text: /*
   * 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 <api/fs/fs.h>
  #include <errno.h>
  #include <inttypes.h>
  #include <poll.h>
  #include "cpumap.h"
  #include "thread_map.h"
  #include "target.h"
  #include "evlist.h"
  #include "evsel.h"
  #include "debug.h"
  #include "units.h"
  #include "asm/bug.h"
  #include <signal.h>
  #include <unistd.h>
  
  #include "parse-events.h"
  #include <subcmd/parse-options.h>
  
  #include <fcntl.h>
  #include <sys/ioctl.h>
  #include <sys/mman.h>
  
  #include <linux/bitops.h>
  #include <linux/hash.h>
  #include <linux/log2.h>
  #include <linux/err.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);
  	fdarray__init(&evlist->pollfd, 64);
  	evlist->workload.pid = -1;
  	evlist->bkw_mmap_state = BKW_MMAP_NOTREADY;
  }
  
  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;
  }
  
  struct perf_evlist *perf_evlist__new_default(void)
  {
  	struct perf_evlist *evlist = perf_evlist__new();
  
  	if (evlist && perf_evlist__add_default(evlist)) {
  		perf_evlist__delete(evlist);
  		evlist = NULL;
  	}
  
  	return evlist;
  }
  
  struct perf_evlist *perf_evlist__new_dummy(void)
  {
  	struct perf_evlist *evlist = perf_evlist__new();
  
  	if (evlist && perf_evlist__add_dummy(evlist)) {
  		perf_evlist__delete(evlist);
  		evlist = NULL;
  	}
  
  	return evlist;
  }
  
  /**
   * perf_evlist__set_id_pos - set the positions of event ids.
   * @evlist: selected event list
   *
   * Events with compatible sample types all have the same id_pos
   * and is_pos.  For convenience, put a copy on evlist.
   */
  void perf_evlist__set_id_pos(struct perf_evlist *evlist)
  {
  	struct perf_evsel *first = perf_evlist__first(evlist);
  
  	evlist->id_pos = first->id_pos;
  	evlist->is_pos = first->is_pos;
  }
  
  static void perf_evlist__update_id_pos(struct perf_evlist *evlist)
  {
  	struct perf_evsel *evsel;
  
  	evlist__for_each_entry(evlist, evsel)
  		perf_evsel__calc_id_pos(evsel);
  
  	perf_evlist__set_id_pos(evlist);
  }
  
  static void perf_evlist__purge(struct perf_evlist *evlist)
  {
  	struct perf_evsel *pos, *n;
  
  	evlist__for_each_entry_safe(evlist, n, pos) {
  		list_del_init(&pos->node);
  		pos->evlist = NULL;
  		perf_evsel__delete(pos);
  	}
  
  	evlist->nr_entries = 0;
  }
  
  void perf_evlist__exit(struct perf_evlist *evlist)
  {
  	zfree(&evlist->mmap);
  	zfree(&evlist->overwrite_mmap);
  	fdarray__exit(&evlist->pollfd);
  }
  
  void perf_evlist__delete(struct perf_evlist *evlist)
  {
  	if (evlist == NULL)
  		return;
  
  	perf_evlist__munmap(evlist);
  	perf_evlist__close(evlist);
  	cpu_map__put(evlist->cpus);
  	thread_map__put(evlist->threads);
  	evlist->cpus = NULL;
  	evlist->threads = NULL;
  	perf_evlist__purge(evlist);
  	perf_evlist__exit(evlist);
  	free(evlist);
  }
  
  static void __perf_evlist__propagate_maps(struct perf_evlist *evlist,
  					  struct perf_evsel *evsel)
  {
  	/*
  	 * We already have cpus for evsel (via PMU sysfs) so
  	 * keep it, if there's no target cpu list defined.
  	 */
  	if (!evsel->own_cpus || evlist->has_user_cpus) {
  		cpu_map__put(evsel->cpus);
  		evsel->cpus = cpu_map__get(evlist->cpus);
  	} else if (evsel->cpus != evsel->own_cpus) {
  		cpu_map__put(evsel->cpus);
  		evsel->cpus = cpu_map__get(evsel->own_cpus);
  	}
  
  	thread_map__put(evsel->threads);
  	evsel->threads = thread_map__get(evlist->threads);
  }
  
  static void perf_evlist__propagate_maps(struct perf_evlist *evlist)
  {
  	struct perf_evsel *evsel;
  
  	evlist__for_each_entry(evlist, evsel)
  		__perf_evlist__propagate_maps(evlist, evsel);
  }
  
  void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry)
  {
  	entry->evlist = evlist;
  	list_add_tail(&entry->node, &evlist->entries);
  	entry->idx = evlist->nr_entries;
  	entry->tracking = !entry->idx;
  
  	if (!evlist->nr_entries++)
  		perf_evlist__set_id_pos(evlist);
  
  	__perf_evlist__propagate_maps(evlist, entry);
  }
  
  void perf_evlist__remove(struct perf_evlist *evlist, struct perf_evsel *evsel)
  {
  	evsel->evlist = NULL;
  	list_del_init(&evsel->node);
  	evlist->nr_entries -= 1;
  }
  
  void perf_evlist__splice_list_tail(struct perf_evlist *evlist,
  				   struct list_head *list)
  {
  	struct perf_evsel *evsel, *temp;
  
  	__evlist__for_each_entry_safe(list, temp, evsel) {
  		list_del_init(&evsel->node);
  		perf_evlist__add(evlist, evsel);
  	}
  }
  
  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;
  
