event.c

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// SPDX-License-Identifier: GPL-2.0
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <uapi/linux/mman.h> /* To get things like MAP_HUGETLB even on older libc headers */
#include <api/fs/fs.h>
#include <linux/perf_event.h>
#include "event.h"
#include "debug.h"
#include "hist.h"
#include "machine.h"
#include "sort.h"
#include "string2.h"
#include "strlist.h"
#include "thread.h"
#include "thread_map.h"
#include "sane_ctype.h"
#include "symbol/kallsyms.h"
#include "asm/bug.h"
#include "stat.h"

static const char *perf_event__names[] = {
    [0]                 = "TOTAL",
    [PERF_RECORD_MMAP]          = "MMAP",
    [PERF_RECORD_MMAP2]         = "MMAP2",
    [PERF_RECORD_LOST]          = "LOST",
    [PERF_RECORD_COMM]          = "COMM",
    [PERF_RECORD_EXIT]          = "EXIT",
    [PERF_RECORD_THROTTLE]          = "THROTTLE",
    [PERF_RECORD_UNTHROTTLE]        = "UNTHROTTLE",
    [PERF_RECORD_FORK]          = "FORK",
    [PERF_RECORD_READ]          = "READ",
    [PERF_RECORD_SAMPLE]            = "SAMPLE",
    [PERF_RECORD_AUX]           = "AUX",
    [PERF_RECORD_ITRACE_START]      = "ITRACE_START",
    [PERF_RECORD_LOST_SAMPLES]      = "LOST_SAMPLES",
    [PERF_RECORD_SWITCH]            = "SWITCH",
    [PERF_RECORD_SWITCH_CPU_WIDE]       = "SWITCH_CPU_WIDE",
    [PERF_RECORD_NAMESPACES]        = "NAMESPACES",
    [PERF_RECORD_HEADER_ATTR]       = "ATTR",
    [PERF_RECORD_HEADER_EVENT_TYPE]     = "EVENT_TYPE",
    [PERF_RECORD_HEADER_TRACING_DATA]   = "TRACING_DATA",
    [PERF_RECORD_HEADER_BUILD_ID]       = "BUILD_ID",
    [PERF_RECORD_FINISHED_ROUND]        = "FINISHED_ROUND",
    [PERF_RECORD_ID_INDEX]          = "ID_INDEX",
    [PERF_RECORD_AUXTRACE_INFO]     = "AUXTRACE_INFO",
    [PERF_RECORD_AUXTRACE]          = "AUXTRACE",
    [PERF_RECORD_AUXTRACE_ERROR]        = "AUXTRACE_ERROR",
    [PERF_RECORD_THREAD_MAP]        = "THREAD_MAP",
    [PERF_RECORD_CPU_MAP]           = "CPU_MAP",
    [PERF_RECORD_STAT_CONFIG]       = "STAT_CONFIG",
    [PERF_RECORD_STAT]          = "STAT",
    [PERF_RECORD_STAT_ROUND]        = "STAT_ROUND",
    [PERF_RECORD_EVENT_UPDATE]      = "EVENT_UPDATE",
    [PERF_RECORD_TIME_CONV]         = "TIME_CONV",
    [PERF_RECORD_HEADER_FEATURE]        = "FEATURE",
};

static const char *perf_ns__names[] = {
    [NET_NS_INDEX]      = "net",
    [UTS_NS_INDEX]      = "uts",
    [IPC_NS_INDEX]      = "ipc",
    [PID_NS_INDEX]      = "pid",
    [USER_NS_INDEX]     = "user",
    [MNT_NS_INDEX]      = "mnt",
    [CGROUP_NS_INDEX]   = "cgroup",
};

const char *perf_event__name(unsigned int id)
{
    if (id >= ARRAY_SIZE(perf_event__names))
        return "INVALID";
    if (!perf_event__names[id])
        return "UNKNOWN";
    return perf_event__names[id];
}

static const char *perf_ns__name(unsigned int id)
{
    if (id >= ARRAY_SIZE(perf_ns__names))
        return "UNKNOWN";
    return perf_ns__names[id];
}

int perf_tool__process_synth_event(struct perf_tool *tool,
                   union perf_event *event,
                   struct machine *machine,
                   perf_event__handler_t process)
{
    struct perf_sample synth_sample = {
    .pid       = -1,
    .tid       = -1,
    .time      = -1,
    .stream_id = -1,
    .cpu       = -1,
    .period    = 1,
    .cpumode   = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK,
    };

    return process(tool, event, &synth_sample, machine);
};

/*
 * Assumes that the first 4095 bytes of /proc/pid/stat contains
 * the comm, tgid and ppid.
 */
static int perf_event__get_comm_ids(pid_t pid, char *comm, size_t len,
                    pid_t *tgid, pid_t *ppid)
{
    char filename[PATH_MAX];
    char bf[4096];
    int fd;
    size_t size = 0;
    ssize_t n;
    char *name, *tgids, *ppids;

    *tgid = -1;
    *ppid = -1;

    snprintf(filename, sizeof(filename), "/proc/%d/status", pid);

    fd = open(filename, O_RDONLY);
    if (fd < 0) {
        pr_debug("couldn't open %s\n", filename);
        return -1;
    }

    n = read(fd, bf, sizeof(bf) - 1);
    close(fd);
    if (n <= 0) {
        pr_warning("Couldn't get COMM, tigd and ppid for pid %d\n",
               pid);
        return -1;
    }
    bf[n] = '\0';

    name = strstr(bf, "Name:");
    tgids = strstr(bf, "Tgid:");
    ppids = strstr(bf, "PPid:");

    if (name) {
        char *nl;

        name += 5;  /* strlen("Name:") */
        name = ltrim(name);

        nl = strchr(name, '\n');
        if (nl)
            *nl = '\0';

        size = strlen(name);
        if (size >= len)
            size = len - 1;
        memcpy(comm, name, size);
        comm[size] = '\0';
    } else {
        pr_debug("Name: string not found for pid %d\n", pid);
    }

    if (tgids) {
        tgids += 5;  /* strlen("Tgid:") */
        *tgid = atoi(tgids);
    } else {
        pr_debug("Tgid: string not found for pid %d\n", pid);
    }

    if (ppids) {
        ppids += 5;  /* strlen("PPid:") */
        *ppid = atoi(ppids);
    } else {
        pr_debug("PPid: string not found for pid %d\n", pid);
    }

    return 0;
}

static int perf_event__prepare_comm(union perf_event *event, pid_t pid,
                    struct machine *machine,
                    pid_t *tgid, pid_t *ppid)
{
    size_t size;

