session.c

Go to the documentation of this file.

#define _FILE_OFFSET_BITS 64

#include <linux/kernel.h>

#include <byteswap.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/mman.h>

#include "evlist.h"
#include "evsel.h"
#include "session.h"
#include "tool.h"
#include "sort.h"
#include "util.h"
#include "cpumap.h"
#include "event-parse.h"
#include "perf_regs.h"
#include "unwind.h"
#include "vdso.h"

static int perf_session__open(struct perf_session *self, bool force)
{
    struct stat input_stat;

    if (!strcmp(self->filename, "-")) {
        self->fd_pipe = true;
        self->fd = STDIN_FILENO;

        if (perf_session__read_header(self, self->fd) < 0)
            pr_err("incompatible file format (rerun with -v to learn more)");

        return 0;
    }

    self->fd = open(self->filename, O_RDONLY);
    if (self->fd < 0) {
        int err = errno;

        pr_err("failed to open %s: %s", self->filename, strerror(err));
        if (err == ENOENT && !strcmp(self->filename, "perf.data"))
            pr_err("  (try 'perf record' first)");
        pr_err("\n");
        return -errno;
    }

    if (fstat(self->fd, &input_stat) < 0)
        goto out_close;

    if (!force && input_stat.st_uid && (input_stat.st_uid != geteuid())) {
        pr_err("file %s not owned by current user or root\n",
               self->filename);
        goto out_close;
    }

    if (!input_stat.st_size) {
        pr_info("zero-sized file (%s), nothing to do!\n",
            self->filename);
        goto out_close;
    }

    if (perf_session__read_header(self, self->fd) < 0) {
        pr_err("incompatible file format (rerun with -v to learn more)");
        goto out_close;
    }

    if (!perf_evlist__valid_sample_type(self->evlist)) {
        pr_err("non matching sample_type");
        goto out_close;
    }

    if (!perf_evlist__valid_sample_id_all(self->evlist)) {
        pr_err("non matching sample_id_all");
        goto out_close;
    }

    self->size = input_stat.st_size;
    return 0;

out_close:
    close(self->fd);
    self->fd = -1;
    return -1;
}

void perf_session__set_id_hdr_size(struct perf_session *session)
{
    u16 id_hdr_size = perf_evlist__id_hdr_size(session->evlist);

    session->host_machine.id_hdr_size = id_hdr_size;
    machines__set_id_hdr_size(&session->machines, id_hdr_size);
}

int perf_session__create_kernel_maps(struct perf_session *self)
{
    int ret = machine__create_kernel_maps(&self->host_machine);

    if (ret >= 0)
        ret = machines__create_guest_kernel_maps(&self->machines);
    return ret;
}

static void perf_session__destroy_kernel_maps(struct perf_session *self)
{
    machine__destroy_kernel_maps(&self->host_machine);
    machines__destroy_guest_kernel_maps(&self->machines);
}

struct perf_session *perf_session__new(const char *filename, int mode,
                       bool force, bool repipe,
                       struct perf_tool *tool)
{
    struct perf_session *self;
    struct stat st;
    size_t len;

    if (!filename || !strlen(filename)) {
        if (!fstat(STDIN_FILENO, &st) && S_ISFIFO(st.st_mode))
            filename = "-";
        else
            filename = "perf.data";
    }

    len = strlen(filename);
    self = zalloc(sizeof(*self) + len);

    if (self == NULL)
        goto out;

    memcpy(self->filename, filename, len);
    /*
     * On 64bit we can mmap the data file in one go. No need for tiny mmap
     * slices. On 32bit we use 32MB.
     */
#if BITS_PER_LONG == 64
    self->mmap_window = ULLONG_MAX;
#else
    self->mmap_window = 32 * 1024 * 1024ULL;
#endif
    self->machines = RB_ROOT;
    self->repipe = repipe;
    INIT_LIST_HEAD(&self->ordered_samples.samples);
    INIT_LIST_HEAD(&self->ordered_samples.sample_cache);
    INIT_LIST_HEAD(&self->ordered_samples.to_free);
    machine__init(&self->host_machine, "", HOST_KERNEL_ID);
    hists__init(&self->hists);

    if (mode == O_RDONLY) {
        if (perf_session__open(self, force) < 0)
            goto out_delete;
        perf_session__set_id_hdr_size(self);
    } else if (mode == O_WRONLY) {
        /*
         * In O_RDONLY mode this will be performed when reading the
         * kernel MMAP event, in perf_event__process_mmap().
         */
        if (perf_session__create_kernel_maps(self) < 0)
            goto out_delete;
    }

    if (tool && tool->ordering_requires_timestamps &&
        tool->ordered_samples && !perf_evlist__sample_id_all(self->evlist)) {
        dump_printf("WARNING: No sample_id_all support, falling back to unordered processing\n");
        tool->ordered_samples = false;
    }

out:
    return self;
out_delete:
    perf_session__delete(self);
    return NULL;
}

static void machine__delete_dead_threads(struct machine *machine)
{
    struct thread *n, *t;

    list_for_each_entry_safe(t, n, &machine->dead_threads, node) {
        list_del(&t->node);
        thread__delete(t);
    }
}

static void perf_session__delete_dead_threads(struct perf_session *session)
{
    machine__delete_dead_threads(&session->host_machine);
}

static void machine__delete_threads(struct machine *self)
{
    struct rb_node *nd = rb_first(&self->threads);

    while (nd) {
        struct thread *t = rb_entry(nd, struct thread, rb_node);

        rb_erase(&t->rb_node, &self->threads);
        nd = rb_next(nd);
        thread__delete(t);
    }
}

static void perf_session__delete_threads(struct perf_session *session)
{
    machine__delete_threads(&session->host_machine);
}

void perf_session__delete(struct perf_session *self)
{
    perf_session__destroy_kernel_maps(self);
    perf_session__delete_dead_threads(self);
    perf_session__delete_threads(self);
    machine__exit(&self->host_machine);
    close(self->fd);
    free(self);
    vdso__exit();
}

void machine__remove_thread(struct machine *self, struct thread *th)
{
    self->last_match = NULL;
    rb_erase(&th->rb_node, &self->threads);
    /*
     * We may have references to this thread, for instance in some hist_entry
     * instances, so just move them to a separate list.
     */
    list_add_tail(&th->node, &self->dead_threads);
}

static bool symbol__match_parent_regex(struct symbol *sym)
{
    if (sym->name && !regexec(&parent_regex, sym->name, 0, NULL, 0))
        return 1;