  	__evlist__for_each_entry(list, evsel) {
  		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);
  	}
  }
  
  void perf_event_attr__set_max_precise_ip(struct perf_event_attr *attr)
  {
  	attr->precise_ip = 3;
  
  	while (attr->precise_ip != 0) {
  		int fd = sys_perf_event_open(attr, 0, -1, -1, 0);
  		if (fd != -1) {
  			close(fd);
  			break;
  		}
  		--attr->precise_ip;
  	}
  }
  
  int __perf_evlist__add_default(struct perf_evlist *evlist, bool precise)
  {
  	struct perf_evsel *evsel = perf_evsel__new_cycles(precise);
  
  	if (evsel == NULL)
  		return -ENOMEM;
  
  	perf_evlist__add(evlist, evsel);
  	return 0;
  }
  
  int perf_evlist__add_dummy(struct perf_evlist *evlist)
  {
  	struct perf_event_attr attr = {
  		.type	= PERF_TYPE_SOFTWARE,
  		.config = PERF_COUNT_SW_DUMMY,
  		.size	= sizeof(attr), /* to capture ABI version */
  	};
  	struct perf_evsel *evsel = perf_evsel__new_idx(&attr, evlist->nr_entries);
  
  	if (evsel == NULL)
  		return -ENOMEM;
  
  	perf_evlist__add(evlist, evsel);
  	return 0;
  }
  
  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_idx(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);
  
  	return 0;
  
  out_delete_partial_list:
  	__evlist__for_each_entry_safe(&head, n, evsel)
  		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;
  
  	evlist__for_each_entry(evlist, evsel) {
  		if (evsel->attr.type   == PERF_TYPE_TRACEPOINT &&
  		    (int)evsel->attr.config == id)
  			return evsel;
  	}
  
  	return NULL;
  }
  
  struct perf_evsel *
  perf_evlist__find_tracepoint_by_name(struct perf_evlist *evlist,
  				     const char *name)
  {
  	struct perf_evsel *evsel;
  
  	evlist__for_each_entry(evlist, evsel) {
  		if ((evsel->attr.type == PERF_TYPE_TRACEPOINT) &&
  		    (strcmp(evsel->name, name) == 0))
  			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 = perf_evsel__newtp(sys, name);
  
  	if (IS_ERR(evsel))
  		return -1;
  
  	evsel->handler = handler;
  	perf_evlist__add(evlist, evsel);
  	return 0;
  }
  
  static int perf_evlist__nr_threads(struct perf_evlist *evlist,
  				   struct perf_evsel *evsel)
  {
  	if (evsel->system_wide)
  		return 1;
  	else
  		return thread_map__nr(evlist->threads);
  }
  
  void perf_evlist__disable(struct perf_evlist *evlist)
  {
  	struct perf_evsel *pos;
  
  	evlist__for_each_entry(evlist, pos) {
  		if (pos->disabled || !perf_evsel__is_group_leader(pos) || !pos->fd)
  			continue;
  		perf_evsel__disable(pos);
  	}
  
  	evlist->enabled = false;
  }
  
  void perf_evlist__enable(struct perf_evlist *evlist)
  {
  	struct perf_evsel *pos;
  
  	evlist__for_each_entry(evlist, pos) {
  		if (!perf_evsel__is_group_leader(pos) || !pos->fd)
  			continue;
  		perf_evsel__enable(pos);
  	}
  
  	evlist->enabled = true;
  }
  
  void perf_evlist__toggle_enable(struct perf_evlist *evlist)
  {
  	(evlist->enabled ? perf_evlist__disable : perf_evlist__enable)(evlist);
  }
  
  static int perf_evlist__enable_event_cpu(struct perf_evlist *evlist,
  					 struct perf_evsel *evsel, int cpu)
  {
  	int thread;
  	int nr_threads = perf_evlist__nr_threads(evlist, evsel);
  
  	if (!evsel->fd)
  		return -EINVAL;
  
  	for (thread = 0; thread < nr_threads; thread++) {
  		int err = ioctl(FD(evsel, cpu, thread), PERF_EVENT_IOC_ENABLE, 0);
  		if (err)
  			return err;
  	}
  	return 0;
  }
  
  static int perf_evlist__enable_event_thread(struct perf_evlist *evlist,
  					    struct perf_evsel *evsel,
  					    int thread)
  {
  	int cpu;
  	int nr_cpus = cpu_map__nr(evlist->cpus);
  
  	if (!evsel->fd)
  		return -EINVAL;
  
  	for (cpu = 0; cpu < nr_cpus; cpu++) {
  		int err = ioctl(FD(evsel, cpu, thread), PERF_EVENT_IOC_ENABLE, 0);
  		if (err)
  			return err;
  	}
  	return 0;
  }
  
  int perf_evlist__enable_event_idx(struct perf_evlist *evlist,
  				  struct perf_evsel *evsel, int idx)
  {
  	bool per_cpu_mmaps = !cpu_map__empty(evlist->cpus);
  
  	if (per_cpu_mmaps)
  		return perf_evlist__enable_event_cpu(evlist, evsel, idx);
  	else
  		return perf_evlist__enable_event_thread(evlist, evsel, idx);
  }
  
  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 = 0;
  	struct perf_evsel *evsel;
  
  	evlist__for_each_entry(evlist, evsel) {
  		if (evsel->system_wide)
  			nfds += nr_cpus;
  		else
  			nfds += nr_cpus * nr_threads;
  	}
  
  	if (fdarray__available_entries(&evlist->pollfd) < nfds &&
  	    fdarray__grow(&evlist->pollfd, nfds) < 0)
  		return -ENOMEM;
  
  	return 0;
  }
  
  static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd,
  				     struct perf_mmap *map, short revent)
  {
  	int pos = fdarray__add(&evlist->pollfd, fd, revent | POLLERR | POLLHUP);
  	/*
  	 * Save the idx so that when we filter out fds POLLHUP'ed we can
  	 * close the associated evlist->mmap[] entry.
  	 */
  	if (pos >= 0) {
  		evlist->pollfd.priv[pos].ptr = map;
  
  		fcntl(fd, F_SETFL, O_NONBLOCK);
  	}
  
  	return pos;
  }
  
  int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
  {
  	return __perf_evlist__add_pollfd(evlist, fd, NULL, POLLIN);
  }
  
  static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd,
  					 void *arg __maybe_unused)
  {
  	struct perf_mmap *map = fda->priv[fd].ptr;
  
  	if (map)
  		perf_mmap__put(map);
  }
  
  int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask)
  {
  	return fdarray__filter(&evlist->pollfd, revents_and_mask,
  			       perf_evlist__munmap_filtered, NULL);
  }
  
  int perf_evlist__poll(struct perf_evlist *evlist, int timeout)
  {
  	return fdarray__poll(&evlist->pollfd, timeout);
  }
  