    *ppid = -1;

    memset(&event->comm, 0, sizeof(event->comm));

    if (machine__is_host(machine)) {
        if (perf_event__get_comm_ids(pid, event->comm.comm,
                         sizeof(event->comm.comm),
                         tgid, ppid) != 0) {
            return -1;
        }
    } else {
        *tgid = machine->pid;
    }

    if (*tgid < 0)
        return -1;

    event->comm.pid = *tgid;
    event->comm.header.type = PERF_RECORD_COMM;

    size = strlen(event->comm.comm) + 1;
    size = PERF_ALIGN(size, sizeof(u64));
    memset(event->comm.comm + size, 0, machine->id_hdr_size);
    event->comm.header.size = (sizeof(event->comm) -
                (sizeof(event->comm.comm) - size) +
                machine->id_hdr_size);
    event->comm.tid = pid;

    return 0;
}

pid_t perf_event__synthesize_comm(struct perf_tool *tool,
                     union perf_event *event, pid_t pid,
                     perf_event__handler_t process,
                     struct machine *machine)
{
    pid_t tgid, ppid;

    if (perf_event__prepare_comm(event, pid, machine, &tgid, &ppid) != 0)
        return -1;

    if (perf_tool__process_synth_event(tool, event, machine, process) != 0)
        return -1;

    return tgid;
}

static void perf_event__get_ns_link_info(pid_t pid, const char *ns,
                     struct perf_ns_link_info *ns_link_info)
{
    struct stat64 st;
    char proc_ns[128];

    sprintf(proc_ns, "/proc/%u/ns/%s", pid, ns);
    if (stat64(proc_ns, &st) == 0) {
        ns_link_info->dev = st.st_dev;
        ns_link_info->ino = st.st_ino;
    }
}

int perf_event__synthesize_namespaces(struct perf_tool *tool,
                      union perf_event *event,
                      pid_t pid, pid_t tgid,
                      perf_event__handler_t process,
                      struct machine *machine)
{
    u32 idx;
    struct perf_ns_link_info *ns_link_info;

    if (!tool || !tool->namespace_events)
        return 0;

    memset(&event->namespaces, 0, (sizeof(event->namespaces) +
           (NR_NAMESPACES * sizeof(struct perf_ns_link_info)) +
           machine->id_hdr_size));

    event->namespaces.pid = tgid;
    event->namespaces.tid = pid;

    event->namespaces.nr_namespaces = NR_NAMESPACES;

    ns_link_info = event->namespaces.link_info;

    for (idx = 0; idx < event->namespaces.nr_namespaces; idx++)
        perf_event__get_ns_link_info(pid, perf_ns__name(idx),
                         &ns_link_info[idx]);

    event->namespaces.header.type = PERF_RECORD_NAMESPACES;

    event->namespaces.header.size = (sizeof(event->namespaces) +
            (NR_NAMESPACES * sizeof(struct perf_ns_link_info)) +
            machine->id_hdr_size);

    if (perf_tool__process_synth_event(tool, event, machine, process) != 0)
        return -1;

    return 0;
}

static int perf_event__synthesize_fork(struct perf_tool *tool,
                       union perf_event *event,
                       pid_t pid, pid_t tgid, pid_t ppid,
                       perf_event__handler_t process,
                       struct machine *machine)
{
    memset(&event->fork, 0, sizeof(event->fork) + machine->id_hdr_size);

    /*
     * for main thread set parent to ppid from status file. For other
     * threads set parent pid to main thread. ie., assume main thread
     * spawns all threads in a process
    */
    if (tgid == pid) {
        event->fork.ppid = ppid;
        event->fork.ptid = ppid;
    } else {
        event->fork.ppid = tgid;
        event->fork.ptid = tgid;
    }
    event->fork.pid  = tgid;
    event->fork.tid  = pid;
    event->fork.header.type = PERF_RECORD_FORK;

    event->fork.header.size = (sizeof(event->fork) + machine->id_hdr_size);

    if (perf_tool__process_synth_event(tool, event, machine, process) != 0)
        return -1;

    return 0;
}

int perf_event__synthesize_mmap_events(struct perf_tool *tool,
                       union perf_event *event,
                       pid_t pid, pid_t tgid,
                       perf_event__handler_t process,
                       struct machine *machine,
                       bool mmap_data,
                       unsigned int proc_map_timeout)
{
    char filename[PATH_MAX];
    FILE *fp;
    unsigned long long t;
    bool truncation = false;
    unsigned long long timeout = proc_map_timeout * 1000000ULL;
    int rc = 0;
    const char *hugetlbfs_mnt = hugetlbfs__mountpoint();
    int hugetlbfs_mnt_len = hugetlbfs_mnt ? strlen(hugetlbfs_mnt) : 0;

    if (machine__is_default_guest(machine))
        return 0;

    snprintf(filename, sizeof(filename), "%s/proc/%d/task/%d/maps",
         machine->root_dir, pid, pid);

    fp = fopen(filename, "r");
    if (fp == NULL) {
        /*
         * We raced with a task exiting - just return:
         */
        pr_debug("couldn't open %s\n", filename);
        return -1;
    }

    event->header.type = PERF_RECORD_MMAP2;
    t = rdclock();

    while (1) {
        char bf[BUFSIZ];
        char prot[5];
        char execname[PATH_MAX];
        char anonstr[] = "//anon";
        unsigned int ino;
        size_t size;
        ssize_t n;

        if (fgets(bf, sizeof(bf), fp) == NULL)
            break;

        if ((rdclock() - t) > timeout) {
            pr_warning("Reading %s time out. "
                   "You may want to increase "
                   "the time limit by --proc-map-timeout\n",
                   filename);
            truncation = true;
            goto out;
        }

        /* ensure null termination since stack will be reused. */
        strcpy(execname, "");

        /* 00400000-0040c000 r-xp 00000000 fd:01 41038  /bin/cat */
        n = sscanf(bf, "%"PRIx64"-%"PRIx64" %s %"PRIx64" %x:%x %u %[^\n]\n",
               &event->mmap2.start, &event->mmap2.len, prot,
               &event->mmap2.pgoff, &event->mmap2.maj,
               &event->mmap2.min,
               &ino, execname);

        /*
         * Anon maps don't have the execname.
         */
        if (n < 7)
            continue;

        event->mmap2.ino = (u64)ino;

        /*
         * Just like the kernel, see __perf_event_mmap in kernel/perf_event.c
         */
        if (machine__is_host(machine))
            event->header.misc = PERF_RECORD_MISC_USER;
        else
            event->header.misc = PERF_RECORD_MISC_GUEST_USER;

