// SPDX-License-Identifier: GPL-2.0
#include "builtin.h"
#include "perf.h"
#include "perf-sys.h"

#include "util/cpumap.h"
#include "util/evlist.h"
#include "util/evsel.h"
#include "util/evsel_fprintf.h"
#include "util/symbol.h"
#include "util/thread.h"
#include "util/header.h"
#include "util/session.h"
#include "util/tool.h"
#include "util/cloexec.h"
#include "util/thread_map.h"
#include "util/color.h"
#include "util/stat.h"
#include "util/string2.h"
#include "util/callchain.h"
#include "util/time-utils.h"

#include <subcmd/pager.h>
#include <subcmd/parse-options.h>
#include "util/trace-event.h"

#include "util/debug.h"
#include "util/event.h"

#include <linux/kernel.h>
#include <linux/log2.h>
#include <linux/zalloc.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <inttypes.h>

#include <errno.h>
#include <semaphore.h>
#include <pthread.h>
#include <math.h>
#include <api/fs/fs.h>
#include <perf/cpumap.h>
#include <linux/time64.h>
#include <linux/err.h>

#include <linux/ctype.h>

#define PR_SET_NAME             15               /* Set process name */
#define MAX_CPUS                4096
#define COMM_LEN                20
#define SYM_LEN                 129
#define MAX_PID                 1024000

struct sched_atom;

struct task_desc {
        unsigned long           nr;
        unsigned long           pid;
        char                    comm[COMM_LEN];

        unsigned long           nr_events;
        unsigned long           curr_event;
        struct sched_atom       **atoms;

        pthread_t               thread;
        sem_t                   sleep_sem;

        sem_t                   ready_for_work;
        sem_t                   work_done_sem;

        u64                     cpu_usage;
};

enum sched_event_type {
        SCHED_EVENT_RUN,
        SCHED_EVENT_SLEEP,
        SCHED_EVENT_WAKEUP,
        SCHED_EVENT_MIGRATION,
};

struct sched_atom {
        enum sched_event_type   type;
        int                     specific_wait;
        u64                     timestamp;
        u64                     duration;
        unsigned long           nr;
        sem_t                   *wait_sem;
        struct task_desc        *wakee;
};

#define TASK_STATE_TO_CHAR_STR "RSDTtZXxKWP"

/* task state bitmask, copied from include/linux/sched.h */
#define TASK_RUNNING            0
#define TASK_INTERRUPTIBLE      1
#define TASK_UNINTERRUPTIBLE    2
#define __TASK_STOPPED          4
#define __TASK_TRACED           8
/* in tsk->exit_state */
#define EXIT_DEAD               16
#define EXIT_ZOMBIE             32
#define EXIT_TRACE              (EXIT_ZOMBIE | EXIT_DEAD)
/* in tsk->state again */
#define TASK_DEAD               64
#define TASK_WAKEKILL           128
#define TASK_WAKING             256
#define TASK_PARKED             512

enum thread_state {
        THREAD_SLEEPING = 0,
        THREAD_WAIT_CPU,
        THREAD_SCHED_IN,
        THREAD_IGNORE
};

struct work_atom {
        struct list_head        list;
        enum thread_state       state;
        u64                     sched_out_time;
        u64                     wake_up_time;
        u64                     sched_in_time;
        u64                     runtime;
};

struct work_atoms {
        struct list_head        work_list;
        struct thread           *thread;
        struct rb_node          node;
        u64                     max_lat;
        u64                     max_lat_at;
        u64                     total_lat;
        u64                     nb_atoms;
        u64                     total_runtime;
        int                     num_merged;
};

typedef int (*sort_fn_t)(struct work_atoms *, struct work_atoms *);

struct perf_sched;

struct trace_sched_handler {
        int (*switch_event)(struct perf_sched *sched, struct evsel *evsel,
                            struct perf_sample *sample, struct machine *machine);

        int (*runtime_event)(struct perf_sched *sched, struct evsel *evsel,
                             struct perf_sample *sample, struct machine *machine);

        int (*wakeup_event)(struct perf_sched *sched, struct evsel *evsel,
                            struct perf_sample *sample, struct machine *machine);

        /* PERF_RECORD_FORK event, not sched_process_fork tracepoint */
        int (*fork_event)(struct perf_sched *sched, union perf_event *event,
                          struct machine *machine);

        int (*migrate_task_event)(struct perf_sched *sched,
                                  struct evsel *evsel,
                                  struct perf_sample *sample,
                                  struct machine *machine);
};

#define COLOR_PIDS PERF_COLOR_BLUE
#define COLOR_CPUS PERF_COLOR_BG_RED

struct perf_sched_map {
        DECLARE_BITMAP(comp_cpus_mask, MAX_CPUS);
        int                     *comp_cpus;
        bool                     comp;
        struct perf_thread_map *color_pids;
        const char              *color_pids_str;
        struct perf_cpu_map     *color_cpus;
        const char              *color_cpus_str;
        struct perf_cpu_map     *cpus;
        const char              *cpus_str;
};

struct perf_sched {
        struct perf_tool tool;
        const char       *sort_order;
        unsigned long    nr_tasks;
        struct task_desc **pid_to_task;
        struct task_desc **tasks;
        const struct trace_sched_handler *tp_handler;
        pthread_mutex_t  start_work_mutex;
        pthread_mutex_t  work_done_wait_mutex;
        int              profile_cpu;
/*
 * Track the current task - that way we can know whether there's any
 * weird events, such as a task being switched away that is not current.
 */
        int              max_cpu;
        u32              curr_pid[MAX_CPUS];
        struct thread    *curr_thread[MAX_CPUS];
        char             next_shortname1;
        char             next_shortname2;
        unsigned int     replay_repeat;
        unsigned long    nr_run_events;
        unsigned long    nr_sleep_events;
        unsigned long    nr_wakeup_events;
        unsigned long    nr_sleep_corrections;
        unsigned long    nr_run_events_optimized;
        unsigned long    targetless_wakeups;
        unsigned long    multitarget_wakeups;
        unsigned long    nr_runs;
        unsigned long    nr_timestamps;
        unsigned long    nr_unordered_timestamps;
        unsigned long    nr_context_switch_bugs;
        unsigned long    nr_events;
        unsigned long    nr_lost_chunks;
        unsigned long    nr_lost_events;
        u64              run_measurement_overhead;
        u64              sleep_measurement_overhead;
        u64              start_time;
        u64              cpu_usage;
        u64              runavg_cpu_usage;
        u64              parent_cpu_usage;
        u64              runavg_parent_cpu_usage;
        u64              sum_runtime;
        u64              sum_fluct;
        u64              run_avg;
        u64              all_runtime;
        u64              all_count;
        u64              cpu_last_switched[MAX_CPUS];
        struct rb_root_cached atom_root, sorted_atom_root, merged_atom_root;
        struct list_head sort_list, cmp_pid;
        bool force;
        bool skip_merge;
        struct perf_sched_map map;