    return 0;
}

static const u8 cpumodes[] = {
    PERF_RECORD_MISC_USER,
    PERF_RECORD_MISC_KERNEL,
    PERF_RECORD_MISC_GUEST_USER,
    PERF_RECORD_MISC_GUEST_KERNEL
};
#define NCPUMODES (sizeof(cpumodes)/sizeof(u8))

static void ip__resolve_ams(struct machine *self, struct thread *thread,
                struct addr_map_symbol *ams,
                u64 ip)
{
    struct addr_location al;
    size_t i;
    u8 m;

    memset(&al, 0, sizeof(al));

    for (i = 0; i < NCPUMODES; i++) {
        m = cpumodes[i];
        /*
         * We cannot use the header.misc hint to determine whether a
         * branch stack address is user, kernel, guest, hypervisor.
         * Branches may straddle the kernel/user/hypervisor boundaries.
         * Thus, we have to try consecutively until we find a match
         * or else, the symbol is unknown
         */
        thread__find_addr_location(thread, self, m, MAP__FUNCTION,
                ip, &al, NULL);
        if (al.sym)
            goto found;
    }
found:
    ams->addr = ip;
    ams->al_addr = al.addr;
    ams->sym = al.sym;
    ams->map = al.map;
}

struct branch_info *machine__resolve_bstack(struct machine *self,
                        struct thread *thr,
                        struct branch_stack *bs)
{
    struct branch_info *bi;
    unsigned int i;

    bi = calloc(bs->nr, sizeof(struct branch_info));
    if (!bi)
        return NULL;

    for (i = 0; i < bs->nr; i++) {
        ip__resolve_ams(self, thr, &bi[i].to, bs->entries[i].to);
        ip__resolve_ams(self, thr, &bi[i].from, bs->entries[i].from);
        bi[i].flags = bs->entries[i].flags;
    }
    return bi;
}

static int machine__resolve_callchain_sample(struct machine *machine,
                         struct thread *thread,
                         struct ip_callchain *chain,
                         struct symbol **parent)

{
    u8 cpumode = PERF_RECORD_MISC_USER;
    unsigned int i;
    int err;

    callchain_cursor_reset(&callchain_cursor);

    if (chain->nr > PERF_MAX_STACK_DEPTH) {
        pr_warning("corrupted callchain. skipping...\n");
        return 0;
    }

    for (i = 0; i < chain->nr; i++) {
        u64 ip;
        struct addr_location al;

        if (callchain_param.order == ORDER_CALLEE)
            ip = chain->ips[i];
        else
            ip = chain->ips[chain->nr - i - 1];

        if (ip >= PERF_CONTEXT_MAX) {
            switch (ip) {
            case PERF_CONTEXT_HV:
                cpumode = PERF_RECORD_MISC_HYPERVISOR;
                break;
            case PERF_CONTEXT_KERNEL:
                cpumode = PERF_RECORD_MISC_KERNEL;
                break;
            case PERF_CONTEXT_USER:
                cpumode = PERF_RECORD_MISC_USER;
                break;
            default:
                pr_debug("invalid callchain context: "
                     "%"PRId64"\n", (s64) ip);
                /*
                 * It seems the callchain is corrupted.
                 * Discard all.
                 */
                callchain_cursor_reset(&callchain_cursor);
                return 0;
            }
            continue;
        }

        al.filtered = false;
        thread__find_addr_location(thread, machine, cpumode,
                       MAP__FUNCTION, ip, &al, NULL);
        if (al.sym != NULL) {
            if (sort__has_parent && !*parent &&
                symbol__match_parent_regex(al.sym))
                *parent = al.sym;
            if (!symbol_conf.use_callchain)
                break;
        }

        err = callchain_cursor_append(&callchain_cursor,
                          ip, al.map, al.sym);
        if (err)
            return err;
    }

    return 0;
}

static int unwind_entry(struct unwind_entry *entry, void *arg)
{
    struct callchain_cursor *cursor = arg;
    return callchain_cursor_append(cursor, entry->ip,
                       entry->map, entry->sym);
}

int machine__resolve_callchain(struct machine *machine,
                   struct perf_evsel *evsel,
                   struct thread *thread,
                   struct perf_sample *sample,
                   struct symbol **parent)

{
    int ret;

    callchain_cursor_reset(&callchain_cursor);

    ret = machine__resolve_callchain_sample(machine, thread,
                        sample->callchain, parent);
    if (ret)
        return ret;

    /* Can we do dwarf post unwind? */
    if (!((evsel->attr.sample_type & PERF_SAMPLE_REGS_USER) &&
          (evsel->attr.sample_type & PERF_SAMPLE_STACK_USER)))
        return 0;

    /* Bail out if nothing was captured. */
    if ((!sample->user_regs.regs) ||
        (!sample->user_stack.size))
        return 0;

    return unwind__get_entries(unwind_entry, &callchain_cursor, machine,
                   thread, evsel->attr.sample_regs_user,
                   sample);

}

static int process_event_synth_tracing_data_stub(union perf_event *event
                         __maybe_unused,
                         struct perf_session *session
                        __maybe_unused)
{
    dump_printf(": unhandled!\n");
    return 0;
}

static int process_event_synth_attr_stub(union perf_event *event __maybe_unused,
                     struct perf_evlist **pevlist
                     __maybe_unused)
{
    dump_printf(": unhandled!\n");
    return 0;
}

static int process_event_sample_stub(struct perf_tool *tool __maybe_unused,
                     union perf_event *event __maybe_unused,
                     struct perf_sample *sample __maybe_unused,
                     struct perf_evsel *evsel __maybe_unused,
                     struct machine *machine __maybe_unused)
{
    dump_printf(": unhandled!\n");
    return 0;
}

static int process_event_stub(struct perf_tool *tool __maybe_unused,
                  union perf_event *event __maybe_unused,
                  struct perf_sample *sample __maybe_unused,
                  struct machine *machine __maybe_unused)
{
    dump_printf(": unhandled!\n");
    return 0;
}

static int process_finished_round_stub(struct perf_tool *tool __maybe_unused,
                       union perf_event *event __maybe_unused,
                       struct perf_session *perf_session
                       __maybe_unused)
{
    dump_printf(": unhandled!\n");
    return 0;
}

static int process_event_type_stub(struct perf_tool *tool __maybe_unused,
                   union perf_event *event __maybe_unused)
{
    dump_printf(": unhandled!\n");
    return 0;
}

static int process_finished_round(struct perf_tool *tool,
                  union perf_event *event,
                  struct perf_session *session);