        /* map protection and flags bits */
        event->mmap2.prot = 0;
        event->mmap2.flags = 0;
        if (prot[0] == 'r')
            event->mmap2.prot |= PROT_READ;
        if (prot[1] == 'w')
            event->mmap2.prot |= PROT_WRITE;
        if (prot[2] == 'x')
            event->mmap2.prot |= PROT_EXEC;

        if (prot[3] == 's')
            event->mmap2.flags |= MAP_SHARED;
        else
            event->mmap2.flags |= MAP_PRIVATE;

        if (prot[2] != 'x') {
            if (!mmap_data || prot[0] != 'r')
                continue;

            event->header.misc |= PERF_RECORD_MISC_MMAP_DATA;
        }

out:
        if (truncation)
            event->header.misc |= PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT;

        if (!strcmp(execname, ""))
            strcpy(execname, anonstr);

        if (hugetlbfs_mnt_len &&
            !strncmp(execname, hugetlbfs_mnt, hugetlbfs_mnt_len)) {
            strcpy(execname, anonstr);
            event->mmap2.flags |= MAP_HUGETLB;
        }

        size = strlen(execname) + 1;
        memcpy(event->mmap2.filename, execname, size);
        size = PERF_ALIGN(size, sizeof(u64));
        event->mmap2.len -= event->mmap.start;
        event->mmap2.header.size = (sizeof(event->mmap2) -
                    (sizeof(event->mmap2.filename) - size));
        memset(event->mmap2.filename + size, 0, machine->id_hdr_size);
        event->mmap2.header.size += machine->id_hdr_size;
        event->mmap2.pid = tgid;
        event->mmap2.tid = pid;

        if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
            rc = -1;
            break;
        }

        if (truncation)
            break;
    }

    fclose(fp);
    return rc;
}

int perf_event__synthesize_modules(struct perf_tool *tool,
                   perf_event__handler_t process,
                   struct machine *machine)
{
    int rc = 0;
    struct map *pos;
    struct maps *maps = machine__kernel_maps(machine);
    union perf_event *event = zalloc((sizeof(event->mmap) +
                      machine->id_hdr_size));
    if (event == NULL) {
        pr_debug("Not enough memory synthesizing mmap event "
             "for kernel modules\n");
        return -1;
    }

    event->header.type = PERF_RECORD_MMAP;

    /*
     * kernel uses 0 for user space maps, see kernel/perf_event.c
     * __perf_event_mmap
     */
    if (machine__is_host(machine))
        event->header.misc = PERF_RECORD_MISC_KERNEL;
    else
        event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;

    for (pos = maps__first(maps); pos; pos = map__next(pos)) {
        size_t size;

        if (!__map__is_kmodule(pos))
            continue;

        size = PERF_ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
        event->mmap.header.type = PERF_RECORD_MMAP;
        event->mmap.header.size = (sizeof(event->mmap) -
                        (sizeof(event->mmap.filename) - size));
        memset(event->mmap.filename + size, 0, machine->id_hdr_size);
        event->mmap.header.size += machine->id_hdr_size;
        event->mmap.start = pos->start;
        event->mmap.len   = pos->end - pos->start;
        event->mmap.pid   = machine->pid;

        memcpy(event->mmap.filename, pos->dso->long_name,
               pos->dso->long_name_len + 1);
        if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
            rc = -1;
            break;
        }
    }

    free(event);
    return rc;
}

static int __event__synthesize_thread(union perf_event *comm_event,
                      union perf_event *mmap_event,
                      union perf_event *fork_event,
                      union perf_event *namespaces_event,
                      pid_t pid, int full,
                      perf_event__handler_t process,
                      struct perf_tool *tool,
                      struct machine *machine,
                      bool mmap_data,
                      unsigned int proc_map_timeout)
{
    char filename[PATH_MAX];
    DIR *tasks;
    struct dirent *dirent;
    pid_t tgid, ppid;
    int rc = 0;

    /* special case: only send one comm event using passed in pid */
    if (!full) {
        tgid = perf_event__synthesize_comm(tool, comm_event, pid,
                           process, machine);

        if (tgid == -1)
            return -1;

        if (perf_event__synthesize_namespaces(tool, namespaces_event, pid,
                              tgid, process, machine) < 0)
            return -1;


        return perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
                              process, machine, mmap_data,
                              proc_map_timeout);
    }

    if (machine__is_default_guest(machine))
        return 0;

    snprintf(filename, sizeof(filename), "%s/proc/%d/task",
         machine->root_dir, pid);

    tasks = opendir(filename);
    if (tasks == NULL) {
        pr_debug("couldn't open %s\n", filename);
        return 0;
    }

    while ((dirent = readdir(tasks)) != NULL) {
        char *end;
        pid_t _pid;

        _pid = strtol(dirent->d_name, &end, 10);
        if (*end)
            continue;

        rc = -1;
        if (perf_event__prepare_comm(comm_event, _pid, machine,
                         &tgid, &ppid) != 0)
            break;

        if (perf_event__synthesize_fork(tool, fork_event, _pid, tgid,
                        ppid, process, machine) < 0)
            break;

        if (perf_event__synthesize_namespaces(tool, namespaces_event, _pid,
                              tgid, process, machine) < 0)
            break;

        /*
         * Send the prepared comm event
         */
        if (perf_tool__process_synth_event(tool, comm_event, machine, process) != 0)
            break;

        rc = 0;
        if (_pid == pid) {
            /* process the parent's maps too */
            rc = perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
                        process, machine, mmap_data, proc_map_timeout);
            if (rc)
                break;
        }
    }

    closedir(tasks);
    return rc;
}

int perf_event__synthesize_thread_map(struct perf_tool *tool,
                      struct thread_map *threads,
                      perf_event__handler_t process,
                      struct machine *machine,
                      bool mmap_data,
                      unsigned int proc_map_timeout)
{
    union perf_event *comm_event, *mmap_event, *fork_event;
    union perf_event *namespaces_event;
    int err = -1, thread, j;

    comm_event = malloc(sizeof(comm_event->comm) + machine->id_hdr_size);
    if (comm_event == NULL)
        goto out;

    mmap_event = malloc(sizeof(mmap_event->mmap2) + machine->id_hdr_size);
    if (mmap_event == NULL)
        goto out_free_comm;

    fork_event = malloc(sizeof(fork_event->fork) + machine->id_hdr_size);
    if (fork_event == NULL)
        goto out_free_mmap;

    namespaces_event = malloc(sizeof(namespaces_event->namespaces) +
                  (NR_NAMESPACES * sizeof(struct perf_ns_link_info)) +
                  machine->id_hdr_size);
    if (namespaces_event == NULL)
        goto out_free_fork;

    err = 0;
    for (thread = 0; thread < threads->nr; ++thread) {
        if (__event__synthesize_thread(comm_event, mmap_event,
                           fork_event, namespaces_event,
                           thread_map__pid(threads, thread), 0,
                           process, tool, machine,
                           mmap_data, proc_map_timeout)) {
            err = -1;
            break;
        }