        /* options for timehist command */
        bool            summary;
        bool            summary_only;
        bool            idle_hist;
        bool            show_callchain;
        unsigned int    max_stack;
        bool            show_cpu_visual;
        bool            show_wakeups;
        bool            show_next;
        bool            show_migrations;
        bool            show_state;
        u64             skipped_samples;
        const char      *time_str;
        struct perf_time_interval ptime;
        struct perf_time_interval hist_time;
};

/* per thread run time data */
struct thread_runtime {
        u64 last_time;      /* time of previous sched in/out event */
        u64 dt_run;         /* run time */
        u64 dt_sleep;       /* time between CPU access by sleep (off cpu) */
        u64 dt_iowait;      /* time between CPU access by iowait (off cpu) */
        u64 dt_preempt;     /* time between CPU access by preempt (off cpu) */
        u64 dt_delay;       /* time between wakeup and sched-in */
        u64 ready_to_run;   /* time of wakeup */

        struct stats run_stats;
        u64 total_run_time;
        u64 total_sleep_time;
        u64 total_iowait_time;
        u64 total_preempt_time;
        u64 total_delay_time;

        int last_state;

        char shortname[3];
        bool comm_changed;

        u64 migrations;
};

/* per event run time data */
struct evsel_runtime {
        u64 *last_time; /* time this event was last seen per cpu */
        u32 ncpu;       /* highest cpu slot allocated */
};

/* per cpu idle time data */
struct idle_thread_runtime {
        struct thread_runtime   tr;
        struct thread           *last_thread;
        struct rb_root_cached   sorted_root;
        struct callchain_root   callchain;
        struct callchain_cursor cursor;
};

/* track idle times per cpu */
static struct thread **idle_threads;
static int idle_max_cpu;
static char idle_comm[] = "<idle>";

static u64 get_nsecs(void)
{
        struct timespec ts;

        clock_gettime(CLOCK_MONOTONIC, &ts);

        return ts.tv_sec * NSEC_PER_SEC + ts.tv_nsec;
}

static void burn_nsecs(struct perf_sched *sched, u64 nsecs)
{
        u64 T0 = get_nsecs(), T1;

        do {
                T1 = get_nsecs();
        } while (T1 + sched->run_measurement_overhead < T0 + nsecs);
}

static void sleep_nsecs(u64 nsecs)
{
        struct timespec ts;

        ts.tv_nsec = nsecs % 999999999;
        ts.tv_sec = nsecs / 999999999;

        nanosleep(&ts, NULL);
}

static void calibrate_run_measurement_overhead(struct perf_sched *sched)
{
        u64 T0, T1, delta, min_delta = NSEC_PER_SEC;
        int i;

        for (i = 0; i < 10; i++) {
                T0 = get_nsecs();
                burn_nsecs(sched, 0);
                T1 = get_nsecs();
                delta = T1-T0;
                min_delta = min(min_delta, delta);
        }
        sched->run_measurement_overhead = min_delta;

        printf("run measurement overhead: %" PRIu64 " nsecs\n", min_delta);
}

static void calibrate_sleep_measurement_overhead(struct perf_sched *sched)
{
        u64 T0, T1, delta, min_delta = NSEC_PER_SEC;
        int i;

        for (i = 0; i < 10; i++) {
                T0 = get_nsecs();
                sleep_nsecs(10000);
                T1 = get_nsecs();
                delta = T1-T0;
                min_delta = min(min_delta, delta);
        }
        min_delta -= 10000;
        sched->sleep_measurement_overhead = min_delta;

        printf("sleep measurement overhead: %" PRIu64 " nsecs\n", min_delta);
}

static struct sched_atom *
get_new_event(struct task_desc *task, u64 timestamp)
{
        struct sched_atom *event = zalloc(sizeof(*event));
        unsigned long idx = task->nr_events;
        size_t size;

        event->timestamp = timestamp;
        event->nr = idx;

        task->nr_events++;
        size = sizeof(struct sched_atom *) * task->nr_events;
        task->atoms = realloc(task->atoms, size);
        BUG_ON(!task->atoms);

        task->atoms[idx] = event;

        return event;
}

static struct sched_atom *last_event(struct task_desc *task)
{
        if (!task->nr_events)
                return NULL;

        return task->atoms[task->nr_events - 1];
}

static void add_sched_event_run(struct perf_sched *sched, struct task_desc *task,
                                u64 timestamp, u64 duration)
{
        struct sched_atom *event, *curr_event = last_event(task);

        /*
         * optimize an existing RUN event by merging this one
         * to it:
         */
        if (curr_event && curr_event->type == SCHED_EVENT_RUN) {
                sched->nr_run_events_optimized++;
                curr_event->duration += duration;
                return;
        }

        event = get_new_event(task, timestamp);

        event->type = SCHED_EVENT_RUN;
        event->duration = duration;

        sched->nr_run_events++;
}

static void add_sched_event_wakeup(struct perf_sched *sched, struct task_desc *task,
                                   u64 timestamp, struct task_desc *wakee)
{
        struct sched_atom *event, *wakee_event;

        event = get_new_event(task, timestamp);
        event->type = SCHED_EVENT_WAKEUP;
        event->wakee = wakee;

        wakee_event = last_event(wakee);
        if (!wakee_event || wakee_event->type != SCHED_EVENT_SLEEP) {
                sched->targetless_wakeups++;
                return;
        }
        if (wakee_event->wait_sem) {
                sched->multitarget_wakeups++;
                return;
        }

        wakee_event->wait_sem = zalloc(sizeof(*wakee_event->wait_sem));
        sem_init(wakee_event->wait_sem, 0, 0);
        wakee_event->specific_wait = 1;
        event->wait_sem = wakee_event->wait_sem;

        sched->nr_wakeup_events++;
}

static void add_sched_event_sleep(struct perf_sched *sched, struct task_desc *task,
                                  u64 timestamp, u64 task_state __maybe_unused)
{
        struct sched_atom *event = get_new_event(task, timestamp);

        event->type = SCHED_EVENT_SLEEP;

        sched->nr_sleep_events++;
}

static struct task_desc *register_pid(struct perf_sched *sched,
                                      unsigned long pid, const char *comm)
{
        struct task_desc *task;
        static int pid_max;

        if (sched->pid_to_task == NULL) {
                if (sysctl__read_int("kernel/pid_max", &pid_max) < 0)
                        pid_max = MAX_PID;
                BUG_ON((sched->pid_to_task = calloc(pid_max, sizeof(struct task_desc *))) == NULL);
        }
        if (pid >= (unsigned long)pid_max) {
                BUG_ON((sched->pid_to_task = realloc(sched->pid_to_task, (pid + 1) *
                        sizeof(struct task_desc *))) == NULL);
                while (pid >= (unsigned long)pid_max)
                        sched->pid_to_task[pid_max++] = NULL;
        }

