param *mp)
530 {
531         int nr_threads = perf_thread_map__nr(evlist->threads);
532         int nr_cpus    = perf_cpu_map__nr(evlist->all_cpus);
533         int cpu, thread, idx = 0;
534         int nr_mmaps = 0;
535
536         pr_debug("%s: nr cpu values (may include -1) %d nr threads %d\n",
537                  __func__, nr_cpus, nr_threads);
538
539         /* per-thread mmaps */
540         for (thread = 0; thread < nr_threads; thread++, idx++) {
541                 int output = -1;
542                 int output_overwrite = -1;
543
544                 if (mmap_per_evsel(evlist, ops, idx, mp, 0, thread, &output,
545                                    &output_overwrite, &nr_mmaps))
546                         goto out_unmap;
547         }
548
549         /* system-wide mmaps i.e. per-cpu */
550         for (cpu = 1; cpu < nr_cpus; cpu++, idx++) {
551                 int output = -1;
552                 int output_overwrite = -1;
553
554                 if (mmap_per_evsel(evlist, ops, idx, mp, cpu, 0, &output,
555                                    &output_overwrite, &nr_mmaps))
556                         goto out_unmap;
557         }
558
559         if (nr_mmaps != evlist->nr_mmaps)
560                 pr_err("Miscounted nr_mmaps %d vs %d\n", nr_mmaps, evlist->nr_mmaps);
561
562         return 0;
563
564 out_unmap:
565         perf_evlist__munmap(evlist);
566         return -1;
567 }
568
569 static int
570 mmap_per_cpu(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
571              struct perf_mmap_param *mp)
572 {
573         int nr_threads = perf_thread_map__nr(evlist->threads);
574         int nr_cpus    = perf_cpu_map__nr(evlist->all_cpus);
575         int nr_mmaps = 0;
576         int cpu, thread;
577
578         pr_debug("%s: nr cpu values %d nr threads %d\n", __func__, nr_cpus, nr_threads);
579
580         for (cpu = 0; cpu < nr_cpus; cpu++) {
581                 int output = -1;
582                 int output_overwrite = -1;
583
584                 for (thread = 0; thread < nr_threads; thread++) {
585                         if (mmap_per_evsel(evlist, ops, cpu, mp, cpu,
586                                            thread, &output, &output_overwrite, &nr_mmaps))
587                                 goto out_unmap;
588                 }
589         }
590
591         if (nr_mmaps != evlist->nr_mmaps)
592                 pr_err("Miscounted nr_mmaps %d vs %d\n", nr_mmaps, evlist->nr_mmaps);
593
594         return 0;
595
596 out_unmap:
597         perf_evlist__munmap(evlist);
598         return -1;
599 }
600
601 static int perf_evlist__nr_mmaps(struct perf_evlist *evlist)
602 {
603         int nr_mmaps;
604
605         /* One for each CPU */
606         nr_mmaps = perf_cpu_map__nr(evlist->all_cpus);
607         if (perf_cpu_map__empty(evlist->all_cpus)) {
608                 /* Plus one for each thread */
609                 nr_mmaps += perf_thread_map__nr(evlist->threads);
610                 /* Minus the per-thread CPU (-1) */
611                 nr_mmaps -= 1;
612         }
613
614         return nr_mmaps;
615 }
616
617 int perf_evlist__mmap_ops(struct perf_evlist *evlist,
618                           struct perf_evlist_mmap_ops *ops,
619                           struct perf_mmap_param *mp)
620 {
621         const struct perf_cpu_map *cpus = evlist->all_cpus;
622         struct perf_evsel *evsel;
623
624         if (!ops || !ops->get || !ops->mmap)
625                 return -EINVAL;
626
627         mp->mask = evlist->mmap_len - page_size - 1;
628
629         evlist->nr_mmaps = perf_evlist__nr_mmaps(evlist);
630
631         perf_evlist__for_each_entry(evlist, evsel) {
632                 if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
633                     evsel->sample_id == NULL &&
634                     perf_evsel__alloc_id(evsel, evsel->fd->max_x, evsel->fd->max_y) < 0)
635                         return -ENOMEM;
636         }
637
638         if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
639                 return -ENOMEM;
640
641         if (perf_cpu_map__empty(cpus))
642                 return mmap_per_thread(evlist, ops, mp);
643
644         return mmap_per_cpu(evlist, ops, mp);
645 }
646
647 int perf_evlist__mmap(struct perf_evlist *evlist, int pages)
648 {
649         struct perf_mmap_param mp;
650         struct perf_evlist_mmap_ops ops = {
651                 .get  = perf_evlist__mmap_cb_get,
652                 .mmap = perf_evlist__mmap_cb_mmap,
653         };
654
655         evlist->mmap_len = (pages + 1) * page_size;
656
657         return perf_evlist__mmap_ops(evlist, &ops, &mp);
658 }
659
660 void perf_evlist__munmap(struct perf_evlist *evlist)
661 {
662         int i;
663
664         if (evlist->mmap) {
665                 for (i = 0; i < evlist->nr_mmaps; i++)
666                         perf_mmap__munmap(&evlist->mmap[i]);
667         }
668
669         if (evlist->mmap_ovw) {
670                 for (i = 0; i < evlist->nr_mmaps; i++)
671                         perf_mmap__munmap(&evlist->mmap_ovw[i]);
672         }
673
674         zfree(&evlist->mmap);
675         zfree(&evlist->mmap_ovw);
676 }
677
678 struct perf_mmap*
679 perf_evlist__next_mmap(struct perf_evlist *evlist, struct perf_mmap *map,
680                        bool overwrite)
681 {
682         if (map)
683                 return map->next;
684
685         return overwrite ? evlist->mmap_ovw_first : evlist->mmap_first;
686 }
687
688 void __perf_evlist__set_leader(struct list_head *list, struct perf_evsel *leader)
689 {
690         struct perf_evsel *evsel;
691         int n = 0;
692
693         __perf_evlist__for_each_entry(list, evsel) {
694                 evsel->leader = leader;
695                 n++;
696         }
697         leader->nr_members = n;
698 }
699
700 void perf_evlist__set_leader(struct perf_evlist *evlist)
701 {
702         if (evlist->nr_entries) {
703                 struct perf_evsel *first = list_entry(evlist->entries.next,
704                                                 struct perf_evsel, node);
705
706                 evlist->nr_groups = evlist->nr_entries > 1 ? 1 : 0;
707                 __perf_evlist__set_leader(&evlist->entries, first);
708         }
709 }