        /*
         * comm.pid is set to thread group id by
         * perf_event__synthesize_comm
         */
        if ((int) comm_event->comm.pid != thread_map__pid(threads, thread)) {
            bool need_leader = true;

            /* is thread group leader in thread_map? */
            for (j = 0; j < threads->nr; ++j) {
                if ((int) comm_event->comm.pid == thread_map__pid(threads, j)) {
                    need_leader = false;
                    break;
                }
            }

            /* if not, generate events for it */
            if (need_leader &&
                __event__synthesize_thread(comm_event, mmap_event,
                               fork_event, namespaces_event,
                               comm_event->comm.pid, 0,
                               process, tool, machine,
                               mmap_data, proc_map_timeout)) {
                err = -1;
                break;
            }
        }
    }
    free(namespaces_event);
out_free_fork:
    free(fork_event);
out_free_mmap:
    free(mmap_event);
out_free_comm:
    free(comm_event);
out:
    return err;
}

static int __perf_event__synthesize_threads(struct perf_tool *tool,
                        perf_event__handler_t process,
                        struct machine *machine,
                        bool mmap_data,
                        unsigned int proc_map_timeout,
                        struct dirent **dirent,
                        int start,
                        int num)
{
    union perf_event *comm_event, *mmap_event, *fork_event;
    union perf_event *namespaces_event;
    int err = -1;
    char *end;
    pid_t pid;
    int i;

    comm_event = malloc(sizeof(comm_event->comm) + machine->id_hdr_size);
    if (comm_event == NULL)
        goto out;

    mmap_event = malloc(sizeof(mmap_event->mmap2) + machine->id_hdr_size);
    if (mmap_event == NULL)
        goto out_free_comm;

    fork_event = malloc(sizeof(fork_event->fork) + machine->id_hdr_size);
    if (fork_event == NULL)
        goto out_free_mmap;

    namespaces_event = malloc(sizeof(namespaces_event->namespaces) +
                  (NR_NAMESPACES * sizeof(struct perf_ns_link_info)) +
                  machine->id_hdr_size);
    if (namespaces_event == NULL)
        goto out_free_fork;

    for (i = start; i < start + num; i++) {
        if (!isdigit(dirent[i]->d_name[0]))
            continue;

        pid = (pid_t)strtol(dirent[i]->d_name, &end, 10);
        /* only interested in proper numerical dirents */
        if (*end)
            continue;
        /*
         * We may race with exiting thread, so don't stop just because
         * one thread couldn't be synthesized.
         */
        __event__synthesize_thread(comm_event, mmap_event, fork_event,
                       namespaces_event, pid, 1, process,
                       tool, machine, mmap_data,
                       proc_map_timeout);
    }
    err = 0;

    free(namespaces_event);
out_free_fork:
    free(fork_event);
out_free_mmap:
    free(mmap_event);
out_free_comm:
    free(comm_event);
out:
    return err;
}

struct synthesize_threads_arg {
    struct perf_tool *tool;
    perf_event__handler_t process;
    struct machine *machine;
    bool mmap_data;
    unsigned int proc_map_timeout;
    struct dirent **dirent;
    int num;
    int start;
};

static void *synthesize_threads_worker(void *arg)
{
    struct synthesize_threads_arg *args = arg;

    __perf_event__synthesize_threads(args->tool, args->process,
                     args->machine, args->mmap_data,
                     args->proc_map_timeout, args->dirent,
                     args->start, args->num);
    return NULL;
}

int perf_event__synthesize_threads(struct perf_tool *tool,
                   perf_event__handler_t process,
                   struct machine *machine,
                   bool mmap_data,
                   unsigned int proc_map_timeout,
                   unsigned int nr_threads_synthesize)
{
    struct synthesize_threads_arg *args = NULL;
    pthread_t *synthesize_threads = NULL;
    char proc_path[PATH_MAX];
    struct dirent **dirent;
    int num_per_thread;
    int m, n, i, j;
    int thread_nr;
    int base = 0;
    int err = -1;


    if (machine__is_default_guest(machine))
        return 0;

    snprintf(proc_path, sizeof(proc_path), "%s/proc", machine->root_dir);
    n = scandir(proc_path, &dirent, 0, alphasort);
    if (n < 0)
        return err;

    if (nr_threads_synthesize == UINT_MAX)
        thread_nr = sysconf(_SC_NPROCESSORS_ONLN);
    else
        thread_nr = nr_threads_synthesize;

    if (thread_nr <= 1) {
        err = __perf_event__synthesize_threads(tool, process,
                               machine, mmap_data,
                               proc_map_timeout,
                               dirent, base, n);
        goto free_dirent;
    }
    if (thread_nr > n)
        thread_nr = n;

    synthesize_threads = calloc(sizeof(pthread_t), thread_nr);
    if (synthesize_threads == NULL)
        goto free_dirent;

    args = calloc(sizeof(*args), thread_nr);
    if (args == NULL)
        goto free_threads;

    num_per_thread = n / thread_nr;
    m = n % thread_nr;
    for (i = 0; i < thread_nr; i++) {
        args[i].tool = tool;
        args[i].process = process;
        args[i].machine = machine;
        args[i].mmap_data = mmap_data;
        args[i].proc_map_timeout = proc_map_timeout;
        args[i].dirent = dirent;
    }
    for (i = 0; i < m; i++) {
        args[i].num = num_per_thread + 1;
        args[i].start = i * args[i].num;
    }
    if (i != 0)
        base = args[i-1].start + args[i-1].num;
    for (j = i; j < thread_nr; j++) {
        args[j].num = num_per_thread;
        args[j].start = base + (j - i) * args[i].num;
    }

    for (i = 0; i < thread_nr; i++) {
        if (pthread_create(&synthesize_threads[i], NULL,
                   synthesize_threads_worker, &args[i]))
            goto out_join;
    }
    err = 0;
out_join:
    for (i = 0; i < thread_nr; i++)
        pthread_join(synthesize_threads[i], NULL);
    free(args);
free_threads:
    free(synthesize_threads);
free_dirent:
    for (i = 0; i < n; i++)
        free(dirent[i]);
    free(dirent);

    return err;
}

struct process_symbol_args {
    const char *name;
    u64    start;
};

static int find_symbol_cb(void *arg, const char *name, char type,
              u64 start)
{
    struct process_symbol_args *args = arg;