        task = sched->pid_to_task[pid];

        if (task)
                return task;

        task = zalloc(sizeof(*task));
        task->pid = pid;
        task->nr = sched->nr_tasks;
        strcpy(task->comm, comm);
        /*
         * every task starts in sleeping state - this gets ignored
         * if there's no wakeup pointing to this sleep state:
         */
        add_sched_event_sleep(sched, task, 0, 0);

        sched->pid_to_task[pid] = task;
        sched->nr_tasks++;
        sched->tasks = realloc(sched->tasks, sched->nr_tasks * sizeof(struct task_desc *));
        BUG_ON(!sched->tasks);
        sched->tasks[task->nr] = task;

        if (verbose > 0)
                printf("registered task #%ld, PID %ld (%s)\n", sched->nr_tasks, pid, comm);

        return task;
}


static void print_task_traces(struct perf_sched *sched)
{
        struct task_desc *task;
        unsigned long i;

        for (i = 0; i < sched->nr_tasks; i++) {
                task = sched->tasks[i];
                printf("task %6ld (%20s:%10ld), nr_events: %ld\n",
                        task->nr, task->comm, task->pid, task->nr_events);
        }
}

static void add_cross_task_wakeups(struct perf_sched *sched)
{
        struct task_desc *task1, *task2;
        unsigned long i, j;

        for (i = 0; i < sched->nr_tasks; i++) {
                task1 = sched->tasks[i];
                j = i + 1;
                if (j == sched->nr_tasks)
                        j = 0;
                task2 = sched->tasks[j];
                add_sched_event_wakeup(sched, task1, 0, task2);
        }
}

static void perf_sched__process_event(struct perf_sched *sched,
                                      struct sched_atom *atom)
{
        int ret = 0;

        switch (atom->type) {
                case SCHED_EVENT_RUN:
                        burn_nsecs(sched, atom->duration);
                        break;
                case SCHED_EVENT_SLEEP:
                        if (atom->wait_sem)
                                ret = sem_wait(atom->wait_sem);
                        BUG_ON(ret);
                        break;
                case SCHED_EVENT_WAKEUP:
                        if (atom->wait_sem)
                                ret = sem_post(atom->wait_sem);
                        BUG_ON(ret);
                        break;
                case SCHED_EVENT_MIGRATION:
                        break;
                default:
                        BUG_ON(1);
        }
}

static u64 get_cpu_usage_nsec_parent(void)
{
        struct rusage ru;
        u64 sum;
        int err;

        err = getrusage(RUSAGE_SELF, &ru);
        BUG_ON(err);

        sum =  ru.ru_utime.tv_sec * NSEC_PER_SEC + ru.ru_utime.tv_usec * NSEC_PER_USEC;
        sum += ru.ru_stime.tv_sec * NSEC_PER_SEC + ru.ru_stime.tv_usec * NSEC_PER_USEC;

        return sum;
}

static int self_open_counters(struct perf_sched *sched, unsigned long cur_task)
{
        struct perf_event_attr attr;
        char sbuf[STRERR_BUFSIZE], info[STRERR_BUFSIZE];
        int fd;
        struct rlimit limit;
        bool need_privilege = false;

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

        attr.type = PERF_TYPE_SOFTWARE;
        attr.config = PERF_COUNT_SW_TASK_CLOCK;

force_again:
        fd = sys_perf_event_open(&attr, 0, -1, -1,
                                 perf_event_open_cloexec_flag());

        if (fd < 0) {
                if (errno == EMFILE) {
                        if (sched->force) {
                                BUG_ON(getrlimit(RLIMIT_NOFILE, &limit) == -1);
                                limit.rlim_cur += sched->nr_tasks - cur_task;
                                if (limit.rlim_cur > limit.rlim_max) {
                                        limit.rlim_max = limit.rlim_cur;
                                        need_privilege = true;
                                }
                                if (setrlimit(RLIMIT_NOFILE, &limit) == -1) {
                                        if (need_privilege && errno == EPERM)
                                                strcpy(info, "Need privilege\n");
                                } else
                                        goto force_again;
                        } else
                                strcpy(info, "Have a try with -f option\n");
                }
                pr_err("Error: sys_perf_event_open() syscall returned "
                       "with %d (%s)\n%s", fd,
                       str_error_r(errno, sbuf, sizeof(sbuf)), info);
                exit(EXIT_FAILURE);
        }
        return fd;
}

static u64 get_cpu_usage_nsec_self(int fd)
{
        u64 runtime;
        int ret;

        ret = read(fd, &runtime, sizeof(runtime));
        BUG_ON(ret != sizeof(runtime));

        return runtime;
}

struct sched_thread_parms {
        struct task_desc  *task;
        struct perf_sched *sched;
        int fd;
};

static void *thread_func(void *ctx)
{
        struct sched_thread_parms *parms = ctx;
        struct task_desc *this_task = parms->task;
        struct perf_sched *sched = parms->sched;
        u64 cpu_usage_0, cpu_usage_1;
        unsigned long i, ret;
        char comm2[22];
        int fd = parms->fd;

        zfree(&parms);

        sprintf(comm2, ":%s", this_task->comm);
        prctl(PR_SET_NAME, comm2);
        if (fd < 0)
                return NULL;
again:
        ret = sem_post(&this_task->ready_for_work);
        BUG_ON(ret);
        ret = pthread_mutex_lock(&sched->start_work_mutex);
        BUG_ON(ret);
        ret = pthread_mutex_unlock(&sched->start_work_mutex);
        BUG_ON(ret);

        cpu_usage_0 = get_cpu_usage_nsec_self(fd);

        for (i = 0; i < this_task->nr_events; i++) {
                this_task->curr_event = i;
                perf_sched__process_event(sched, this_task->atoms[i]);
        }

        cpu_usage_1 = get_cpu_usage_nsec_self(fd);
        this_task->cpu_usage = cpu_usage_1 - cpu_usage_0;
        ret = sem_post(&this_task->work_done_sem);
        BUG_ON(ret);

        ret = pthread_mutex_lock(&sched->work_done_wait_mutex);
        BUG_ON(ret);
        ret = pthread_mutex_unlock(&sched->work_done_wait_mutex);
        BUG_ON(ret);

        goto again;
}

static void create_tasks(struct perf_sched *sched)
{
        struct task_desc *task;
        pthread_attr_t attr;
        unsigned long i;
        int err;