static void perf_tool__fill_defaults(struct perf_tool *tool)
{
    if (tool->sample == NULL)
        tool->sample = process_event_sample_stub;
    if (tool->mmap == NULL)
        tool->mmap = process_event_stub;
    if (tool->comm == NULL)
        tool->comm = process_event_stub;
    if (tool->fork == NULL)
        tool->fork = process_event_stub;
    if (tool->exit == NULL)
        tool->exit = process_event_stub;
    if (tool->lost == NULL)
        tool->lost = perf_event__process_lost;
    if (tool->read == NULL)
        tool->read = process_event_sample_stub;
    if (tool->throttle == NULL)
        tool->throttle = process_event_stub;
    if (tool->unthrottle == NULL)
        tool->unthrottle = process_event_stub;
    if (tool->attr == NULL)
        tool->attr = process_event_synth_attr_stub;
    if (tool->event_type == NULL)
        tool->event_type = process_event_type_stub;
    if (tool->tracing_data == NULL)
        tool->tracing_data = process_event_synth_tracing_data_stub;
    if (tool->build_id == NULL)
        tool->build_id = process_finished_round_stub;
    if (tool->finished_round == NULL) {
        if (tool->ordered_samples)
            tool->finished_round = process_finished_round;
        else
            tool->finished_round = process_finished_round_stub;
    }
}
 
void mem_bswap_32(void *src, int byte_size)
{
    u32 *m = src;
    while (byte_size > 0) {
        *m = bswap_32(*m);
        byte_size -= sizeof(u32);
        ++m;
    }
}

void mem_bswap_64(void *src, int byte_size)
{
    u64 *m = src;

    while (byte_size > 0) {
        *m = bswap_64(*m);
        byte_size -= sizeof(u64);
        ++m;
    }
}

static void swap_sample_id_all(union perf_event *event, void *data)
{
    void *end = (void *) event + event->header.size;
    int size = end - data;

    BUG_ON(size % sizeof(u64));
    mem_bswap_64(data, size);
}

static void perf_event__all64_swap(union perf_event *event,
                   bool sample_id_all __maybe_unused)
{
    struct perf_event_header *hdr = &event->header;
    mem_bswap_64(hdr + 1, event->header.size - sizeof(*hdr));
}

static void perf_event__comm_swap(union perf_event *event, bool sample_id_all)
{
    event->comm.pid = bswap_32(event->comm.pid);
    event->comm.tid = bswap_32(event->comm.tid);

    if (sample_id_all) {
        void *data = &event->comm.comm;

        data += PERF_ALIGN(strlen(data) + 1, sizeof(u64));
        swap_sample_id_all(event, data);
    }
}

static void perf_event__mmap_swap(union perf_event *event,
                  bool sample_id_all)
{
    event->mmap.pid   = bswap_32(event->mmap.pid);
    event->mmap.tid   = bswap_32(event->mmap.tid);
    event->mmap.start = bswap_64(event->mmap.start);
    event->mmap.len   = bswap_64(event->mmap.len);
    event->mmap.pgoff = bswap_64(event->mmap.pgoff);

    if (sample_id_all) {
        void *data = &event->mmap.filename;

        data += PERF_ALIGN(strlen(data) + 1, sizeof(u64));
        swap_sample_id_all(event, data);
    }
}

static void perf_event__task_swap(union perf_event *event, bool sample_id_all)
{
    event->fork.pid  = bswap_32(event->fork.pid);
    event->fork.tid  = bswap_32(event->fork.tid);
    event->fork.ppid = bswap_32(event->fork.ppid);
    event->fork.ptid = bswap_32(event->fork.ptid);
    event->fork.time = bswap_64(event->fork.time);

    if (sample_id_all)
        swap_sample_id_all(event, &event->fork + 1);
}

static void perf_event__read_swap(union perf_event *event, bool sample_id_all)
{
    event->read.pid      = bswap_32(event->read.pid);
    event->read.tid      = bswap_32(event->read.tid);
    event->read.value    = bswap_64(event->read.value);
    event->read.time_enabled = bswap_64(event->read.time_enabled);
    event->read.time_running = bswap_64(event->read.time_running);
    event->read.id       = bswap_64(event->read.id);

    if (sample_id_all)
        swap_sample_id_all(event, &event->read + 1);
}

static u8 revbyte(u8 b)
{
    int rev = (b >> 4) | ((b & 0xf) << 4);
    rev = ((rev & 0xcc) >> 2) | ((rev & 0x33) << 2);
    rev = ((rev & 0xaa) >> 1) | ((rev & 0x55) << 1);
    return (u8) rev;
}

/*
 * XXX this is hack in attempt to carry flags bitfield
 * throught endian village. ABI says:
 *
 * Bit-fields are allocated from right to left (least to most significant)
 * on little-endian implementations and from left to right (most to least
 * significant) on big-endian implementations.
 *
 * The above seems to be byte specific, so we need to reverse each
 * byte of the bitfield. 'Internet' also says this might be implementation
 * specific and we probably need proper fix and carry perf_event_attr
 * bitfield flags in separate data file FEAT_ section. Thought this seems
 * to work for now.
 */
static void swap_bitfield(u8 *p, unsigned len)
{
    unsigned i;

    for (i = 0; i < len; i++) {
        *p = revbyte(*p);
        p++;
    }
}

/* exported for swapping attributes in file header */
void perf_event__attr_swap(struct perf_event_attr *attr)
{
    attr->type      = bswap_32(attr->type);
    attr->size      = bswap_32(attr->size);
    attr->config        = bswap_64(attr->config);
    attr->sample_period = bswap_64(attr->sample_period);
    attr->sample_type   = bswap_64(attr->sample_type);
    attr->read_format   = bswap_64(attr->read_format);
    attr->wakeup_events = bswap_32(attr->wakeup_events);
    attr->bp_type       = bswap_32(attr->bp_type);
    attr->bp_addr       = bswap_64(attr->bp_addr);
    attr->bp_len        = bswap_64(attr->bp_len);

    swap_bitfield((u8 *) (&attr->read_format + 1), sizeof(u64));
}

static void perf_event__hdr_attr_swap(union perf_event *event,
                      bool sample_id_all __maybe_unused)
{
    size_t size;

    perf_event__attr_swap(&event->attr.attr);

    size = event->header.size;
    size -= (void *)&event->attr.id - (void *)event;
    mem_bswap_64(event->attr.id, size);
}

static void perf_event__event_type_swap(union perf_event *event,
                    bool sample_id_all __maybe_unused)
{
    event->event_type.event_type.event_id =
        bswap_64(event->event_type.event_type.event_id);
}

static void perf_event__tracing_data_swap(union perf_event *event,
                      bool sample_id_all __maybe_unused)
{
    event->tracing_data.size = bswap_32(event->tracing_data.size);
}