    /*
     * Must be a function or at least an alias, as in PARISC64, where "_text" is
     * an 'A' to the same address as "_stext".
     */
    if (!(kallsyms__is_function(type) ||
          type == 'A') || strcmp(name, args->name))
        return 0;

    args->start = start;
    return 1;
}

int kallsyms__get_function_start(const char *kallsyms_filename,
                 const char *symbol_name, u64 *addr)
{
    struct process_symbol_args args = { .name = symbol_name, };

    if (kallsyms__parse(kallsyms_filename, &args, find_symbol_cb) <= 0)
        return -1;

    *addr = args.start;
    return 0;
}

int __weak perf_event__synthesize_extra_kmaps(struct perf_tool *tool __maybe_unused,
                          perf_event__handler_t process __maybe_unused,
                          struct machine *machine __maybe_unused)
{
    return 0;
}

static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
                        perf_event__handler_t process,
                        struct machine *machine)
{
    size_t size;
    struct map *map = machine__kernel_map(machine);
    struct kmap *kmap;
    int err;
    union perf_event *event;

    if (symbol_conf.kptr_restrict)
        return -1;
    if (map == NULL)
        return -1;

    /*
     * We should get this from /sys/kernel/sections/.text, but till that is
     * available use this, and after it is use this as a fallback for older
     * kernels.
     */
    event = zalloc((sizeof(event->mmap) + machine->id_hdr_size));
    if (event == NULL) {
        pr_debug("Not enough memory synthesizing mmap event "
             "for kernel modules\n");
        return -1;
    }

    if (machine__is_host(machine)) {
        /*
         * kernel uses PERF_RECORD_MISC_USER for user space maps,
         * see kernel/perf_event.c __perf_event_mmap
         */
        event->header.misc = PERF_RECORD_MISC_KERNEL;
    } else {
        event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
    }

    kmap = map__kmap(map);
    size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
            "%s%s", machine->mmap_name, kmap->ref_reloc_sym->name) + 1;
    size = PERF_ALIGN(size, sizeof(u64));
    event->mmap.header.type = PERF_RECORD_MMAP;
    event->mmap.header.size = (sizeof(event->mmap) -
            (sizeof(event->mmap.filename) - size) + machine->id_hdr_size);
    event->mmap.pgoff = kmap->ref_reloc_sym->addr;
    event->mmap.start = map->start;
    event->mmap.len   = map->end - event->mmap.start;
    event->mmap.pid   = machine->pid;

    err = perf_tool__process_synth_event(tool, event, machine, process);
    free(event);

    return err;
}

int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
                       perf_event__handler_t process,
                       struct machine *machine)
{
    int err;

    err = __perf_event__synthesize_kernel_mmap(tool, process, machine);
    if (err < 0)
        return err;

    return perf_event__synthesize_extra_kmaps(tool, process, machine);
}

int perf_event__synthesize_thread_map2(struct perf_tool *tool,
                      struct thread_map *threads,
                      perf_event__handler_t process,
                      struct machine *machine)
{
    union perf_event *event;
    int i, err, size;

    size  = sizeof(event->thread_map);
    size += threads->nr * sizeof(event->thread_map.entries[0]);

    event = zalloc(size);
    if (!event)
        return -ENOMEM;

    event->header.type = PERF_RECORD_THREAD_MAP;
    event->header.size = size;
    event->thread_map.nr = threads->nr;

    for (i = 0; i < threads->nr; i++) {
        struct thread_map_event_entry *entry = &event->thread_map.entries[i];
        char *comm = thread_map__comm(threads, i);

        if (!comm)
            comm = (char *) "";

        entry->pid = thread_map__pid(threads, i);
        strncpy((char *) &entry->comm, comm, sizeof(entry->comm));
    }

    err = process(tool, event, NULL, machine);

    free(event);
    return err;
}

static void synthesize_cpus(struct cpu_map_entries *cpus,
                struct cpu_map *map)
{
    int i;

    cpus->nr = map->nr;

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

static void synthesize_mask(struct cpu_map_mask *mask,
                struct cpu_map *map, int max)
{
    int i;

    mask->nr = BITS_TO_LONGS(max);
    mask->long_size = sizeof(long);

    for (i = 0; i < map->nr; i++)
        set_bit(map->map[i], mask->mask);
}

static size_t cpus_size(struct cpu_map *map)
{
    return sizeof(struct cpu_map_entries) + map->nr * sizeof(u16);
}

static size_t mask_size(struct cpu_map *map, int *max)
{
    int i;

    *max = 0;

    for (i = 0; i < map->nr; i++) {
        /* bit possition of the cpu is + 1 */
        int bit = map->map[i] + 1;

        if (bit > *max)
            *max = bit;
    }

    return sizeof(struct cpu_map_mask) + BITS_TO_LONGS(*max) * sizeof(long);
}

void *cpu_map_data__alloc(struct cpu_map *map, size_t *size, u16 *type, int *max)
{
    size_t size_cpus, size_mask;
    bool is_dummy = cpu_map__empty(map);

    /*
     * Both array and mask data have variable size based
     * on the number of cpus and their actual values.
     * The size of the 'struct cpu_map_data' is:
     *
     *   array = size of 'struct cpu_map_entries' +
     *           number of cpus * sizeof(u64)
     *
     *   mask  = size of 'struct cpu_map_mask' +
     *           maximum cpu bit converted to size of longs
     *
     * and finaly + the size of 'struct cpu_map_data'.
     */
    size_cpus = cpus_size(map);
    size_mask = mask_size(map, max);

    if (is_dummy || (size_cpus < size_mask)) {
        *size += size_cpus;
        *type  = PERF_CPU_MAP__CPUS;
    } else {
        *size += size_mask;
        *type  = PERF_CPU_MAP__MASK;
    }