        err = pthread_attr_init(&attr);
        BUG_ON(err);
        err = pthread_attr_setstacksize(&attr,
                        (size_t) max(16 * 1024, PTHREAD_STACK_MIN));
        BUG_ON(err);
        err = pthread_mutex_lock(&sched->start_work_mutex);
        BUG_ON(err);
        err = pthread_mutex_lock(&sched->work_done_wait_mutex);
        BUG_ON(err);
        for (i = 0; i < sched->nr_tasks; i++) {
                struct sched_thread_parms *parms = malloc(sizeof(*parms));
                BUG_ON(parms == NULL);
                parms->task = task = sched->tasks[i];
                parms->sched = sched;
                parms->fd = self_open_counters(sched, i);
                sem_init(&task->sleep_sem, 0, 0);
                sem_init(&task->ready_for_work, 0, 0);
                sem_init(&task->work_done_sem, 0, 0);
                task->curr_event = 0;
                err = pthread_create(&task->thread, &attr, thread_func, parms);
                BUG_ON(err);
        }
}

static void wait_for_tasks(struct perf_sched *sched)
{
        u64 cpu_usage_0, cpu_usage_1;
        struct task_desc *task;
        unsigned long i, ret;

        sched->start_time = get_nsecs();
        sched->cpu_usage = 0;
        pthread_mutex_unlock(&sched->work_done_wait_mutex);

        for (i = 0; i < sched->nr_tasks; i++) {
                task = sched->tasks[i];
                ret = sem_wait(&task->ready_for_work);
                BUG_ON(ret);
                sem_init(&task->ready_for_work, 0, 0);
        }
        ret = pthread_mutex_lock(&sched->work_done_wait_mutex);
        BUG_ON(ret);

        cpu_usage_0 = get_cpu_usage_nsec_parent();

        pthread_mutex_unlock(&sched->start_work_mutex);

        for (i = 0; i < sched->nr_tasks; i++) {
                task = sched->tasks[i];
                ret = sem_wait(&task->work_done_sem);
                BUG_ON(ret);
                sem_init(&task->work_done_sem, 0, 0);
                sched->cpu_usage += task->cpu_usage;
                task->cpu_usage = 0;
        }

        cpu_usage_1 = get_cpu_usage_nsec_parent();
        if (!sched->runavg_cpu_usage)
                sched->runavg_cpu_usage = sched->cpu_usage;
        sched->runavg_cpu_usage = (sched->runavg_cpu_usage * (sched->replay_repeat - 1) + sched->cpu_usage) / sched->replay_repeat;

        sched->parent_cpu_usage = cpu_usage_1 - cpu_usage_0;
        if (!sched->runavg_parent_cpu_usage)
                sched->runavg_parent_cpu_usage = sched->parent_cpu_usage;
        sched->runavg_parent_cpu_usage = (sched->runavg_parent_cpu_usage * (sched->replay_repeat - 1) +
                                         sched->parent_cpu_usage)/sched->replay_repeat;

        ret = pthread_mutex_lock(&sched->start_work_mutex);
        BUG_ON(ret);

        for (i = 0; i < sched->nr_tasks; i++) {
                task = sched->tasks[i];
                sem_init(&task->sleep_sem, 0, 0);
                task->curr_event = 0;
        }
}

static void run_one_test(struct perf_sched *sched)
{
        u64 T0, T1, delta, avg_delta, fluct;

        T0 = get_nsecs();
        wait_for_tasks(sched);
        T1 = get_nsecs();

        delta = T1 - T0;
        sched->sum_runtime += delta;
        sched->nr_runs++;

        avg_delta = sched->sum_runtime / sched->nr_runs;
        if (delta < avg_delta)
                fluct = avg_delta - delta;
        else
                fluct = delta - avg_delta;
        sched->sum_fluct += fluct;
        if (!sched->run_avg)
                sched->run_avg = delta;
        sched->run_avg = (sched->run_avg * (sched->replay_repeat - 1) + delta) / sched->replay_repeat;

        printf("#%-3ld: %0.3f, ", sched->nr_runs, (double)delta / NSEC_PER_MSEC);

        printf("ravg: %0.2f, ", (double)sched->run_avg / NSEC_PER_MSEC);

        printf("cpu: %0.2f / %0.2f",
                (double)sched->cpu_usage / NSEC_PER_MSEC, (double)sched->runavg_cpu_usage / NSEC_PER_MSEC);

#if 0
        /*
         * rusage statistics done by the parent, these are less
         * accurate than the sched->sum_exec_runtime based statistics:
         */
        printf(" [%0.2f / %0.2f]",
                (double)sched->parent_cpu_usage / NSEC_PER_MSEC,
                (double)sched->runavg_parent_cpu_usage / NSEC_PER_MSEC);
#endif

        printf("\n");

        if (sched->nr_sleep_corrections)
                printf(" (%ld sleep corrections)\n", sched->nr_sleep_corrections);
        sched->nr_sleep_corrections = 0;
}

static void test_calibrations(struct perf_sched *sched)
{
        u64 T0, T1;

        T0 = get_nsecs();
        burn_nsecs(sched, NSEC_PER_MSEC);
        T1 = get_nsecs();

        printf("the run test took %" PRIu64 " nsecs\n", T1 - T0);

        T0 = get_nsecs();
        sleep_nsecs(NSEC_PER_MSEC);
        T1 = get_nsecs();

        printf("the sleep test took %" PRIu64 " nsecs\n", T1 - T0);
}

static int
replay_wakeup_event(struct perf_sched *sched,
                    struct evsel *evsel, struct perf_sample *sample,
                    struct machine *machine __maybe_unused)
{
        const char *comm = perf_evsel__strval(evsel, sample, "comm");
        const u32 pid    = perf_evsel__intval(evsel, sample, "pid");
        struct task_desc *waker, *wakee;

        if (verbose > 0) {
                printf("sched_wakeup event %p\n", evsel);

                printf(" ... pid %d woke up %s/%d\n", sample->tid, comm, pid);
        }

        waker = register_pid(sched, sample->tid, "<unknown>");
        wakee = register_pid(sched, pid, comm);

        add_sched_event_wakeup(sched, waker, sample->time, wakee);
        return 0;
}

static int replay_switch_event(struct perf_sched *sched,
                               struct evsel *evsel,
                               struct perf_sample *sample,
                               struct machine *machine __maybe_unused)
{
        const char *prev_comm  = perf_evsel__strval(evsel, sample, "prev_comm"),
                   *next_comm  = perf_evsel__strval(evsel, sample, "next_comm");
        const u32 prev_pid = perf_evsel__intval(evsel, sample, "prev_pid"),
                  next_pid = perf_evsel__intval(evsel, sample, "next_pid");
        const u64 prev_state = perf_evsel__intval(evsel, sample, "prev_state");
        struct task_desc *prev, __maybe_unused *next;
        u64 timestamp0, timestamp = sample->time;
        int cpu = sample->cpu;
        s64 delta;

        if (verbose > 0)
                printf("sched_switch event %p\n", evsel);