  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;
  }
  
  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 */
  	u64 id;
  	int ret;
  
  	ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
  	if (!ret)
  		goto add;
  
  	if (errno != ENOTTY)
  		return -1;
  
  	/* Legacy way to get event id.. All hail to old kernels! */
  
  	/*
  	 * This way does not work with group format read, so bail
  	 * out in that case.
  	 */
  	if (perf_evlist__read_format(evlist) & PERF_FORMAT_GROUP)
  		return -1;
  
  	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;
  
  	id = read_data[id_idx];
  
   add:
  	perf_evlist__id_add(evlist, evsel, cpu, thread, id);
  	return 0;
  }
  
  static void perf_evlist__set_sid_idx(struct perf_evlist *evlist,
  				     struct perf_evsel *evsel, int idx, int cpu,
  				     int thread)
  {
  	struct perf_sample_id *sid = SID(evsel, cpu, thread);
  	sid->idx = idx;
  	if (evlist->cpus && cpu >= 0)
  		sid->cpu = evlist->cpus->map[cpu];
  	else
  		sid->cpu = -1;
  	if (!evsel->system_wide && evlist->threads && thread >= 0)
  		sid->tid = thread_map__pid(evlist->threads, thread);
  	else
  		sid->tid = -1;
  }
  
  struct perf_sample_id *perf_evlist__id2sid(struct perf_evlist *evlist, u64 id)
  {
  	struct hlist_head *head;
  	struct perf_sample_id *sid;
  	int hash;
  
  	hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
  	head = &evlist->heads[hash];
  
  	hlist_for_each_entry(sid, head, node)
  		if (sid->id == id)
  			return sid;
  
  	return NULL;
  }
  
  struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
  {
  	struct perf_sample_id *sid;
  
  	if (evlist->nr_entries == 1 || !id)
  		return perf_evlist__first(evlist);
  
  	sid = perf_evlist__id2sid(evlist, id);
  	if (sid)
  		return sid->evsel;
  
  	if (!perf_evlist__sample_id_all(evlist))
  		return perf_evlist__first(evlist);
  
  	return NULL;
  }
  
  struct perf_evsel *perf_evlist__id2evsel_strict(struct perf_evlist *evlist,
  						u64 id)
  {
  	struct perf_sample_id *sid;
  
  	if (!id)
  		return NULL;
  
  	sid = perf_evlist__id2sid(evlist, id);
  	if (sid)
  		return sid->evsel;
  
  	return NULL;
  }
  
  static int perf_evlist__event2id(struct perf_evlist *evlist,
  				 union perf_event *event, u64 *id)
  {
  	const u64 *array = event->sample.array;
  	ssize_t n;
  
  	n = (event->header.size - sizeof(event->header)) >> 3;
  
  	if (event->header.type == PERF_RECORD_SAMPLE) {
  		if (evlist->id_pos >= n)
  			return -1;
  		*id = array[evlist->id_pos];
  	} else {
  		if (evlist->is_pos > n)
  			return -1;
  		n -= evlist->is_pos;
  		*id = array[n];
  	}
  	return 0;
  }
  
  struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist,
  					    union perf_event *event)
  {
  	struct perf_evsel *first = perf_evlist__first(evlist);
  	struct hlist_head *head;
  	struct perf_sample_id *sid;
  	int hash;
  	u64 id;
  
  	if (evlist->nr_entries == 1)
  		return first;
  
  	if (!first->attr.sample_id_all &&
  	    event->header.type != PERF_RECORD_SAMPLE)
  		return first;
  
  	if (perf_evlist__event2id(evlist, event, &id))
  		return NULL;
  
  	/* Synthesized events have an id of zero */
  	if (!id)
  		return first;
  
  	hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
  	head = &evlist->heads[hash];
  
  	hlist_for_each_entry(sid, head, node) {
  		if (sid->id == id)
  			return sid->evsel;
  	}
  	return NULL;
  }
  
  static int perf_evlist__set_paused(struct perf_evlist *evlist, bool value)
  {
  	int i;
  
  	if (!evlist->overwrite_mmap)
  		return 0;
  
  	for (i = 0; i < evlist->nr_mmaps; i++) {
  		int fd = evlist->overwrite_mmap[i].fd;
  		int err;
  
  		if (fd < 0)
  			continue;
  		err = ioctl(fd, PERF_EVENT_IOC_PAUSE_OUTPUT, value ? 1 : 0);
  		if (err)
  			return err;
  	}
  	return 0;
  }
  
  static int perf_evlist__pause(struct perf_evlist *evlist)
  {
  	return perf_evlist__set_paused(evlist, true);
  }
  
  static int perf_evlist__resume(struct perf_evlist *evlist)
  {
  	return perf_evlist__set_paused(evlist, false);
  }
  
  static void perf_evlist__munmap_nofree(struct perf_evlist *evlist)
  {
  	int i;
  
  	if (evlist->mmap)
  		for (i = 0; i < evlist->nr_mmaps; i++)
  			perf_mmap__munmap(&evlist->mmap[i]);
  
  	if (evlist->overwrite_mmap)
  		for (i = 0; i < evlist->nr_mmaps; i++)
  			perf_mmap__munmap(&evlist->overwrite_mmap[i]);
  }
  
  void perf_evlist__munmap(struct perf_evlist *evlist)
  {
  	perf_evlist__munmap_nofree(evlist);
  	zfree(&evlist->mmap);
  	zfree(&evlist->overwrite_mmap);
  }
  
  static struct perf_mmap *perf_evlist__alloc_mmap(struct perf_evlist *evlist,
  						 bool overwrite)
  {
  	int i;
  	struct perf_mmap *map;
  
  	evlist->nr_mmaps = cpu_map__nr(evlist->cpus);
  	if (cpu_map__empty(evlist->cpus))
  		evlist->nr_mmaps = thread_map__nr(evlist->threads);
  	map = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
  	if (!map)
  		return NULL;
  