    *size += sizeof(struct cpu_map_data);
    return zalloc(*size);
}

void cpu_map_data__synthesize(struct cpu_map_data *data, struct cpu_map *map,
                  u16 type, int max)
{
    data->type = type;

    switch (type) {
    case PERF_CPU_MAP__CPUS:
        synthesize_cpus((struct cpu_map_entries *) data->data, map);
        break;
    case PERF_CPU_MAP__MASK:
        synthesize_mask((struct cpu_map_mask *) data->data, map, max);
    default:
        break;
    };
}

static struct cpu_map_event* cpu_map_event__new(struct cpu_map *map)
{
    size_t size = sizeof(struct cpu_map_event);
    struct cpu_map_event *event;
    int max;
    u16 type;

    event = cpu_map_data__alloc(map, &size, &type, &max);
    if (!event)
        return NULL;

    event->header.type = PERF_RECORD_CPU_MAP;
    event->header.size = size;
    event->data.type   = type;

    cpu_map_data__synthesize(&event->data, map, type, max);
    return event;
}

int perf_event__synthesize_cpu_map(struct perf_tool *tool,
                   struct cpu_map *map,
                   perf_event__handler_t process,
                   struct machine *machine)
{
    struct cpu_map_event *event;
    int err;

    event = cpu_map_event__new(map);
    if (!event)
        return -ENOMEM;

    err = process(tool, (union perf_event *) event, NULL, machine);

    free(event);
    return err;
}

int perf_event__synthesize_stat_config(struct perf_tool *tool,
                       struct perf_stat_config *config,
                       perf_event__handler_t process,
                       struct machine *machine)
{
    struct stat_config_event *event;
    int size, i = 0, err;

    size  = sizeof(*event);
    size += (PERF_STAT_CONFIG_TERM__MAX * sizeof(event->data[0]));

    event = zalloc(size);
    if (!event)
        return -ENOMEM;

    event->header.type = PERF_RECORD_STAT_CONFIG;
    event->header.size = size;
    event->nr          = PERF_STAT_CONFIG_TERM__MAX;

#define ADD(__term, __val)                  \
    event->data[i].tag = PERF_STAT_CONFIG_TERM__##__term;   \
    event->data[i].val = __val;             \
    i++;

    ADD(AGGR_MODE,  config->aggr_mode)
    ADD(INTERVAL,   config->interval)
    ADD(SCALE,  config->scale)

    WARN_ONCE(i != PERF_STAT_CONFIG_TERM__MAX,
          "stat config terms unbalanced\n");
#undef ADD

    err = process(tool, (union perf_event *) event, NULL, machine);

    free(event);
    return err;
}

int perf_event__synthesize_stat(struct perf_tool *tool,
                u32 cpu, u32 thread, u64 id,
                struct perf_counts_values *count,
                perf_event__handler_t process,
                struct machine *machine)
{
    struct stat_event event;

    event.header.type = PERF_RECORD_STAT;
    event.header.size = sizeof(event);
    event.header.misc = 0;

    event.id        = id;
    event.cpu       = cpu;
    event.thread    = thread;
    event.val       = count->val;
    event.ena       = count->ena;
    event.run       = count->run;

    return process(tool, (union perf_event *) &event, NULL, machine);
}

int perf_event__synthesize_stat_round(struct perf_tool *tool,
                      u64 evtime, u64 type,
                      perf_event__handler_t process,
                      struct machine *machine)
{
    struct stat_round_event event;

    event.header.type = PERF_RECORD_STAT_ROUND;
    event.header.size = sizeof(event);
    event.header.misc = 0;

    event.time = evtime;
    event.type = type;

    return process(tool, (union perf_event *) &event, NULL, machine);
}

void perf_event__read_stat_config(struct perf_stat_config *config,
                  struct stat_config_event *event)
{
    unsigned i;

    for (i = 0; i < event->nr; i++) {

        switch (event->data[i].tag) {
#define CASE(__term, __val)                 \
        case PERF_STAT_CONFIG_TERM__##__term:       \
            config->__val = event->data[i].val; \
            break;

        CASE(AGGR_MODE, aggr_mode)
        CASE(SCALE,     scale)
        CASE(INTERVAL,  interval)
#undef CASE
        default:
            pr_warning("unknown stat config term %" PRIu64 "\n",
                   event->data[i].tag);
        }
    }
}

size_t perf_event__fprintf_comm(union perf_event *event, FILE *fp)
{
    const char *s;

    if (event->header.misc & PERF_RECORD_MISC_COMM_EXEC)
        s = " exec";
    else
        s = "";

    return fprintf(fp, "%s: %s:%d/%d\n", s, event->comm.comm, event->comm.pid, event->comm.tid);
}

size_t perf_event__fprintf_namespaces(union perf_event *event, FILE *fp)
{
    size_t ret = 0;
    struct perf_ns_link_info *ns_link_info;
    u32 nr_namespaces, idx;

    ns_link_info = event->namespaces.link_info;
    nr_namespaces = event->namespaces.nr_namespaces;

    ret += fprintf(fp, " %d/%d - nr_namespaces: %u\n\t\t[",
               event->namespaces.pid,
               event->namespaces.tid,
               nr_namespaces);

    for (idx = 0; idx < nr_namespaces; idx++) {
        if (idx && (idx % 4 == 0))
            ret += fprintf(fp, "\n\t\t ");

        ret  += fprintf(fp, "%u/%s: %" PRIu64 "/%#" PRIx64 "%s", idx,
                perf_ns__name(idx), (u64)ns_link_info[idx].dev,
                (u64)ns_link_info[idx].ino,
                ((idx + 1) != nr_namespaces) ? ", " : "]\n");
    }

    return ret;
}

int perf_event__process_comm(struct perf_tool *tool __maybe_unused,
                 union perf_event *event,
                 struct perf_sample *sample,
                 struct machine *machine)
{
    return machine__process_comm_event(machine, event, sample);
}

int perf_event__process_namespaces(struct perf_tool *tool __maybe_unused,
                   union perf_event *event,
                   struct perf_sample *sample,
                   struct machine *machine)
{
    return machine__process_namespaces_event(machine, event, sample);
}

int perf_event__process_lost(struct perf_tool *tool __maybe_unused,
                 union perf_event *event,
                 struct perf_sample *sample,
                 struct machine *machine)
{
    return machine__process_lost_event(machine, event, sample);
}

int perf_event__process_aux(struct perf_tool *tool __maybe_unused,
                union perf_event *event,
                struct perf_sample *sample __maybe_unused,
                struct machine *machine)
{
    return machine__process_aux_event(machine, event);
}

int perf_event__process_itrace_start(struct perf_tool *tool __maybe_unused,
                     union perf_event *event,
                     struct perf_sample *sample __maybe_unused,
                     struct machine *machine)
{
    return machine__process_itrace_start_event(machine, event);
}

int perf_event__process_lost_samples(struct perf_tool *tool __maybe_unused,
                     union perf_event *event,
                     struct perf_sample *sample,
                     struct machine *machine)
{
    return machine__process_lost_samples_event(machine, event, sample);
}