        if (cpu >= MAX_CPUS || cpu < 0)
                return 0;

        timestamp0 = sched->cpu_last_switched[cpu];
        if (timestamp0)
                delta = timestamp - timestamp0;
        else
                delta = 0;

        if (delta < 0) {
                pr_err("hm, delta: %" PRIu64 " < 0 ?\n", delta);
                return -1;
        }

        pr_debug(" ... switch from %s/%d to %s/%d [ran %" PRIu64 " nsecs]\n",
                 prev_comm, prev_pid, next_comm, next_pid, delta);

        prev = register_pid(sched, prev_pid, prev_comm);
        next = register_pid(sched, next_pid, next_comm);

        sched->cpu_last_switched[cpu] = timestamp;

        add_sched_event_run(sched, prev, timestamp, delta);
        add_sched_event_sleep(sched, prev, timestamp, prev_state);

        return 0;
}

static int replay_fork_event(struct perf_sched *sched,
                             union perf_event *event,
                             struct machine *machine)
{
        struct thread *child, *parent;

        child = machine__findnew_thread(machine, event->fork.pid,
                                        event->fork.tid);
        parent = machine__findnew_thread(machine, event->fork.ppid,
                                         event->fork.ptid);

        if (child == NULL || parent == NULL) {
                pr_debug("thread does not exist on fork event: child %p, parent %p\n",
                                 child, parent);
                goto out_put;
        }

        if (verbose > 0) {
                printf("fork event\n");
                printf("... parent: %s/%d\n", thread__comm_str(parent), parent->tid);
                printf("...  child: %s/%d\n", thread__comm_str(child), child->tid);
        }

        register_pid(sched, parent->tid, thread__comm_str(parent));
        register_pid(sched, child->tid, thread__comm_str(child));
out_put:
        thread__put(child);
        thread__put(parent);
        return 0;
}

struct sort_dimension {
        const char              *name;
        sort_fn_t               cmp;
        struct list_head        list;
};

/*
 * handle runtime stats saved per thread
 */
static struct thread_runtime *thread__init_runtime(struct thread *thread)
{
        struct thread_runtime *r;

        r = zalloc(sizeof(struct thread_runtime));
        if (!r)
                return NULL;

        init_stats(&r->run_stats);
        thread__set_priv(thread, r);

        return r;
}

static struct thread_runtime *thread__get_runtime(struct thread *thread)
{
        struct thread_runtime *tr;

        tr = thread__priv(thread);
        if (tr == NULL) {
                tr = thread__init_runtime(thread);
                if (tr == NULL)
                        pr_debug("Failed to malloc memory for runtime data.\n");
        }

        return tr;
}

static int
thread_lat_cmp(struct list_head *list, struct work_atoms *l, struct work_atoms *r)
{
        struct sort_dimension *sort;
        int ret = 0;

        BUG_ON(list_empty(list));

        list_for_each_entry(sort, list, list) {
                ret = sort->cmp(l, r);
                if (ret)
                        return ret;
        }

        return ret;
}

static struct work_atoms *
thread_atoms_search(struct rb_root_cached *root, struct thread *thread,
                         struct list_head *sort_list)
{
        struct rb_node *node = root->rb_root.rb_node;
        struct work_atoms key = { .thread = thread };

        while (node) {
                struct work_atoms *atoms;
                int cmp;

                atoms = container_of(node, struct work_atoms, node);

                cmp = thread_lat_cmp(sort_list, &key, atoms);
                if (cmp > 0)
                        node = node->rb_left;
                else if (cmp < 0)
                        node = node->rb_right;
                else {
                        BUG_ON(thread != atoms->thread);
                        return atoms;
                }
        }
        return NULL;
}

static void
__thread_latency_insert(struct rb_root_cached *root, struct work_atoms *data,
                         struct list_head *sort_list)
{
        struct rb_node **new = &(root->rb_root.rb_node), *parent = NULL;
        bool leftmost = true;

        while (*new) {
                struct work_atoms *this;
                int cmp;

                this = container_of(*new, struct work_atoms, node);
                parent = *new;

                cmp = thread_lat_cmp(sort_list, data, this);

                if (cmp > 0)
                        new = &((*new)->rb_left);
                else {
                        new = &((*new)->rb_right);
                        leftmost = false;
                }
        }

        rb_link_node(&data->node, parent, new);
        rb_insert_color_cached(&data->node, root, leftmost);
}

static int thread_atoms_insert(struct perf_sched *sched, struct thread *thread)
{
        struct work_atoms *atoms = zalloc(sizeof(*atoms));
        if (!atoms) {
                pr_err("No memory at %s\n", __func__);
                return -1;
        }

        atoms->thread = thread__get(thread);
        INIT_LIST_HEAD(&atoms->work_list);
        __thread_latency_insert(&sched->atom_root, atoms, &sched->cmp_pid);
        return 0;
}

static char sched_out_state(u64 prev_state)
{
        const char *str = TASK_STATE_TO_CHAR_STR;

        return str[prev_state];
}

static int
add_sched_out_event(struct work_atoms *atoms,
                    char run_state,
                    u64 timestamp)
{
        struct work_atom *atom = zalloc(sizeof(*atom));
        if (!atom) {
                pr_err("Non memory at %s", __func__);
                return -1;
        }

        atom->sched_out_time = timestamp;

        if (run_state == 'R') {
                atom->state = THREAD_WAIT_CPU;
                atom->wake_up_time = atom->sched_out_time;
        }

        list_add_tail(&atom->list, &atoms->work_list);
        return 0;
}

static void
add_runtime_event(struct work_atoms *atoms, u64 delta,
                  u64 timestamp __maybe_unused)
{
        struct work_atom *atom;

        BUG_ON(list_empty(&atoms->work_list));

        atom = list_entry(atoms->work_list.prev, struct work_atom, list);

        atom->runtime += delta;
        atoms->total_runtime += delta;
}

static void
add_sched_in_event(struct work_atoms *atoms, u64 timestamp)
{
        struct work_atom *atom;
        u64 delta;

        if (list_empty(&atoms->work_list))
                return;

        atom = list_entry(atoms->work_list.prev, struct work_atom, list);

        if (atom->state != THREAD_WAIT_CPU)
                return;

        if (timestamp < atom->wake_up_time) {
                atom->state = THREAD_IGNORE;
                return;
        }

        atom->state = THREAD_SCHED_IN;
        atom->sched_in_time = timestamp;

        delta = atom->sched_in_time - atom->wake_up_time;
        atoms->total_lat += delta;
        if (delta > atoms->max_lat) {
                atoms->max_lat = delta;
                atoms->max_lat_at = timestamp;
        }
        atoms->nb_atoms++;
}

static int latency_switch_event(struct perf_sched *sched,
                                struct evsel *evsel,
                                struct perf_sample *sample,
                                struct machine *machine)
{
        const u32 prev_pid = perf_evsel__intval(evsel, sample, "prev_pid"),
                  next_pid = perf_evsel__intval(evsel, sample, "next_pid");
        const u64 prev_state = perf_evsel__intval(evsel, sample, "prev_state");
        struct work_atoms *out_events, *in_events;
        struct thread *sched_out, *sched_in;
        u64 timestamp0, timestamp = sample->time;
        int cpu = sample->cpu, err = -1;
        s64 delta;