  	for (i = 0; i < evlist->nr_mmaps; i++) {
  		map[i].fd = -1;
  		map[i].overwrite = overwrite;
  		/*
  		 * When the perf_mmap() call is made we grab one refcount, plus
  		 * one extra to let perf_mmap__consume() get the last
  		 * events after all real references (perf_mmap__get()) are
  		 * dropped.
  		 *
  		 * Each PERF_EVENT_IOC_SET_OUTPUT points to this mmap and
  		 * thus does perf_mmap__get() on it.
  		 */
  		refcount_set(&map[i].refcnt, 0);
  	}
  	return map;
  }
  
  static bool
  perf_evlist__should_poll(struct perf_evlist *evlist __maybe_unused,
  			 struct perf_evsel *evsel)
  {
  	if (evsel->attr.write_backward)
  		return false;
  	return true;
  }
  
  static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
  				       struct mmap_params *mp, int cpu_idx,
  				       int thread, int *_output, int *_output_overwrite)
  {
  	struct perf_evsel *evsel;
  	int revent;
  	int evlist_cpu = cpu_map__cpu(evlist->cpus, cpu_idx);
  
  	evlist__for_each_entry(evlist, evsel) {
  		struct perf_mmap *maps = evlist->mmap;
  		int *output = _output;
  		int fd;
  		int cpu;
  
  		mp->prot = PROT_READ | PROT_WRITE;
  		if (evsel->attr.write_backward) {
  			output = _output_overwrite;
  			maps = evlist->overwrite_mmap;
  
  			if (!maps) {
  				maps = perf_evlist__alloc_mmap(evlist, true);
  				if (!maps)
  					return -1;
  				evlist->overwrite_mmap = maps;
  				if (evlist->bkw_mmap_state == BKW_MMAP_NOTREADY)
  					perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_RUNNING);
  			}
  			mp->prot &= ~PROT_WRITE;
  		}
  
  		if (evsel->system_wide && thread)
  			continue;
  
  		cpu = cpu_map__idx(evsel->cpus, evlist_cpu);
  		if (cpu == -1)
  			continue;
  
  		fd = FD(evsel, cpu, thread);
  
  		if (*output == -1) {
  			*output = fd;
  
  			if (perf_mmap__mmap(&maps[idx], mp, *output, evlist_cpu) < 0)
  				return -1;
  		} else {
  			if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
  				return -1;
  
  			perf_mmap__get(&maps[idx]);
  		}
  
  		revent = perf_evlist__should_poll(evlist, evsel) ? POLLIN : 0;
  
  		/*
  		 * The system_wide flag causes a selected event to be opened
  		 * always without a pid.  Consequently it will never get a
  		 * POLLHUP, but it is used for tracking in combination with
  		 * other events, so it should not need to be polled anyway.
  		 * Therefore don't add it for polling.
  		 */
  		if (!evsel->system_wide &&
  		    __perf_evlist__add_pollfd(evlist, fd, &maps[idx], revent) < 0) {
  			perf_mmap__put(&maps[idx]);
  			return -1;
  		}
  
  		if (evsel->attr.read_format & PERF_FORMAT_ID) {
  			if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
  						   fd) < 0)
  				return -1;
  			perf_evlist__set_sid_idx(evlist, evsel, idx, cpu,
  						 thread);
  		}
  	}
  
  	return 0;
  }
  
  static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist,
  				     struct mmap_params *mp)
  {
  	int cpu, thread;
  	int nr_cpus = cpu_map__nr(evlist->cpus);
  	int nr_threads = thread_map__nr(evlist->threads);
  
  	pr_debug2("perf event ring buffer mmapped per cpu\n");
  	for (cpu = 0; cpu < nr_cpus; cpu++) {
  		int output = -1;
  		int output_overwrite = -1;
  
  		auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist, cpu,
  					      true);
  
  		for (thread = 0; thread < nr_threads; thread++) {
  			if (perf_evlist__mmap_per_evsel(evlist, cpu, mp, cpu,
  							thread, &output, &output_overwrite))
  				goto out_unmap;
  		}
  	}
  
  	return 0;
  
  out_unmap:
  	perf_evlist__munmap_nofree(evlist);
  	return -1;
  }
  
  static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist,
  					struct mmap_params *mp)
  {
  	int thread;
  	int nr_threads = thread_map__nr(evlist->threads);
  
  	pr_debug2("perf event ring buffer mmapped per thread\n");
  	for (thread = 0; thread < nr_threads; thread++) {
  		int output = -1;
  		int output_overwrite = -1;
  
  		auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist, thread,
  					      false);
  
  		if (perf_evlist__mmap_per_evsel(evlist, thread, mp, 0, thread,
  						&output, &output_overwrite))
  			goto out_unmap;
  	}
  
  	return 0;
  
  out_unmap:
  	perf_evlist__munmap_nofree(evlist);
  	return -1;
  }
  
  unsigned long perf_event_mlock_kb_in_pages(void)
  {
  	unsigned long pages;
  	int max;
  
  	if (sysctl__read_int("kernel/perf_event_mlock_kb", &max) < 0) {
  		/*
  		 * Pick a once upon a time good value, i.e. things look
  		 * strange since we can't read a sysctl value, but lets not
  		 * die yet...
  		 */
  		max = 512;
  	} else {
  		max -= (page_size / 1024);
  	}
  
  	pages = (max * 1024) / page_size;
  	if (!is_power_of_2(pages))
  		pages = rounddown_pow_of_two(pages);
  
  	return pages;
  }
  
  size_t perf_evlist__mmap_size(unsigned long pages)
  {
  	if (pages == UINT_MAX)
  		pages = perf_event_mlock_kb_in_pages();
  	else if (!is_power_of_2(pages))
  		return 0;
  
  	return (pages + 1) * page_size;
  }
  
  static long parse_pages_arg(const char *str, unsigned long min,
  			    unsigned long max)
  {
  	unsigned long pages, val;
  	static struct parse_tag tags[] = {
  		{ .tag  = 'B', .mult = 1       },
  		{ .tag  = 'K', .mult = 1 << 10 },
  		{ .tag  = 'M', .mult = 1 << 20 },
  		{ .tag  = 'G', .mult = 1 << 30 },
  		{ .tag  = 0 },
  	};
  
  	if (str == NULL)
  		return -EINVAL;
  
  	val = parse_tag_value(str, tags);
  	if (val != (unsigned long) -1) {
  		/* we got file size value */
  		pages = PERF_ALIGN(val, page_size) / page_size;
  	} else {
  		/* we got pages count value */
  		char *eptr;
  		pages = strtoul(str, &eptr, 10);
  		if (*eptr != '\0')
  			return -EINVAL;
  	}
  
  	if (pages == 0 && min == 0) {
  		/* leave number of pages at 0 */
  	} else if (!is_power_of_2(pages)) {
  		char buf[100];
  