int perf_event__process_switch(struct perf_tool *tool __maybe_unused,
                   union perf_event *event,
                   struct perf_sample *sample __maybe_unused,
                   struct machine *machine)
{
    return machine__process_switch_event(machine, event);
}

size_t perf_event__fprintf_mmap(union perf_event *event, FILE *fp)
{
    return fprintf(fp, " %d/%d: [%#" PRIx64 "(%#" PRIx64 ") @ %#" PRIx64 "]: %c %s\n",
               event->mmap.pid, event->mmap.tid, event->mmap.start,
               event->mmap.len, event->mmap.pgoff,
               (event->header.misc & PERF_RECORD_MISC_MMAP_DATA) ? 'r' : 'x',
               event->mmap.filename);
}

size_t perf_event__fprintf_mmap2(union perf_event *event, FILE *fp)
{
    return fprintf(fp, " %d/%d: [%#" PRIx64 "(%#" PRIx64 ") @ %#" PRIx64
               " %02x:%02x %"PRIu64" %"PRIu64"]: %c%c%c%c %s\n",
               event->mmap2.pid, event->mmap2.tid, event->mmap2.start,
               event->mmap2.len, event->mmap2.pgoff, event->mmap2.maj,
               event->mmap2.min, event->mmap2.ino,
               event->mmap2.ino_generation,
               (event->mmap2.prot & PROT_READ) ? 'r' : '-',
               (event->mmap2.prot & PROT_WRITE) ? 'w' : '-',
               (event->mmap2.prot & PROT_EXEC) ? 'x' : '-',
               (event->mmap2.flags & MAP_SHARED) ? 's' : 'p',
               event->mmap2.filename);
}

size_t perf_event__fprintf_thread_map(union perf_event *event, FILE *fp)
{
    struct thread_map *threads = thread_map__new_event(&event->thread_map);
    size_t ret;

    ret = fprintf(fp, " nr: ");

    if (threads)
        ret += thread_map__fprintf(threads, fp);
    else
        ret += fprintf(fp, "failed to get threads from event\n");

    thread_map__put(threads);
    return ret;
}

size_t perf_event__fprintf_cpu_map(union perf_event *event, FILE *fp)
{
    struct cpu_map *cpus = cpu_map__new_data(&event->cpu_map.data);
    size_t ret;

    ret = fprintf(fp, ": ");

    if (cpus)
        ret += cpu_map__fprintf(cpus, fp);
    else
        ret += fprintf(fp, "failed to get cpumap from event\n");

    cpu_map__put(cpus);
    return ret;
}

int perf_event__process_mmap(struct perf_tool *tool __maybe_unused,
                 union perf_event *event,
                 struct perf_sample *sample,
                 struct machine *machine)
{
    return machine__process_mmap_event(machine, event, sample);
}

int perf_event__process_mmap2(struct perf_tool *tool __maybe_unused,
                 union perf_event *event,
                 struct perf_sample *sample,
                 struct machine *machine)
{
    return machine__process_mmap2_event(machine, event, sample);
}

size_t perf_event__fprintf_task(union perf_event *event, FILE *fp)
{
    return fprintf(fp, "(%d:%d):(%d:%d)\n",
               event->fork.pid, event->fork.tid,
               event->fork.ppid, event->fork.ptid);
}

int perf_event__process_fork(struct perf_tool *tool __maybe_unused,
                 union perf_event *event,
                 struct perf_sample *sample,
                 struct machine *machine)
{
    return machine__process_fork_event(machine, event, sample);
}

int perf_event__process_exit(struct perf_tool *tool __maybe_unused,
                 union perf_event *event,
                 struct perf_sample *sample,
                 struct machine *machine)
{
    return machine__process_exit_event(machine, event, sample);
}

size_t perf_event__fprintf_aux(union perf_event *event, FILE *fp)
{
    return fprintf(fp, " offset: %#"PRIx64" size: %#"PRIx64" flags: %#"PRIx64" [%s%s%s]\n",
               event->aux.aux_offset, event->aux.aux_size,
               event->aux.flags,
               event->aux.flags & PERF_AUX_FLAG_TRUNCATED ? "T" : "",
               event->aux.flags & PERF_AUX_FLAG_OVERWRITE ? "O" : "",
               event->aux.flags & PERF_AUX_FLAG_PARTIAL   ? "P" : "");
}

size_t perf_event__fprintf_itrace_start(union perf_event *event, FILE *fp)
{
    return fprintf(fp, " pid: %u tid: %u\n",
               event->itrace_start.pid, event->itrace_start.tid);
}

size_t perf_event__fprintf_switch(union perf_event *event, FILE *fp)
{
    bool out = event->header.misc & PERF_RECORD_MISC_SWITCH_OUT;
    const char *in_out = !out ? "IN         " :
        !(event->header.misc & PERF_RECORD_MISC_SWITCH_OUT_PREEMPT) ?
                    "OUT        " : "OUT preempt";

    if (event->header.type == PERF_RECORD_SWITCH)
        return fprintf(fp, " %s\n", in_out);

    return fprintf(fp, " %s  %s pid/tid: %5u/%-5u\n",
               in_out, out ? "next" : "prev",
               event->context_switch.next_prev_pid,
               event->context_switch.next_prev_tid);
}

static size_t perf_event__fprintf_lost(union perf_event *event, FILE *fp)
{
    return fprintf(fp, " lost %" PRIu64 "\n", event->lost.lost);
}

size_t perf_event__fprintf(union perf_event *event, FILE *fp)
{
    size_t ret = fprintf(fp, "PERF_RECORD_%s",
                 perf_event__name(event->header.type));

    switch (event->header.type) {
    case PERF_RECORD_COMM:
        ret += perf_event__fprintf_comm(event, fp);
        break;
    case PERF_RECORD_FORK:
    case PERF_RECORD_EXIT:
        ret += perf_event__fprintf_task(event, fp);
        break;
    case PERF_RECORD_MMAP:
        ret += perf_event__fprintf_mmap(event, fp);
        break;
    case PERF_RECORD_NAMESPACES:
        ret += perf_event__fprintf_namespaces(event, fp);
        break;
    case PERF_RECORD_MMAP2:
        ret += perf_event__fprintf_mmap2(event, fp);
        break;
    case PERF_RECORD_AUX:
        ret += perf_event__fprintf_aux(event, fp);
        break;
    case PERF_RECORD_ITRACE_START:
        ret += perf_event__fprintf_itrace_start(event, fp);
        break;
    case PERF_RECORD_SWITCH:
    case PERF_RECORD_SWITCH_CPU_WIDE:
        ret += perf_event__fprintf_switch(event, fp);
        break;
    case PERF_RECORD_LOST:
        ret += perf_event__fprintf_lost(event, fp);
        break;
    default:
        ret += fprintf(fp, "\n");
    }