typedef void (*perf_event__swap_op)(union perf_event *event,
                    bool sample_id_all);

static perf_event__swap_op perf_event__swap_ops[] = {
    [PERF_RECORD_MMAP]        = perf_event__mmap_swap,
    [PERF_RECORD_COMM]        = perf_event__comm_swap,
    [PERF_RECORD_FORK]        = perf_event__task_swap,
    [PERF_RECORD_EXIT]        = perf_event__task_swap,
    [PERF_RECORD_LOST]        = perf_event__all64_swap,
    [PERF_RECORD_READ]        = perf_event__read_swap,
    [PERF_RECORD_SAMPLE]          = perf_event__all64_swap,
    [PERF_RECORD_HEADER_ATTR]     = perf_event__hdr_attr_swap,
    [PERF_RECORD_HEADER_EVENT_TYPE]   = perf_event__event_type_swap,
    [PERF_RECORD_HEADER_TRACING_DATA] = perf_event__tracing_data_swap,
    [PERF_RECORD_HEADER_BUILD_ID]     = NULL,
    [PERF_RECORD_HEADER_MAX]      = NULL,
};

struct sample_queue {
    u64         timestamp;
    u64         file_offset;
    union perf_event    *event;
    struct list_head    list;
};

static void perf_session_free_sample_buffers(struct perf_session *session)
{
    struct ordered_samples *os = &session->ordered_samples;

    while (!list_empty(&os->to_free)) {
        struct sample_queue *sq;

        sq = list_entry(os->to_free.next, struct sample_queue, list);
        list_del(&sq->list);
        free(sq);
    }
}

static int perf_session_deliver_event(struct perf_session *session,
                      union perf_event *event,
                      struct perf_sample *sample,
                      struct perf_tool *tool,
                      u64 file_offset);

static int flush_sample_queue(struct perf_session *s,
                   struct perf_tool *tool)
{
    struct ordered_samples *os = &s->ordered_samples;
    struct list_head *head = &os->samples;
    struct sample_queue *tmp, *iter;
    struct perf_sample sample;
    u64 limit = os->next_flush;
    u64 last_ts = os->last_sample ? os->last_sample->timestamp : 0ULL;
    unsigned idx = 0, progress_next = os->nr_samples / 16;
    int ret;

    if (!tool->ordered_samples || !limit)
        return 0;

    list_for_each_entry_safe(iter, tmp, head, list) {
        if (iter->timestamp > limit)
            break;

        ret = perf_evlist__parse_sample(s->evlist, iter->event, &sample);
        if (ret)
            pr_err("Can't parse sample, err = %d\n", ret);
        else {
            ret = perf_session_deliver_event(s, iter->event, &sample, tool,
                             iter->file_offset);
            if (ret)
                return ret;
        }

        os->last_flush = iter->timestamp;
        list_del(&iter->list);
        list_add(&iter->list, &os->sample_cache);
        if (++idx >= progress_next) {
            progress_next += os->nr_samples / 16;
            ui_progress__update(idx, os->nr_samples,
                        "Processing time ordered events...");
        }
    }

    if (list_empty(head)) {
        os->last_sample = NULL;
    } else if (last_ts <= limit) {
        os->last_sample =
            list_entry(head->prev, struct sample_queue, list);
    }

    os->nr_samples = 0;

    return 0;
}

/*
 * When perf record finishes a pass on every buffers, it records this pseudo
 * event.
 * We record the max timestamp t found in the pass n.
 * Assuming these timestamps are monotonic across cpus, we know that if
 * a buffer still has events with timestamps below t, they will be all
 * available and then read in the pass n + 1.
 * Hence when we start to read the pass n + 2, we can safely flush every
 * events with timestamps below t.
 *
 *    ============ PASS n =================
 *       CPU 0         |   CPU 1
 *                     |
 *    cnt1 timestamps  |   cnt2 timestamps
 *          1          |         2
 *          2          |         3
 *          -          |         4  <--- max recorded
 *
 *    ============ PASS n + 1 ==============
 *       CPU 0         |   CPU 1
 *                     |
 *    cnt1 timestamps  |   cnt2 timestamps
 *          3          |         5
 *          4          |         6
 *          5          |         7 <---- max recorded
 *
 *      Flush every events below timestamp 4
 *
 *    ============ PASS n + 2 ==============
 *       CPU 0         |   CPU 1
 *                     |
 *    cnt1 timestamps  |   cnt2 timestamps
 *          6          |         8
 *          7          |         9
 *          -          |         10
 *
 *      Flush every events below timestamp 7
 *      etc...
 */
static int process_finished_round(struct perf_tool *tool,
                  union perf_event *event __maybe_unused,
                  struct perf_session *session)
{
    int ret = flush_sample_queue(session, tool);
    if (!ret)
        session->ordered_samples.next_flush = session->ordered_samples.max_timestamp;

    return ret;
}

/* The queue is ordered by time */
static void __queue_event(struct sample_queue *new, struct perf_session *s)
{
    struct ordered_samples *os = &s->ordered_samples;
    struct sample_queue *sample = os->last_sample;
    u64 timestamp = new->timestamp;
    struct list_head *p;

    ++os->nr_samples;
    os->last_sample = new;

    if (!sample) {
        list_add(&new->list, &os->samples);
        os->max_timestamp = timestamp;
        return;
    }

    /*
     * last_sample might point to some random place in the list as it's
     * the last queued event. We expect that the new event is close to
     * this.
     */
    if (sample->timestamp <= timestamp) {
        while (sample->timestamp <= timestamp) {
            p = sample->list.next;
            if (p == &os->samples) {
                list_add_tail(&new->list, &os->samples);
                os->max_timestamp = timestamp;
                return;
            }
            sample = list_entry(p, struct sample_queue, list);
        }
        list_add_tail(&new->list, &sample->list);
    } else {
        while (sample->timestamp > timestamp) {
            p = sample->list.prev;
            if (p == &os->samples) {
                list_add(&new->list, &os->samples);
                return;
            }
            sample = list_entry(p, struct sample_queue, list);
        }
        list_add(&new->list, &sample->list);
    }
}