        BUG_ON(cpu >= MAX_CPUS || cpu < 0);

        timestamp0 = sched->cpu_last_switched[cpu];
        sched->cpu_last_switched[cpu] = timestamp;
        if (timestamp0)
                delta = timestamp - timestamp0;
        else
                delta = 0;

        if (delta < 0) {
                pr_err("hm, delta: %" PRIu64 " < 0 ?\n", delta);
                return -1;
        }

        sched_out = machine__findnew_thread(machine, -1, prev_pid);
        sched_in = machine__findnew_thread(machine, -1, next_pid);
        if (sched_out == NULL || sched_in == NULL)
                goto out_put;

        out_events = thread_atoms_search(&sched->atom_root, sched_out, &sched->cmp_pid);
        if (!out_events) {
                if (thread_atoms_insert(sched, sched_out))
                        goto out_put;
                out_events = thread_atoms_search(&sched->atom_root, sched_out, &sched->cmp_pid);
                if (!out_events) {
                        pr_err("out-event: Internal tree error");
                        goto out_put;
                }
        }
        if (add_sched_out_event(out_events, sched_out_state(prev_state), timestamp))
                return -1;

        in_events = thread_atoms_search(&sched->atom_root, sched_in, &sched->cmp_pid);
        if (!in_events) {
                if (thread_atoms_insert(sched, sched_in))
                        goto out_put;
                in_events = thread_atoms_search(&sched->atom_root, sched_in, &sched->cmp_pid);
                if (!in_events) {
                        pr_err("in-event: Internal tree error");
                        goto out_put;
                }
                /*
                 * Take came in we have not heard about yet,
                 * add in an initial atom in runnable state:
                 */
                if (add_sched_out_event(in_events, 'R', timestamp))
                        goto out_put;
        }
        add_sched_in_event(in_events, timestamp);
        err = 0;
out_put:
        thread__put(sched_out);
        thread__put(sched_in);
        return err;
}

static int latency_runtime_event(struct perf_sched *sched,
                                 struct evsel *evsel,
                                 struct perf_sample *sample,
                                 struct machine *machine)
{
        const u32 pid      = perf_evsel__intval(evsel, sample, "pid");
        const u64 runtime  = perf_evsel__intval(evsel, sample, "runtime");
        struct thread *thread = machine__findnew_thread(machine, -1, pid);
        struct work_atoms *atoms = thread_atoms_search(&sched->atom_root, thread, &sched->cmp_pid);
        u64 timestamp = sample->time;
        int cpu = sample->cpu, err = -1;

        if (thread == NULL)
                return -1;

        BUG_ON(cpu >= MAX_CPUS || cpu < 0);
        if (!atoms) {
                if (thread_atoms_insert(sched, thread))
                        goto out_put;
                atoms = thread_atoms_search(&sched->atom_root, thread, &sched->cmp_pid);
                if (!atoms) {
                        pr_err("in-event: Internal tree error");
                        goto out_put;
                }
                if (add_sched_out_event(atoms, 'R', timestamp))
                        goto out_put;
        }

        add_runtime_event(atoms, runtime, timestamp);
        err = 0;
out_put:
        thread__put(thread);
        return err;
}

static int latency_wakeup_event(struct perf_sched *sched,
                                struct evsel *evsel,
                                struct perf_sample *sample,
                                struct machine *machine)
{
        const u32 pid     = perf_evsel__intval(evsel, sample, "pid");
        struct work_atoms *atoms;
        struct work_atom *atom;
        struct thread *wakee;
        u64 timestamp = sample->time;
        int err = -1;

        wakee = machine__findnew_thread(machine, -1, pid);
        if (wakee == NULL)
                return -1;
        atoms = thread_atoms_search(&sched->atom_root, wakee, &sched->cmp_pid);
        if (!atoms) {
                if (thread_atoms_insert(sched, wakee))
                        goto out_put;
                atoms = thread_atoms_search(&sched->atom_root, wakee, &sched->cmp_pid);
                if (!atoms) {
                        pr_err("wakeup-event: Internal tree error");
                        goto out_put;
                }
                if (add_sched_out_event(atoms, 'S', timestamp))
                        goto out_put;
        }

        BUG_ON(list_empty(&atoms->work_list));

        atom = list_entry(atoms->work_list.prev, struct work_atom, list);

        /*
         * As we do not guarantee the wakeup event happens when
         * task is out of run queue, also may happen when task is
         * on run queue and wakeup only change ->state to TASK_RUNNING,
         * then we should not set the ->wake_up_time when wake up a
         * task which is on run queue.
         *
         * You WILL be missing events if you've recorded only
         * one CPU, or are only looking at only one, so don't
         * skip in this case.
         */
        if (sched->profile_cpu == -1 && atom->state != THREAD_SLEEPING)
                goto out_ok;

        sched->nr_timestamps++;
        if (atom->sched_out_time > timestamp) {
                sched->nr_unordered_timestamps++;
                goto out_ok;
        }

        atom->state = THREAD_WAIT_CPU;
        atom->wake_up_time = timestamp;
out_ok:
        err = 0;
out_put:
        thread__put(wakee);
        return err;
}

static int latency_migrate_task_event(struct perf_sched *sched,
                                      struct evsel *evsel,
                                      struct perf_sample *sample,
                                      struct machine *machine)
{
        const u32 pid = perf_evsel__intval(evsel, sample, "pid");
        u64 timestamp = sample->time;
        struct work_atoms *atoms;
        struct work_atom *atom;
        struct thread *migrant;
        int err = -1;

        /*
         * Only need to worry about migration when profiling one CPU.
         */
        if (sched->profile_cpu == -1)
                return 0;

        migrant = machine__findnew_thread(machine, -1, pid);
        if (migrant == NULL)
                return -1;
        atoms = thread_atoms_search(&sched->atom_root, migrant, &sched->cmp_pid);
        if (!atoms) {
                if (thread_atoms_insert(sched, migrant))
                        goto out_put;
                register_pid(sched, migrant->tid, thread__comm_str(migrant));
                atoms = thread_atoms_search(&sched->atom_root, migrant, &sched->cmp_pid);
                if (!atoms) {
                        pr_err("migration-event: Internal tree error");
                        goto out_put;
                }
                if (add_sched_out_event(atoms, 'R', timestamp))
                        goto out_put;
        }