  		/* round pages up to next power of 2 */
  		pages = roundup_pow_of_two(pages);
  		if (!pages)
  			return -EINVAL;
  
  		unit_number__scnprintf(buf, sizeof(buf), pages * page_size);
  		pr_info("rounding mmap pages size to %s (%lu pages)\n",
  			buf, pages);
  	}
  
  	if (pages > max)
  		return -EINVAL;
  
  	return pages;
  }
  
  int __perf_evlist__parse_mmap_pages(unsigned int *mmap_pages, const char *str)
  {
  	unsigned long max = UINT_MAX;
  	long pages;
  
  	if (max > SIZE_MAX / page_size)
  		max = SIZE_MAX / page_size;
  
  	pages = parse_pages_arg(str, 1, max);
  	if (pages < 0) {
  		pr_err("Invalid argument for --mmap_pages/-m\n");
  		return -1;
  	}
  
  	*mmap_pages = pages;
  	return 0;
  }
  
  int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
  				  int unset __maybe_unused)
  {
  	return __perf_evlist__parse_mmap_pages(opt->value, str);
  }
  
  /**
   * perf_evlist__mmap_ex - Create mmaps to receive events.
   * @evlist: list of events
   * @pages: map length in pages
   * @overwrite: overwrite older events?
   * @auxtrace_pages - auxtrace map length in pages
   * @auxtrace_overwrite - overwrite older auxtrace data?
   *
   * If @overwrite is %false the user needs to signal event consumption using
   * perf_mmap__write_tail().  Using perf_evlist__mmap_read() does this
   * automatically.
   *
   * Similarly, if @auxtrace_overwrite is %false the user needs to signal data
   * consumption using auxtrace_mmap__write_tail().
   *
   * Return: %0 on success, negative error code otherwise.
   */
  int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
  			 unsigned int auxtrace_pages,
  			 bool auxtrace_overwrite)
  {
  	struct perf_evsel *evsel;
  	const struct cpu_map *cpus = evlist->cpus;
  	const struct thread_map *threads = evlist->threads;
  	/*
  	 * Delay setting mp.prot: set it before calling perf_mmap__mmap.
  	 * Its value is decided by evsel's write_backward.
  	 * So &mp should not be passed through const pointer.
  	 */
  	struct mmap_params mp;
  
  	if (!evlist->mmap)
  		evlist->mmap = perf_evlist__alloc_mmap(evlist, false);
  	if (!evlist->mmap)
  		return -ENOMEM;
  
  	if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
  		return -ENOMEM;
  
  	evlist->mmap_len = perf_evlist__mmap_size(pages);
  	pr_debug("mmap size %zuB\n", evlist->mmap_len);
  	mp.mask = evlist->mmap_len - page_size - 1;
  
  	auxtrace_mmap_params__init(&mp.auxtrace_mp, evlist->mmap_len,
  				   auxtrace_pages, auxtrace_overwrite);
  
  	evlist__for_each_entry(evlist, evsel) {
  		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__empty(cpus))
  		return perf_evlist__mmap_per_thread(evlist, &mp);
  
  	return perf_evlist__mmap_per_cpu(evlist, &mp);
  }
  
  int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages)
  {
  	return perf_evlist__mmap_ex(evlist, pages, 0, false);
  }
  
  int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
  {
  	bool all_threads = (target->per_thread && target->system_wide);
  	struct cpu_map *cpus;
  	struct thread_map *threads;
  
  	/*
  	 * If specify '-a' and '--per-thread' to perf record, perf record
  	 * will override '--per-thread'. target->per_thread = false and
  	 * target->system_wide = true.
  	 *
  	 * If specify '--per-thread' only to perf record,
  	 * target->per_thread = true and target->system_wide = false.
  	 *
  	 * So target->per_thread && target->system_wide is false.
  	 * For perf record, thread_map__new_str doesn't call
  	 * thread_map__new_all_cpus. That will keep perf record's
  	 * current behavior.
  	 *
  	 * For perf stat, it allows the case that target->per_thread and
  	 * target->system_wide are all true. It means to collect system-wide
  	 * per-thread data. thread_map__new_str will call
  	 * thread_map__new_all_cpus to enumerate all threads.
  	 */
  	threads = thread_map__new_str(target->pid, target->tid, target->uid,
  				      all_threads);
  
  	if (!threads)
  		return -1;
  
  	if (target__uses_dummy_map(target))
  		cpus = cpu_map__dummy_new();
  	else
  		cpus = cpu_map__new(target->cpu_list);
  
  	if (!cpus)
  		goto out_delete_threads;
  
  	evlist->has_user_cpus = !!target->cpu_list;
  
  	perf_evlist__set_maps(evlist, cpus, threads);
  
  	return 0;
  
  out_delete_threads:
  	thread_map__put(threads);
  	return -1;
  }
  
  void perf_evlist__set_maps(struct perf_evlist *evlist, struct cpu_map *cpus,
  			   struct thread_map *threads)
  {
  	/*
  	 * Allow for the possibility that one or another of the maps isn't being
  	 * changed i.e. don't put it.  Note we are assuming the maps that are
  	 * being applied are brand new and evlist is taking ownership of the
  	 * original reference count of 1.  If that is not the case it is up to
  	 * the caller to increase the reference count.
  	 */
  	if (cpus != evlist->cpus) {
  		cpu_map__put(evlist->cpus);
  		evlist->cpus = cpu_map__get(cpus);
  	}
  
  	if (threads != evlist->threads) {
  		thread_map__put(evlist->threads);
  		evlist->threads = thread_map__get(threads);
  	}
  
  	perf_evlist__propagate_maps(evlist);
  }
  
  void __perf_evlist__set_sample_bit(struct perf_evlist *evlist,
  				   enum perf_event_sample_format bit)
  {
  	struct perf_evsel *evsel;
  
  	evlist__for_each_entry(evlist, evsel)
  		__perf_evsel__set_sample_bit(evsel, bit);
  }
  
  void __perf_evlist__reset_sample_bit(struct perf_evlist *evlist,
  				     enum perf_event_sample_format bit)
  {
  	struct perf_evsel *evsel;
  
  	evlist__for_each_entry(evlist, evsel)
  		__perf_evsel__reset_sample_bit(evsel, bit);
  }
  
  int perf_evlist__apply_filters(struct perf_evlist *evlist, struct perf_evsel **err_evsel)
  {
  	struct perf_evsel *evsel;
  	int err = 0;
  
  	evlist__for_each_entry(evlist, evsel) {
  		if (evsel->filter == NULL)
  			continue;
  