#define MAX_SAMPLE_BUFFER   (64 * 1024 / sizeof(struct sample_queue))

static int perf_session_queue_event(struct perf_session *s, union perf_event *event,
                    struct perf_sample *sample, u64 file_offset)
{
    struct ordered_samples *os = &s->ordered_samples;
    struct list_head *sc = &os->sample_cache;
    u64 timestamp = sample->time;
    struct sample_queue *new;

    if (!timestamp || timestamp == ~0ULL)
        return -ETIME;

    if (timestamp < s->ordered_samples.last_flush) {
        printf("Warning: Timestamp below last timeslice flush\n");
        return -EINVAL;
    }

    if (!list_empty(sc)) {
        new = list_entry(sc->next, struct sample_queue, list);
        list_del(&new->list);
    } else if (os->sample_buffer) {
        new = os->sample_buffer + os->sample_buffer_idx;
        if (++os->sample_buffer_idx == MAX_SAMPLE_BUFFER)
            os->sample_buffer = NULL;
    } else {
        os->sample_buffer = malloc(MAX_SAMPLE_BUFFER * sizeof(*new));
        if (!os->sample_buffer)
            return -ENOMEM;
        list_add(&os->sample_buffer->list, &os->to_free);
        os->sample_buffer_idx = 2;
        new = os->sample_buffer + 1;
    }

    new->timestamp = timestamp;
    new->file_offset = file_offset;
    new->event = event;

    __queue_event(new, s);

    return 0;
}

static void callchain__printf(struct perf_sample *sample)
{
    unsigned int i;

    printf("... chain: nr:%" PRIu64 "\n", sample->callchain->nr);

    for (i = 0; i < sample->callchain->nr; i++)
        printf("..... %2d: %016" PRIx64 "\n",
               i, sample->callchain->ips[i]);
}

static void branch_stack__printf(struct perf_sample *sample)
{
    uint64_t i;

    printf("... branch stack: nr:%" PRIu64 "\n", sample->branch_stack->nr);

    for (i = 0; i < sample->branch_stack->nr; i++)
        printf("..... %2"PRIu64": %016" PRIx64 " -> %016" PRIx64 "\n",
            i, sample->branch_stack->entries[i].from,
            sample->branch_stack->entries[i].to);
}

static void regs_dump__printf(u64 mask, u64 *regs)
{
    unsigned rid, i = 0;

    for_each_set_bit(rid, (unsigned long *) &mask, sizeof(mask) * 8) {
        u64 val = regs[i++];

        printf(".... %-5s 0x%" PRIx64 "\n",
               perf_reg_name(rid), val);
    }
}

static void regs_user__printf(struct perf_sample *sample, u64 mask)
{
    struct regs_dump *user_regs = &sample->user_regs;

    if (user_regs->regs) {
        printf("... user regs: mask 0x%" PRIx64 "\n", mask);
        regs_dump__printf(mask, user_regs->regs);
    }
}

static void stack_user__printf(struct stack_dump *dump)
{
    printf("... ustack: size %" PRIu64 ", offset 0x%x\n",
           dump->size, dump->offset);
}

static void perf_session__print_tstamp(struct perf_session *session,
                       union perf_event *event,
                       struct perf_sample *sample)
{
    u64 sample_type = perf_evlist__sample_type(session->evlist);

    if (event->header.type != PERF_RECORD_SAMPLE &&
        !perf_evlist__sample_id_all(session->evlist)) {
        fputs("-1 -1 ", stdout);
        return;
    }

    if ((sample_type & PERF_SAMPLE_CPU))
        printf("%u ", sample->cpu);

    if (sample_type & PERF_SAMPLE_TIME)
        printf("%" PRIu64 " ", sample->time);
}

static void dump_event(struct perf_session *session, union perf_event *event,
               u64 file_offset, struct perf_sample *sample)
{
    if (!dump_trace)
        return;

    printf("\n%#" PRIx64 " [%#x]: event: %d\n",
           file_offset, event->header.size, event->header.type);

    trace_event(event);

    if (sample)
        perf_session__print_tstamp(session, event, sample);

    printf("%#" PRIx64 " [%#x]: PERF_RECORD_%s", file_offset,
           event->header.size, perf_event__name(event->header.type));
}

static void dump_sample(struct perf_evsel *evsel, union perf_event *event,
            struct perf_sample *sample)
{
    u64 sample_type;

    if (!dump_trace)
        return;

    printf("(IP, %d): %d/%d: %#" PRIx64 " period: %" PRIu64 " addr: %#" PRIx64 "\n",
           event->header.misc, sample->pid, sample->tid, sample->ip,
           sample->period, sample->addr);

    sample_type = evsel->attr.sample_type;

    if (sample_type & PERF_SAMPLE_CALLCHAIN)
        callchain__printf(sample);

    if (sample_type & PERF_SAMPLE_BRANCH_STACK)
        branch_stack__printf(sample);

    if (sample_type & PERF_SAMPLE_REGS_USER)
        regs_user__printf(sample, evsel->attr.sample_regs_user);

    if (sample_type & PERF_SAMPLE_STACK_USER)
        stack_user__printf(&sample->user_stack);
}

static struct machine *
    perf_session__find_machine_for_cpumode(struct perf_session *session,
                           union perf_event *event)
{
    const u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;

    if (perf_guest &&
        ((cpumode == PERF_RECORD_MISC_GUEST_KERNEL) ||
         (cpumode == PERF_RECORD_MISC_GUEST_USER))) {
        u32 pid;

        if (event->header.type == PERF_RECORD_MMAP)
            pid = event->mmap.pid;
        else
            pid = event->ip.pid;

        return perf_session__findnew_machine(session, pid);
    }

    return perf_session__find_host_machine(session);
}

static int perf_session_deliver_event(struct perf_session *session,
                      union perf_event *event,
                      struct perf_sample *sample,
                      struct perf_tool *tool,
                      u64 file_offset)
{
    struct perf_evsel *evsel;
    struct machine *machine;

    dump_event(session, event, file_offset, sample);

    evsel = perf_evlist__id2evsel(session->evlist, sample->id);
    if (evsel != NULL && event->header.type != PERF_RECORD_SAMPLE) {
        /*
         * XXX We're leaving PERF_RECORD_SAMPLE unnacounted here
         * because the tools right now may apply filters, discarding
         * some of the samples. For consistency, in the future we
         * should have something like nr_filtered_samples and remove
         * the sample->period from total_sample_period, etc, KISS for
         * now tho.
         *
         * Also testing against NULL allows us to handle files without
         * attr.sample_id_all and/or without PERF_SAMPLE_ID. In the
         * future probably it'll be a good idea to restrict event
         * processing via perf_session to files with both set.
         */
        hists__inc_nr_events(&evsel->hists, event->header.type);
    }

    machine = perf_session__find_machine_for_cpumode(session, event);