        BUG_ON(list_empty(&atoms->work_list));

        atom = list_entry(atoms->work_list.prev, struct work_atom, list);
        atom->sched_in_time = atom->sched_out_time = atom->wake_up_time = timestamp;

        sched->nr_timestamps++;

        if (atom->sched_out_time > timestamp)
                sched->nr_unordered_timestamps++;
        err = 0;
out_put:
        thread__put(migrant);
        return err;
}

static void output_lat_thread(struct perf_sched *sched, struct work_atoms *work_list)
{
        int i;
        int ret;
        u64 avg;
        char max_lat_at[32];

        if (!work_list->nb_atoms)
                return;
        /*
         * Ignore idle threads:
         */
        if (!strcmp(thread__comm_str(work_list->thread), "swapper"))
                return;

        sched->all_runtime += work_list->total_runtime;
        sched->all_count   += work_list->nb_atoms;

        if (work_list->num_merged > 1)
                ret = printf("  %s:(%d) ", thread__comm_str(work_list->thread), work_list->num_merged);
        else
                ret = printf("  %s:%d ", thread__comm_str(work_list->thread), work_list->thread->tid);

        for (i = 0; i < 24 - ret; i++)
                printf(" ");

        avg = work_list->total_lat / work_list->nb_atoms;
        timestamp__scnprintf_usec(work_list->max_lat_at, max_lat_at, sizeof(max_lat_at));

        printf("|%11.3f ms |%9" PRIu64 " | avg:%9.3f ms | max:%9.3f ms | max at: %13s s\n",
              (double)work_list->total_runtime / NSEC_PER_MSEC,
                 work_list->nb_atoms, (double)avg / NSEC_PER_MSEC,
                 (double)work_list->max_lat / NSEC_PER_MSEC,
                 max_lat_at);
}

static int pid_cmp(struct work_atoms *l, struct work_atoms *r)
{
        if (l->thread == r->thread)
                return 0;
        if (l->thread->tid < r->thread->tid)
                return -1;
        if (l->thread->tid > r->thread->tid)
                return 1;
        return (int)(l->thread - r->thread);
}

static int avg_cmp(struct work_atoms *l, struct work_atoms *r)
{
        u64 avgl, avgr;

        if (!l->nb_atoms)
                return -1;

        if (!r->nb_atoms)
                return 1;

        avgl = l->total_lat / l->nb_atoms;
        avgr = r->total_lat / r->nb_atoms;

        if (avgl < avgr)
                return -1;
        if (avgl > avgr)
                return 1;

        return 0;
}

static int max_cmp(struct work_atoms *l, struct work_atoms *r)
{
        if (l->max_lat < r->max_lat)
                return -1;
        if (l->max_lat > r->max_lat)
                return 1;

        return 0;
}

static int switch_cmp(struct work_atoms *l, struct work_atoms *r)
{
        if (l->nb_atoms < r->nb_atoms)
                return -1;
        if (l->nb_atoms > r->nb_atoms)
                return 1;

        return 0;
}

static int runtime_cmp(struct work_atoms *l, struct work_atoms *r)
{
        if (l->total_runtime < r->total_runtime)
                return -1;
        if (l->total_runtime > r->total_runtime)
                return 1;

        return 0;
}

static int sort_dimension__add(const char *tok, struct list_head *list)
{
        size_t i;
        static struct sort_dimension avg_sort_dimension = {
                .name = "avg",
                .cmp  = avg_cmp,
        };
        static struct sort_dimension max_sort_dimension = {
                .name = "max",
                .cmp  = max_cmp,
        };
        static struct sort_dimension pid_sort_dimension = {
                .name = "pid",
                .cmp  = pid_cmp,
        };
        static struct sort_dimension runtime_sort_dimension = {
                .name = "runtime",
                .cmp  = runtime_cmp,
        };
        static struct sort_dimension switch_sort_dimension = {
                .name = "switch",
                .cmp  = switch_cmp,
        };
        struct sort_dimension *available_sorts[] = {
                &pid_sort_dimension,
                &avg_sort_dimension,
                &max_sort_dimension,
                &switch_sort_dimension,
                &runtime_sort_dimension,
        };

        for (i = 0; i < ARRAY_SIZE(available_sorts); i++) {
                if (!strcmp(available_sorts[i]->name, tok)) {
                        list_add_tail(&available_sorts[i]->list, list);

                        return 0;
                }
        }

        return -1;
}

static void perf_sched__sort_lat(struct perf_sched *sched)
{
        struct rb_node *node;
        struct rb_root_cached *root = &sched->atom_root;
again:
        for (;;) {
                struct work_atoms *data;
                node = rb_first_cached(root);
                if (!node)
                        break;

                rb_erase_cached(node, root);
                data = rb_entry(node, struct work_atoms, node);
                __thread_latency_insert(&sched->sorted_atom_root, data, &sched->sort_list);
        }
        if (root == &sched->atom_root) {
                root = &sched->merged_atom_root;
                goto again;
        }
}

static int process_sched_wakeup_event(struct perf_tool *tool,
                                      struct evsel *evsel,
                                      struct perf_sample *sample,
                                      struct machine *machine)
{
        struct perf_sched *sched = container_of(tool, struct perf_sched, tool);

        if (sched->tp_handler->wakeup_event)
                return sched->tp_handler->wakeup_event(sched, evsel, sample, machine);

        return 0;
}

union map_priv {
        void    *ptr;
        bool     color;
};

static bool thread__has_color(struct thread *thread)
{
        union map_priv priv = {
                .ptr = thread__priv(thread),
        };

        return priv.color;
}

static struct thread*
map__findnew_thread(struct perf_sched *sched, struct machine *machine, pid_t pid, pid_t tid)
{
        struct thread *thread = machine__findnew_thread(machine, pid, tid);
        union map_priv priv = {
                .color = false,
        };

        if (!sched->map.color_pids || !thread || thread__priv(thread))
                return thread;

        if (thread_map__has(sched->map.color_pids, tid))
                priv.color = true;

        thread__set_priv(thread, priv.ptr);
        return thread;
}

static int map_switch_event(struct perf_sched *sched, struct evsel *evsel,
                            struct perf_sample *sample, struct machine *machine)
{
        const u32 next_pid = perf_evsel__intval(evsel, sample, "next_pid");
        struct thread *sched_in;
        struct thread_runtime *tr;
        int new_shortname;
        u64 timestamp0, timestamp = sample->time;
        s64 delta;
        int i, this_cpu = sample->cpu;
        int cpus_nr;
        bool new_cpu = false;
        const char *color = PERF_COLOR_NORMAL;
        char stimestamp[32];