  		/*
  		 * filters only work for tracepoint event, which doesn't have cpu limit.
  		 * So evlist and evsel should always be same.
  		 */
  		err = perf_evsel__apply_filter(evsel, evsel->filter);
  		if (err) {
  			*err_evsel = evsel;
  			break;
  		}
  	}
  
  	return err;
  }
  
  int perf_evlist__set_filter(struct perf_evlist *evlist, const char *filter)
  {
  	struct perf_evsel *evsel;
  	int err = 0;
  
  	evlist__for_each_entry(evlist, evsel) {
  		if (evsel->attr.type != PERF_TYPE_TRACEPOINT)
  			continue;
  
  		err = perf_evsel__set_filter(evsel, filter);
  		if (err)
  			break;
  	}
  
  	return err;
  }
  
  int perf_evlist__set_filter_pids(struct perf_evlist *evlist, size_t npids, pid_t *pids)
  {
  	char *filter;
  	int ret = -1;
  	size_t i;
  
  	for (i = 0; i < npids; ++i) {
  		if (i == 0) {
  			if (asprintf(&filter, "common_pid != %d", pids[i]) < 0)
  				return -1;
  		} else {
  			char *tmp;
  
  			if (asprintf(&tmp, "%s && common_pid != %d", filter, pids[i]) < 0)
  				goto out_free;
  
  			free(filter);
  			filter = tmp;
  		}
  	}
  
  	ret = perf_evlist__set_filter(evlist, filter);
  out_free:
  	free(filter);
  	return ret;
  }
  
  int perf_evlist__set_filter_pid(struct perf_evlist *evlist, pid_t pid)
  {
  	return perf_evlist__set_filter_pids(evlist, 1, &pid);
  }
  
  bool perf_evlist__valid_sample_type(struct perf_evlist *evlist)
  {
  	struct perf_evsel *pos;
  
  	if (evlist->nr_entries == 1)
  		return true;
  
  	if (evlist->id_pos < 0 || evlist->is_pos < 0)
  		return false;
  
  	evlist__for_each_entry(evlist, pos) {
  		if (pos->id_pos != evlist->id_pos ||
  		    pos->is_pos != evlist->is_pos)
  			return false;
  	}
  
  	return true;
  }
  
  u64 __perf_evlist__combined_sample_type(struct perf_evlist *evlist)
  {
  	struct perf_evsel *evsel;
  
  	if (evlist->combined_sample_type)
  		return evlist->combined_sample_type;
  
  	evlist__for_each_entry(evlist, evsel)
  		evlist->combined_sample_type |= evsel->attr.sample_type;
  
  	return evlist->combined_sample_type;
  }
  
  u64 perf_evlist__combined_sample_type(struct perf_evlist *evlist)
  {
  	evlist->combined_sample_type = 0;
  	return __perf_evlist__combined_sample_type(evlist);
  }
  
  u64 perf_evlist__combined_branch_type(struct perf_evlist *evlist)
  {
  	struct perf_evsel *evsel;
  	u64 branch_type = 0;
  
  	evlist__for_each_entry(evlist, evsel)
  		branch_type |= evsel->attr.branch_sample_type;
  	return branch_type;
  }
  
  bool perf_evlist__valid_read_format(struct perf_evlist *evlist)
  {
  	struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;
  	u64 read_format = first->attr.read_format;
  	u64 sample_type = first->attr.sample_type;
  
  	evlist__for_each_entry(evlist, pos) {
  		if (read_format != pos->attr.read_format)
  			return false;
  	}
  
  	/* PERF_SAMPLE_READ imples PERF_FORMAT_ID. */
  	if ((sample_type & PERF_SAMPLE_READ) &&
  	    !(read_format & PERF_FORMAT_ID)) {
  		return false;
  	}
  
  	return true;
  }
  
  u64 perf_evlist__read_format(struct perf_evlist *evlist)
  {
  	struct perf_evsel *first = perf_evlist__first(evlist);
  	return first->attr.read_format;
  }
  
  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;
  
  	if (sample_type & PERF_SAMPLE_IDENTIFIER)
  		size += sizeof(data->id);
  out:
  	return size;
  }
  
  bool perf_evlist__valid_sample_id_all(struct perf_evlist *evlist)
  {
  	struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;
  
  	evlist__for_each_entry_continue(evlist, pos) {
  		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;
  }
  
  void perf_evlist__close(struct perf_evlist *evlist)
  {
  	struct perf_evsel *evsel;
  
  	evlist__for_each_entry_reverse(evlist, evsel)
  		perf_evsel__close(evsel);
  }
  
  static int perf_evlist__create_syswide_maps(struct perf_evlist *evlist)
  {
  	struct cpu_map	  *cpus;
  	struct thread_map *threads;
  	int err = -ENOMEM;
  
  	/*
  	 * Try reading /sys/devices/system/cpu/online to get
  	 * an all cpus map.
  	 *
  	 * FIXME: -ENOMEM is the best we can do here, the cpu_map
  	 * code needs an overhaul to properly forward the
  	 * error, and we may not want to do that fallback to a
  	 * default cpu identity map :-\
  	 */
  	cpus = cpu_map__new(NULL);
  	if (!cpus)
  		goto out;
  
  	threads = thread_map__new_dummy();
  	if (!threads)
  		goto out_put;
  
  	perf_evlist__set_maps(evlist, cpus, threads);
  out:
  	return err;
  out_put:
  	cpu_map__put(cpus);
  	goto out;
  }
  
  int perf_evlist__open(struct perf_evlist *evlist)
  {
  	struct perf_evsel *evsel;
  	int err;
  