    switch (event->header.type) {
    case PERF_RECORD_SAMPLE:
        dump_sample(evsel, event, sample);
        if (evsel == NULL) {
            ++session->hists.stats.nr_unknown_id;
            return 0;
        }
        if (machine == NULL) {
            ++session->hists.stats.nr_unprocessable_samples;
            return 0;
        }
        return tool->sample(tool, event, sample, evsel, machine);
    case PERF_RECORD_MMAP:
        return tool->mmap(tool, event, sample, machine);
    case PERF_RECORD_COMM:
        return tool->comm(tool, event, sample, machine);
    case PERF_RECORD_FORK:
        return tool->fork(tool, event, sample, machine);
    case PERF_RECORD_EXIT:
        return tool->exit(tool, event, sample, machine);
    case PERF_RECORD_LOST:
        if (tool->lost == perf_event__process_lost)
            session->hists.stats.total_lost += event->lost.lost;
        return tool->lost(tool, event, sample, machine);
    case PERF_RECORD_READ:
        return tool->read(tool, event, sample, evsel, machine);
    case PERF_RECORD_THROTTLE:
        return tool->throttle(tool, event, sample, machine);
    case PERF_RECORD_UNTHROTTLE:
        return tool->unthrottle(tool, event, sample, machine);
    default:
        ++session->hists.stats.nr_unknown_events;
        return -1;
    }
}

static int perf_session__preprocess_sample(struct perf_session *session,
                       union perf_event *event, struct perf_sample *sample)
{
    if (event->header.type != PERF_RECORD_SAMPLE ||
        !(perf_evlist__sample_type(session->evlist) & PERF_SAMPLE_CALLCHAIN))
        return 0;

    if (!ip_callchain__valid(sample->callchain, event)) {
        pr_debug("call-chain problem with event, skipping it.\n");
        ++session->hists.stats.nr_invalid_chains;
        session->hists.stats.total_invalid_chains += sample->period;
        return -EINVAL;
    }
    return 0;
}

static int perf_session__process_user_event(struct perf_session *session, union perf_event *event,
                        struct perf_tool *tool, u64 file_offset)
{
    int err;

    dump_event(session, event, file_offset, NULL);

    /* These events are processed right away */
    switch (event->header.type) {
    case PERF_RECORD_HEADER_ATTR:
        err = tool->attr(event, &session->evlist);
        if (err == 0)
            perf_session__set_id_hdr_size(session);
        return err;
    case PERF_RECORD_HEADER_EVENT_TYPE:
        return tool->event_type(tool, event);
    case PERF_RECORD_HEADER_TRACING_DATA:
        /* setup for reading amidst mmap */
        lseek(session->fd, file_offset, SEEK_SET);
        return tool->tracing_data(event, session);
    case PERF_RECORD_HEADER_BUILD_ID:
        return tool->build_id(tool, event, session);
    case PERF_RECORD_FINISHED_ROUND:
        return tool->finished_round(tool, event, session);
    default:
        return -EINVAL;
    }
}

static void event_swap(union perf_event *event, bool sample_id_all)
{
    perf_event__swap_op swap;

    swap = perf_event__swap_ops[event->header.type];
    if (swap)
        swap(event, sample_id_all);
}

static int perf_session__process_event(struct perf_session *session,
                       union perf_event *event,
                       struct perf_tool *tool,
                       u64 file_offset)
{
    struct perf_sample sample;
    int ret;

    if (session->header.needs_swap)
        event_swap(event, perf_evlist__sample_id_all(session->evlist));

    if (event->header.type >= PERF_RECORD_HEADER_MAX)
        return -EINVAL;

    hists__inc_nr_events(&session->hists, event->header.type);

    if (event->header.type >= PERF_RECORD_USER_TYPE_START)
        return perf_session__process_user_event(session, event, tool, file_offset);

    /*
     * For all kernel events we get the sample data
     */
    ret = perf_evlist__parse_sample(session->evlist, event, &sample);
    if (ret)
        return ret;

    /* Preprocess sample records - precheck callchains */
    if (perf_session__preprocess_sample(session, event, &sample))
        return 0;

    if (tool->ordered_samples) {
        ret = perf_session_queue_event(session, event, &sample,
                           file_offset);
        if (ret != -ETIME)
            return ret;
    }

    return perf_session_deliver_event(session, event, &sample, tool,
                      file_offset);
}

void perf_event_header__bswap(struct perf_event_header *self)
{
    self->type = bswap_32(self->type);
    self->misc = bswap_16(self->misc);
    self->size = bswap_16(self->size);
}

struct thread *perf_session__findnew(struct perf_session *session, pid_t pid)
{
    return machine__findnew_thread(&session->host_machine, pid);
}

static struct thread *perf_session__register_idle_thread(struct perf_session *self)
{
    struct thread *thread = perf_session__findnew(self, 0);

    if (thread == NULL || thread__set_comm(thread, "swapper")) {
        pr_err("problem inserting idle task.\n");
        thread = NULL;
    }

    return thread;
}

static void perf_session__warn_about_errors(const struct perf_session *session,
                        const struct perf_tool *tool)
{
    if (tool->lost == perf_event__process_lost &&
        session->hists.stats.nr_events[PERF_RECORD_LOST] != 0) {
        ui__warning("Processed %d events and lost %d chunks!\n\n"
                "Check IO/CPU overload!\n\n",
                session->hists.stats.nr_events[0],
                session->hists.stats.nr_events[PERF_RECORD_LOST]);
    }

    if (session->hists.stats.nr_unknown_events != 0) {
        ui__warning("Found %u unknown events!\n\n"
                "Is this an older tool processing a perf.data "
                "file generated by a more recent tool?\n\n"
                "If that is not the case, consider "
                "reporting to [email protected].\n\n",
                session->hists.stats.nr_unknown_events);
    }

    if (session->hists.stats.nr_unknown_id != 0) {
        ui__warning("%u samples with id not present in the header\n",
                session->hists.stats.nr_unknown_id);
    }

    if (session->hists.stats.nr_invalid_chains != 0) {
        ui__warning("Found invalid callchains!\n\n"
                "%u out of %u events were discarded for this reason.\n\n"
                "Consider reporting to [email protected].\n\n",
                session->hists.stats.nr_invalid_chains,
                session->hists.stats.nr_events[PERF_RECORD_SAMPLE]);
    }

    if (session->hists.stats.nr_unprocessable_samples != 0) {
        ui__warning("%u unprocessable samples recorded.\n"
                "Do you have a KVM guest running and not using 'perf kvm'?\n",
                session->hists.stats.nr_unprocessable_samples);
    }
}