    return ret;
}

int perf_event__process(struct perf_tool *tool __maybe_unused,
            union perf_event *event,
            struct perf_sample *sample,
            struct machine *machine)
{
    return machine__process_event(machine, event, sample);
}

struct map *thread__find_map(struct thread *thread, u8 cpumode, u64 addr,
                 struct addr_location *al)
{
    struct map_groups *mg = thread->mg;
    struct machine *machine = mg->machine;
    bool load_map = false;

    al->machine = machine;
    al->thread = thread;
    al->addr = addr;
    al->cpumode = cpumode;
    al->filtered = 0;

    if (machine == NULL) {
        al->map = NULL;
        return NULL;
    }

    if (cpumode == PERF_RECORD_MISC_KERNEL && perf_host) {
        al->level = 'k';
        mg = &machine->kmaps;
        load_map = true;
    } else if (cpumode == PERF_RECORD_MISC_USER && perf_host) {
        al->level = '.';
    } else if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) {
        al->level = 'g';
        mg = &machine->kmaps;
        load_map = true;
    } else if (cpumode == PERF_RECORD_MISC_GUEST_USER && perf_guest) {
        al->level = 'u';
    } else {
        al->level = 'H';
        al->map = NULL;

        if ((cpumode == PERF_RECORD_MISC_GUEST_USER ||
            cpumode == PERF_RECORD_MISC_GUEST_KERNEL) &&
            !perf_guest)
            al->filtered |= (1 << HIST_FILTER__GUEST);
        if ((cpumode == PERF_RECORD_MISC_USER ||
            cpumode == PERF_RECORD_MISC_KERNEL) &&
            !perf_host)
            al->filtered |= (1 << HIST_FILTER__HOST);

        return NULL;
    }
try_again:
    al->map = map_groups__find(mg, al->addr);
    if (al->map == NULL) {
        /*
         * If this is outside of all known maps, and is a negative
         * address, try to look it up in the kernel dso, as it might be
         * a vsyscall or vdso (which executes in user-mode).
         *
         * XXX This is nasty, we should have a symbol list in the
         * "[vdso]" dso, but for now lets use the old trick of looking
         * in the whole kernel symbol list.
         */
        if (cpumode == PERF_RECORD_MISC_USER && machine &&
            mg != &machine->kmaps &&
            machine__kernel_ip(machine, al->addr)) {
            mg = &machine->kmaps;
            load_map = true;
            goto try_again;
        }
    } else {
        /*
         * Kernel maps might be changed when loading symbols so loading
         * must be done prior to using kernel maps.
         */
        if (load_map)
            map__load(al->map);
        al->addr = al->map->map_ip(al->map, al->addr);
    }

    return al->map;
}

struct symbol *thread__find_symbol(struct thread *thread, u8 cpumode,
                   u64 addr, struct addr_location *al)
{
    al->sym = NULL;
    if (thread__find_map(thread, cpumode, addr, al))
        al->sym = map__find_symbol(al->map, al->addr);
    return al->sym;
}

/*
 * Callers need to drop the reference to al->thread, obtained in
 * machine__findnew_thread()
 */
int machine__resolve(struct machine *machine, struct addr_location *al,
             struct perf_sample *sample)
{
    struct thread *thread = machine__findnew_thread(machine, sample->pid,
                            sample->tid);

    if (thread == NULL)
        return -1;

    dump_printf(" ... thread: %s:%d\n", thread__comm_str(thread), thread->tid);
    thread__find_map(thread, sample->cpumode, sample->ip, al);
    dump_printf(" ...... dso: %s\n",
            al->map ? al->map->dso->long_name :
            al->level == 'H' ? "[hypervisor]" : "<not found>");

    if (thread__is_filtered(thread))
        al->filtered |= (1 << HIST_FILTER__THREAD);

    al->sym = NULL;
    al->cpu = sample->cpu;
    al->socket = -1;
    al->srcline = NULL;

    if (al->cpu >= 0) {
        struct perf_env *env = machine->env;

        if (env && env->cpu)
            al->socket = env->cpu[al->cpu].socket_id;
    }

    if (al->map) {
        struct dso *dso = al->map->dso;

        if (symbol_conf.dso_list &&
            (!dso || !(strlist__has_entry(symbol_conf.dso_list,
                          dso->short_name) ||
                   (dso->short_name != dso->long_name &&
                strlist__has_entry(symbol_conf.dso_list,
                           dso->long_name))))) {
            al->filtered |= (1 << HIST_FILTER__DSO);
        }

        al->sym = map__find_symbol(al->map, al->addr);
    }

    if (symbol_conf.sym_list &&
        (!al->sym || !strlist__has_entry(symbol_conf.sym_list,
                        al->sym->name))) {
        al->filtered |= (1 << HIST_FILTER__SYMBOL);
    }

    return 0;
}

/*
 * The preprocess_sample method will return with reference counts for the
 * in it, when done using (and perhaps getting ref counts if needing to
 * keep a pointer to one of those entries) it must be paired with
 * addr_location__put(), so that the refcounts can be decremented.
 */
void addr_location__put(struct addr_location *al)
{
    thread__zput(al->thread);
}

bool is_bts_event(struct perf_event_attr *attr)
{
    return attr->type == PERF_TYPE_HARDWARE &&
           (attr->config & PERF_COUNT_HW_BRANCH_INSTRUCTIONS) &&
           attr->sample_period == 1;
}

bool sample_addr_correlates_sym(struct perf_event_attr *attr)
{
    if (attr->type == PERF_TYPE_SOFTWARE &&
        (attr->config == PERF_COUNT_SW_PAGE_FAULTS ||
         attr->config == PERF_COUNT_SW_PAGE_FAULTS_MIN ||
         attr->config == PERF_COUNT_SW_PAGE_FAULTS_MAJ))
        return true;

    if (is_bts_event(attr))
        return true;

    return false;
}

void thread__resolve(struct thread *thread, struct addr_location *al,
             struct perf_sample *sample)
{
    thread__find_map(thread, sample->cpumode, sample->addr, al);

    al->cpu = sample->cpu;
    al->sym = NULL;

    if (al->map)
        al->sym = map__find_symbol(al->map, al->addr);
}