  	/*
  	 * Default: one fd per CPU, all threads, aka systemwide
  	 * as sys_perf_event_open(cpu = -1, thread = -1) is EINVAL
  	 */
  	if (evlist->threads == NULL && evlist->cpus == NULL) {
  		err = perf_evlist__create_syswide_maps(evlist);
  		if (err < 0)
  			goto out_err;
  	}
  
  	perf_evlist__update_id_pos(evlist);
  
  	evlist__for_each_entry(evlist, evsel) {
  		err = perf_evsel__open(evsel, evsel->cpus, evsel->threads);
  		if (err < 0)
  			goto out_err;
  	}
  
  	return 0;
  out_err:
  	perf_evlist__close(evlist);
  	errno = -err;
  	return err;
  }
  
  int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct target *target,
  				  const char *argv[], bool pipe_output,
  				  void (*exec_error)(int signo, siginfo_t *info, void *ucontext))
  {
  	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) {
  		int ret;
  
  		if (pipe_output)
  			dup2(2, 1);
  
  		signal(SIGTERM, SIG_DFL);
  
  		close(child_ready_pipe[0]);
  		close(go_pipe[1]);
  		fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
  
  		/*
  		 * Tell the parent we're ready to go
  		 */
  		close(child_ready_pipe[1]);
  
  		/*
  		 * Wait until the parent tells us to go.
  		 */
  		ret = read(go_pipe[0], &bf, 1);
  		/*
  		 * The parent will ask for the execvp() to be performed by
  		 * writing exactly one byte, in workload.cork_fd, usually via
  		 * perf_evlist__start_workload().
  		 *
  		 * For cancelling the workload without actually running it,
  		 * the parent will just close workload.cork_fd, without writing
  		 * anything, i.e. read will return zero and we just exit()
  		 * here.
  		 */
  		if (ret != 1) {
  			if (ret == -1)
  				perror("unable to read pipe");
  			exit(ret);
  		}
  
  		execvp(argv[0], (char **)argv);
  
  		if (exec_error) {
  			union sigval val;
  
  			val.sival_int = errno;
  			if (sigqueue(getppid(), SIGUSR1, val))
  				perror(argv[0]);
  		} else
  			perror(argv[0]);
  		exit(-1);
  	}
  
  	if (exec_error) {
  		struct sigaction act = {
  			.sa_flags     = SA_SIGINFO,
  			.sa_sigaction = exec_error,
  		};
  		sigaction(SIGUSR1, &act, NULL);
  	}
  
  	if (target__none(target)) {
  		if (evlist->threads == NULL) {
  			fprintf(stderr, "FATAL: evlist->threads need to be set at this point (%s:%d).\n",
  				__func__, __LINE__);
  			goto out_close_pipes;
  		}
  		thread_map__set_pid(evlist->threads, 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;
  	}
  
  	fcntl(go_pipe[1], F_SETFD, FD_CLOEXEC);
  	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) {
  		char bf = 0;
  		int ret;
  		/*
  		 * Remove the cork, let it rip!
  		 */
  		ret = write(evlist->workload.cork_fd, &bf, 1);
  		if (ret < 0)
  			perror("unable to write to pipe");
  
  		close(evlist->workload.cork_fd);
  		return ret;
  	}
  
  	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__event2evsel(evlist, event);
  
  	if (!evsel)
  		return -EFAULT;
  	return perf_evsel__parse_sample(evsel, event, sample);
  }
  
  int perf_evlist__parse_sample_timestamp(struct perf_evlist *evlist,
  					union perf_event *event,
  					u64 *timestamp)
  {
  	struct perf_evsel *evsel = perf_evlist__event2evsel(evlist, event);
  
  	if (!evsel)
  		return -EFAULT;
  	return perf_evsel__parse_sample_timestamp(evsel, event, timestamp);
  }
  
  size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp)
  {
  	struct perf_evsel *evsel;
  	size_t printed = 0;
  
  	evlist__for_each_entry(evlist, evsel) {
  		printed += fprintf(fp, "%s%s", evsel->idx ? ", " : "",
  				   perf_evsel__name(evsel));
  	}
  
  	return printed + fprintf(fp, "\n");
  }
  
  int perf_evlist__strerror_open(struct perf_evlist *evlist,
  			       int err, char *buf, size_t size)
  {
  	int printed, value;
  	char sbuf[STRERR_BUFSIZE], *emsg = str_error_r(err, sbuf, sizeof(sbuf));
  
  	switch (err) {
  	case EACCES:
  	case EPERM:
  		printed = scnprintf(buf, size,
  				    "Error:\t%s.\n"
  				    "Hint:\tCheck /proc/sys/kernel/perf_event_paranoid setting.", emsg);
  
  		value = perf_event_paranoid();
  
  		printed += scnprintf(buf + printed, size - printed, "\nHint:\t");
  
  		if (value >= 2) {
  			printed += scnprintf(buf + printed, size - printed,
  					     "For your workloads it needs to be <= 1\nHint:\t");
  		}
  		printed += scnprintf(buf + printed, size - printed,
  				     "For system wide tracing it needs to be set to -1.\n");
  
  		printed += scnprintf(buf + printed, size - printed,
  				    "Hint:\tTry: 'sudo sh -c \"echo -1 > /proc/sys/kernel/perf_event_paranoid\"'\n"
  				    "Hint:\tThe current value is %d.", value);
  		break;
  	case EINVAL: {
  		struct perf_evsel *first = perf_evlist__first(evlist);
  		int max_freq;
  
  		if (sysctl__read_int("kernel/perf_event_max_sample_rate", &max_freq) < 0)
  			goto out_default;
  
  		if (first->attr.sample_freq < (u64)max_freq)
  			goto out_default;
  