#define session_done()  (*(volatile int *)(&session_done))
volatile int session_done;

static int __perf_session__process_pipe_events(struct perf_session *self,
                           struct perf_tool *tool)
{
    union perf_event *event;
    uint32_t size, cur_size = 0;
    void *buf = NULL;
    int skip = 0;
    u64 head;
    int err;
    void *p;

    perf_tool__fill_defaults(tool);

    head = 0;
    cur_size = sizeof(union perf_event);

    buf = malloc(cur_size);
    if (!buf)
        return -errno;
more:
    event = buf;
    err = readn(self->fd, event, sizeof(struct perf_event_header));
    if (err <= 0) {
        if (err == 0)
            goto done;

        pr_err("failed to read event header\n");
        goto out_err;
    }

    if (self->header.needs_swap)
        perf_event_header__bswap(&event->header);

    size = event->header.size;
    if (size == 0)
        size = 8;

    if (size > cur_size) {
        void *new = realloc(buf, size);
        if (!new) {
            pr_err("failed to allocate memory to read event\n");
            goto out_err;
        }
        buf = new;
        cur_size = size;
        event = buf;
    }
    p = event;
    p += sizeof(struct perf_event_header);

    if (size - sizeof(struct perf_event_header)) {
        err = readn(self->fd, p, size - sizeof(struct perf_event_header));
        if (err <= 0) {
            if (err == 0) {
                pr_err("unexpected end of event stream\n");
                goto done;
            }

            pr_err("failed to read event data\n");
            goto out_err;
        }
    }

    if ((skip = perf_session__process_event(self, event, tool, head)) < 0) {
        pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
               head, event->header.size, event->header.type);
        err = -EINVAL;
        goto out_err;
    }

    head += size;

    if (skip > 0)
        head += skip;

    if (!session_done())
        goto more;
done:
    err = 0;
out_err:
    free(buf);
    perf_session__warn_about_errors(self, tool);
    perf_session_free_sample_buffers(self);
    return err;
}

static union perf_event *
fetch_mmaped_event(struct perf_session *session,
           u64 head, size_t mmap_size, char *buf)
{
    union perf_event *event;

    /*
     * Ensure we have enough space remaining to read
     * the size of the event in the headers.
     */
    if (head + sizeof(event->header) > mmap_size)
        return NULL;

    event = (union perf_event *)(buf + head);

    if (session->header.needs_swap)
        perf_event_header__bswap(&event->header);

    if (head + event->header.size > mmap_size)
        return NULL;

    return event;
}

int __perf_session__process_events(struct perf_session *session,
                   u64 data_offset, u64 data_size,
                   u64 file_size, struct perf_tool *tool)
{
    u64 head, page_offset, file_offset, file_pos, progress_next;
    int err, mmap_prot, mmap_flags, map_idx = 0;
    size_t  page_size, mmap_size;
    char *buf, *mmaps[8];
    union perf_event *event;
    uint32_t size;

    perf_tool__fill_defaults(tool);

    page_size = sysconf(_SC_PAGESIZE);

    page_offset = page_size * (data_offset / page_size);
    file_offset = page_offset;
    head = data_offset - page_offset;

    if (data_offset + data_size < file_size)
        file_size = data_offset + data_size;

    progress_next = file_size / 16;

    mmap_size = session->mmap_window;
    if (mmap_size > file_size)
        mmap_size = file_size;

    memset(mmaps, 0, sizeof(mmaps));

    mmap_prot  = PROT_READ;
    mmap_flags = MAP_SHARED;

    if (session->header.needs_swap) {
        mmap_prot  |= PROT_WRITE;
        mmap_flags = MAP_PRIVATE;
    }
remap:
    buf = mmap(NULL, mmap_size, mmap_prot, mmap_flags, session->fd,
           file_offset);
    if (buf == MAP_FAILED) {
        pr_err("failed to mmap file\n");
        err = -errno;
        goto out_err;
    }
    mmaps[map_idx] = buf;
    map_idx = (map_idx + 1) & (ARRAY_SIZE(mmaps) - 1);
    file_pos = file_offset + head;

more:
    event = fetch_mmaped_event(session, head, mmap_size, buf);
    if (!event) {
        if (mmaps[map_idx]) {
            munmap(mmaps[map_idx], mmap_size);
            mmaps[map_idx] = NULL;
        }

        page_offset = page_size * (head / page_size);
        file_offset += page_offset;
        head -= page_offset;
        goto remap;
    }

    size = event->header.size;

    if (size == 0 ||
        perf_session__process_event(session, event, tool, file_pos) < 0) {
        pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
               file_offset + head, event->header.size,
               event->header.type);
        err = -EINVAL;
        goto out_err;
    }

    head += size;
    file_pos += size;

    if (file_pos >= progress_next) {
        progress_next += file_size / 16;
        ui_progress__update(file_pos, file_size,
                    "Processing events...");
    }

    if (file_pos < file_size)
        goto more;

    err = 0;
    /* do the final flush for ordered samples */
    session->ordered_samples.next_flush = ULLONG_MAX;
    err = flush_sample_queue(session, tool);
out_err:
    perf_session__warn_about_errors(session, tool);
    perf_session_free_sample_buffers(session);
    return err;
}

int perf_session__process_events(struct perf_session *self,
                 struct perf_tool *tool)
{
    int err;

    if (perf_session__register_idle_thread(self) == NULL)
        return -ENOMEM;

    if (!self->fd_pipe)
        err = __perf_session__process_events(self,
                             self->header.data_offset,
                             self->header.data_size,
                             self->size, tool);
    else
        err = __perf_session__process_pipe_events(self, tool);

    return err;
}

bool perf_session__has_traces(struct perf_session *session, const char *msg)
{
    if (!(perf_evlist__sample_type(session->evlist) & PERF_SAMPLE_RAW)) {
        pr_err("No trace sample to read. Did you call 'perf %s'?\n", msg);
        return false;
    }

    return true;
}

int maps__set_kallsyms_ref_reloc_sym(struct map **maps,
                     const char *symbol_name, u64 addr)
{
    char *bracket;
    enum map_type i;
    struct ref_reloc_sym *ref;

    ref = zalloc(sizeof(struct ref_reloc_sym));
    if (ref == NULL)
        return -ENOMEM;

    ref->name = strdup(symbol_name);
    if (ref->name == NULL) {
        free(ref);
        return -ENOMEM;
    }

    bracket = strchr(ref->name, ']');
    if (bracket)
        *bracket = '\0';

    ref->addr = addr;

    for (i = 0; i < MAP__NR_TYPES; ++i) {
        struct kmap *kmap = map__kmap(maps[i]);
        kmap->ref_reloc_sym = ref;
    }

