evlist.c

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/*
 * 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;
}

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 (!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)  < 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);
}

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;
    }
}