  		printed = scnprintf(buf, size,
  				    "Error:\t%s.\n"
  				    "Hint:\tCheck /proc/sys/kernel/perf_event_max_sample_rate.\n"
  				    "Hint:\tThe current value is %d and %" PRIu64 " is being requested.",
  				    emsg, max_freq, first->attr.sample_freq);
  		break;
  	}
  	default:
  out_default:
  		scnprintf(buf, size, "%s", emsg);
  		break;
  	}
  
  	return 0;
  }
  
  int perf_evlist__strerror_mmap(struct perf_evlist *evlist, int err, char *buf, size_t size)
  {
  	char sbuf[STRERR_BUFSIZE], *emsg = str_error_r(err, sbuf, sizeof(sbuf));
  	int pages_attempted = evlist->mmap_len / 1024, pages_max_per_user, printed = 0;
  
  	switch (err) {
  	case EPERM:
  		sysctl__read_int("kernel/perf_event_mlock_kb", &pages_max_per_user);
  		printed += scnprintf(buf + printed, size - printed,
  				     "Error:\t%s.\n"
  				     "Hint:\tCheck /proc/sys/kernel/perf_event_mlock_kb (%d kB) setting.\n"
  				     "Hint:\tTried using %zd kB.\n",
  				     emsg, pages_max_per_user, pages_attempted);
  
  		if (pages_attempted >= pages_max_per_user) {
  			printed += scnprintf(buf + printed, size - printed,
  					     "Hint:\tTry 'sudo sh -c \"echo %d > /proc/sys/kernel/perf_event_mlock_kb\"', or\n",
  					     pages_max_per_user + pages_attempted);
  		}
  
  		printed += scnprintf(buf + printed, size - printed,
  				     "Hint:\tTry using a smaller -m/--mmap-pages value.");
  		break;
  	default:
  		scnprintf(buf, size, "%s", emsg);
  		break;
  	}
  
  	return 0;
  }
  
  void perf_evlist__to_front(struct perf_evlist *evlist,
  			   struct perf_evsel *move_evsel)
  {
  	struct perf_evsel *evsel, *n;
  	LIST_HEAD(move);
  
  	if (move_evsel == perf_evlist__first(evlist))
  		return;
  
  	evlist__for_each_entry_safe(evlist, n, evsel) {
  		if (evsel->leader == move_evsel->leader)
  			list_move_tail(&evsel->node, &move);
  	}
  
  	list_splice(&move, &evlist->entries);
  }
  
  void perf_evlist__set_tracking_event(struct perf_evlist *evlist,
  				     struct perf_evsel *tracking_evsel)
  {
  	struct perf_evsel *evsel;
  
  	if (tracking_evsel->tracking)
  		return;
  
  	evlist__for_each_entry(evlist, evsel) {
  		if (evsel != tracking_evsel)
  			evsel->tracking = false;
  	}
  
  	tracking_evsel->tracking = true;
  }
  
  struct perf_evsel *
  perf_evlist__find_evsel_by_str(struct perf_evlist *evlist,
  			       const char *str)
  {
  	struct perf_evsel *evsel;
  
  	evlist__for_each_entry(evlist, evsel) {
  		if (!evsel->name)
  			continue;
  		if (strcmp(str, evsel->name) == 0)
  			return evsel;
  	}
  
  	return NULL;
  }
  
  void perf_evlist__toggle_bkw_mmap(struct perf_evlist *evlist,
  				  enum bkw_mmap_state state)
  {
  	enum bkw_mmap_state old_state = evlist->bkw_mmap_state;
  	enum action {
  		NONE,
  		PAUSE,
  		RESUME,
  	} action = NONE;
  
  	if (!evlist->overwrite_mmap)
  		return;
  
  	switch (old_state) {
  	case BKW_MMAP_NOTREADY: {
  		if (state != BKW_MMAP_RUNNING)
  			goto state_err;
  		break;
  	}
  	case BKW_MMAP_RUNNING: {
  		if (state != BKW_MMAP_DATA_PENDING)
  			goto state_err;
  		action = PAUSE;
  		break;
  	}
  	case BKW_MMAP_DATA_PENDING: {
  		if (state != BKW_MMAP_EMPTY)
  			goto state_err;
  		break;
  	}
  	case BKW_MMAP_EMPTY: {
  		if (state != BKW_MMAP_RUNNING)
  			goto state_err;
  		action = RESUME;
  		break;
  	}
  	default:
  		WARN_ONCE(1, "Shouldn't get there\n");
  	}
  
  	evlist->bkw_mmap_state = state;
  
  	switch (action) {
  	case PAUSE:
  		perf_evlist__pause(evlist);
  		break;
  	case RESUME:
  		perf_evlist__resume(evlist);
  		break;
  	case NONE:
  	default:
  		break;
  	}
  
  state_err:
  	return;
  }
  
  bool perf_evlist__exclude_kernel(struct perf_evlist *evlist)
  {
  	struct perf_evsel *evsel;
  
  	evlist__for_each_entry(evlist, evsel) {
  		if (!evsel->attr.exclude_kernel)
  			return false;
  	}
  
  	return true;
  }
  
  /*
   * Events in data file are not collect in groups, but we still want
   * the group display. Set the artificial group and set the leader's
   * forced_leader flag to notify the display code.
   */
  void perf_evlist__force_leader(struct perf_evlist *evlist)
  {
  	if (!evlist->nr_groups) {
  		struct perf_evsel *leader = perf_evlist__first(evlist);
  
  		perf_evlist__set_leader(evlist);
  		leader->forced_leader = true;
  	}
  }
  
  struct perf_evsel *perf_evlist__reset_weak_group(struct perf_evlist *evsel_list,
  						 struct perf_evsel *evsel)
  {
  	struct perf_evsel *c2, *leader;
  	bool is_open = true;
  
  	leader = evsel->leader;
  	pr_debug("Weak group for %s/%d failed\n",
  			leader->name, leader->nr_members);
  
  	/*
  	 * for_each_group_member doesn't work here because it doesn't
  	 * include the first entry.
  	 */
  	evlist__for_each_entry(evsel_list, c2) {
  		if (c2 == evsel)
  			is_open = false;
  		if (c2->leader == leader) {
  			if (is_open)
  				perf_evsel__close(c2);
  			c2->leader = c2;
  			c2->nr_members = 0;
  		}
  	}
  	return leader;
  }
  