    return 0;
}

size_t perf_session__fprintf_dsos(struct perf_session *self, FILE *fp)
{
    return __dsos__fprintf(&self->host_machine.kernel_dsos, fp) +
           __dsos__fprintf(&self->host_machine.user_dsos, fp) +
           machines__fprintf_dsos(&self->machines, fp);
}

size_t perf_session__fprintf_dsos_buildid(struct perf_session *self, FILE *fp,
                      bool with_hits)
{
    size_t ret = machine__fprintf_dsos_buildid(&self->host_machine, fp, with_hits);
    return ret + machines__fprintf_dsos_buildid(&self->machines, fp, with_hits);
}

size_t perf_session__fprintf_nr_events(struct perf_session *session, FILE *fp)
{
    struct perf_evsel *pos;
    size_t ret = fprintf(fp, "Aggregated stats:\n");

    ret += hists__fprintf_nr_events(&session->hists, fp);

    list_for_each_entry(pos, &session->evlist->entries, node) {
        ret += fprintf(fp, "%s stats:\n", perf_evsel__name(pos));
        ret += hists__fprintf_nr_events(&pos->hists, fp);
    }

    return ret;
}

size_t perf_session__fprintf(struct perf_session *session, FILE *fp)
{
    /*
     * FIXME: Here we have to actually print all the machines in this
     * session, not just the host...
     */
    return machine__fprintf(&session->host_machine, fp);
}

void perf_session__remove_thread(struct perf_session *session,
                 struct thread *th)
{
    /*
     * FIXME: This one makes no sense, we need to remove the thread from
     * the machine it belongs to, perf_session can have many machines, so
     * doing it always on ->host_machine is wrong.  Fix when auditing all
     * the 'perf kvm' code.
     */
    machine__remove_thread(&session->host_machine, th);
}

struct perf_evsel *perf_session__find_first_evtype(struct perf_session *session,
                          unsigned int type)
{
    struct perf_evsel *pos;

    list_for_each_entry(pos, &session->evlist->entries, node) {
        if (pos->attr.type == type)
            return pos;
    }
    return NULL;
}

void perf_evsel__print_ip(struct perf_evsel *evsel, union perf_event *event,
              struct perf_sample *sample, struct machine *machine,
              int print_sym, int print_dso, int print_symoffset)
{
    struct addr_location al;
    struct callchain_cursor_node *node;

    if (perf_event__preprocess_sample(event, machine, &al, sample,
                      NULL) < 0) {
        error("problem processing %d event, skipping it.\n",
            event->header.type);
        return;
    }

    if (symbol_conf.use_callchain && sample->callchain) {


        if (machine__resolve_callchain(machine, evsel, al.thread,
                           sample, NULL) != 0) {
            if (verbose)
                error("Failed to resolve callchain. Skipping\n");
            return;
        }
        callchain_cursor_commit(&callchain_cursor);

        while (1) {
            node = callchain_cursor_current(&callchain_cursor);
            if (!node)
                break;

            printf("\t%16" PRIx64, node->ip);
            if (print_sym) {
                printf(" ");
                symbol__fprintf_symname(node->sym, stdout);
            }
            if (print_dso) {
                printf(" (");
                map__fprintf_dsoname(node->map, stdout);
                printf(")");
            }
            printf("\n");

            callchain_cursor_advance(&callchain_cursor);
        }

    } else {
        printf("%16" PRIx64, sample->ip);
        if (print_sym) {
            printf(" ");
            if (print_symoffset)
                symbol__fprintf_symname_offs(al.sym, &al,
                                 stdout);
            else
                symbol__fprintf_symname(al.sym, stdout);
        }

        if (print_dso) {
            printf(" (");
            map__fprintf_dsoname(al.map, stdout);
            printf(")");
        }
    }
}

int perf_session__cpu_bitmap(struct perf_session *session,
                 const char *cpu_list, unsigned long *cpu_bitmap)
{
    int i;
    struct cpu_map *map;

    for (i = 0; i < PERF_TYPE_MAX; ++i) {
        struct perf_evsel *evsel;

        evsel = perf_session__find_first_evtype(session, i);
        if (!evsel)
            continue;

        if (!(evsel->attr.sample_type & PERF_SAMPLE_CPU)) {
            pr_err("File does not contain CPU events. "
                   "Remove -c option to proceed.\n");
            return -1;
        }
    }

    map = cpu_map__new(cpu_list);
    if (map == NULL) {
        pr_err("Invalid cpu_list\n");
        return -1;
    }

    for (i = 0; i < map->nr; i++) {
        int cpu = map->map[i];

        if (cpu >= MAX_NR_CPUS) {
            pr_err("Requested CPU %d too large. "
                   "Consider raising MAX_NR_CPUS\n", cpu);
            return -1;
        }

        set_bit(cpu, cpu_bitmap);
    }

    return 0;
}

void perf_session__fprintf_info(struct perf_session *session, FILE *fp,
                bool full)
{
    struct stat st;
    int ret;

    if (session == NULL || fp == NULL)
        return;

    ret = fstat(session->fd, &st);
    if (ret == -1)
        return;

    fprintf(fp, "# ========\n");
    fprintf(fp, "# captured on: %s", ctime(&st.st_ctime));
    perf_header__fprintf_info(session, fp, full);
    fprintf(fp, "# ========\n#\n");
}


int __perf_session__set_tracepoints_handlers(struct perf_session *session,
                         const struct perf_evsel_str_handler *assocs,
                         size_t nr_assocs)
{
    struct perf_evlist *evlist = session->evlist;
    struct event_format *format;
    struct perf_evsel *evsel;
    char *tracepoint, *name;
    size_t i;
    int err;

    for (i = 0; i < nr_assocs; i++) {
        err = -ENOMEM;
        tracepoint = strdup(assocs[i].name);
        if (tracepoint == NULL)
            goto out;

        err = -ENOENT;
        name = strchr(tracepoint, ':');
        if (name == NULL)
            goto out_free;

        *name++ = '\0';
        format = pevent_find_event_by_name(session->pevent,
                           tracepoint, name);
        if (format == NULL) {
            /*
             * Adding a handler for an event not in the session,
             * just ignore it.
             */
            goto next;
        }

        evsel = perf_evlist__find_tracepoint_by_id(evlist, format->id);
        if (evsel == NULL)
            goto next;

        err = -EEXIST;
        if (evsel->handler.func != NULL)
            goto out_free;
        evsel->handler.func = assocs[i].handler;
next:
        free(tracepoint);
    }

    err = 0;
out:
    return err;

out_free:
    free(tracepoint);
    goto out;
}