        BUG_ON(this_cpu >= MAX_CPUS || this_cpu < 0);

        if (this_cpu > sched->max_cpu)
                sched->max_cpu = this_cpu;

        if (sched->map.comp) {
                cpus_nr = bitmap_weight(sched->map.comp_cpus_mask, MAX_CPUS);
                if (!test_and_set_bit(this_cpu, sched->map.comp_cpus_mask)) {
                        sched->map.comp_cpus[cpus_nr++] = this_cpu;
                        new_cpu = true;
                }
        } else
                cpus_nr = sched->max_cpu;

        timestamp0 = sched->cpu_last_switched[this_cpu];
        sched->cpu_last_switched[this_cpu] = timestamp;
        if (timestamp0)
                delta = timestamp - timestamp0;
        else
                delta = 0;

        if (delta < 0) {
                pr_err("hm, delta: %" PRIu64 " < 0 ?\n", delta);
                return -1;
        }

        sched_in = map__findnew_thread(sched, machine, -1, next_pid);
        if (sched_in == NULL)
                return -1;

        tr = thread__get_runtime(sched_in);
        if (tr == NULL) {
                thread__put(sched_in);
                return -1;
        }

        sched->curr_thread[this_cpu] = thread__get(sched_in);

        printf("  ");

        new_shortname = 0;
        if (!tr->shortname[0]) {
                if (!strcmp(thread__comm_str(sched_in), "swapper")) {
                        /*
                         * Don't allocate a letter-number for swapper:0
                         * as a shortname. Instead, we use '.' for it.
                         */
                        tr->shortname[0] = '.';
                        tr->shortname[1] = ' ';
                } else {
                        tr->shortname[0] = sched->next_shortname1;
                        tr->shortname[1] = sched->next_shortname2;

                        if (sched->next_shortname1 < 'Z') {
                                sched->next_shortname1++;
                        } else {
                                sched->next_shortname1 = 'A';
                                if (sched->next_shortname2 < '9')
                                        sched->next_shortname2++;
                                else
                                        sched->next_shortname2 = '0';
                        }
                }
                new_shortname = 1;
        }

        for (i = 0; i < cpus_nr; i++) {
                int cpu = sched->map.comp ? sched->map.comp_cpus[i] : i;
                struct thread *curr_thread = sched->curr_thread[cpu];
                struct thread_runtime *curr_tr;
                const char *pid_color = color;
                const char *cpu_color = color;

                if (curr_thread && thread__has_color(curr_thread))
                        pid_color = COLOR_PIDS;

                if (sched->map.cpus && !cpu_map__has(sched->map.cpus, cpu))
                        continue;

                if (sched->map.color_cpus && cpu_map__has(sched->map.color_cpus, cpu))
                        cpu_color = COLOR_CPUS;

                if (cpu != this_cpu)
                        color_fprintf(stdout, color, " ");
                else
                        color_fprintf(stdout, cpu_color, "*");

                if (sched->curr_thread[cpu]) {
                        curr_tr = thread__get_runtime(sched->curr_thread[cpu]);
                        if (curr_tr == NULL) {
                                thread__put(sched_in);
                                return -1;
                        }
                        color_fprintf(stdout, pid_color, "%2s ", curr_tr->shortname);
                } else
                        color_fprintf(stdout, color, "   ");
        }

        if (sched->map.cpus && !cpu_map__has(sched->map.cpus, this_cpu))
                goto out;

        timestamp__scnprintf_usec(timestamp, stimestamp, sizeof(stimestamp));
        color_fprintf(stdout, color, "  %12s secs ", stimestamp);
        if (new_shortname || tr->comm_changed || (verbose > 0 && sched_in->tid)) {
                const char *pid_color = color;

                if (thread__has_color(sched_in))
                        pid_color = COLOR_PIDS;

                color_fprintf(stdout, pid_color, "%s => %s:%d",
                       tr->shortname, thread__comm_str(sched_in), sched_in->tid);
                tr->comm_changed = false;
        }

        if (sched->map.comp && new_cpu)
                color_fprintf(stdout, color, " (CPU %d)", this_cpu);

out:
        color_fprintf(stdout, color, "\n");

        thread__put(sched_in);

        return 0;
}

static int process_sched_switch_event(struct perf_tool *tool,
                                      struct evsel *evsel,
                                      struct perf_sample *sample,
                                      struct machine *machine)
{
        struct perf_sched *sched = container_of(tool, struct perf_sched, tool);
        int this_cpu = sample->cpu, err = 0;
        u32 prev_pid = perf_evsel__intval(evsel, sample, "prev_pid"),
            next_pid = perf_evsel__intval(evsel, sample, "next_pid");

        if (sched->curr_pid[this_cpu] != (u32)-1) {
                /*
                 * Are we trying to switch away a PID that is
                 * not current?
                 */
                if (sched->curr_pid[this_cpu] != prev_pid)
                        sched->nr_context_switch_bugs++;
        }

        if (sched->tp_handler->switch_event)
                err = sched->tp_handler->switch_event(sched, evsel, sample, machine);

        sched->curr_pid[this_cpu] = next_pid;
        return err;
}

static int process_sched_runtime_event(struct perf_tool *tool,
                                       struct evsel *evsel,
                                       struct perf_sample *sample,
                                       struct machine *machine)
{
        struct perf_sched *sched = container_of(tool, struct perf_sched, tool);

        if (sched->tp_handler->runtime_event)
                return sched->tp_handler->runtime_event(sched, evsel, sample, machine);

        return 0;
}

static int perf_sched__process_fork_event(struct perf_tool *tool,
                                          union perf_event *event,
                                          struct perf_sample *sample,
                                          struct machine *machine)
{
        struct perf_sched *sched = container_of(tool, struct perf_sched, tool);

        /* run the fork event through the perf machineruy */
        perf_event__process_fork(tool, event, sample, machine);

        /* and then run additional processing needed for this command */
        if (sched->tp_handler->fork_event)
                return sched->tp_handler->fork_event(sched, event, machine);

        return 0;
}

static int process_sched_migrate_task_event(struct perf_tool *tool,
                                            struct evsel *evsel,
                                            struct perf_sample *sample,
                                            struct machine *machine)
{
        struct perf_sched *sched = container_of(tool, struct perf_sched, tool);

        if (sched->tp_handler->migrate_task_event)
                return sched->tp_handler->migrate_task_event(sched, evsel, sample, machine);

        return 0;
}

typedef int (*tracepoint_handler)(struct perf_tool *tool,
                                  struct evsel *evsel,
                                  struct perf_sample *sample,
                                  struct machine *machine);

static int perf_sched__process_tracepoint_sample(struct perf_tool *tool __maybe_unused,
                                                 union perf_event *event __maybe_unused,
                                                 struct perf_sample *sample,
                                                 struct evsel *evsel,
                                                 struct machine *machine)
{
        int err = 0;

        if (evsel->handler != NULL) {
                tracepoint_handler f = evsel->handler;
                err = f(tool, evsel, sample, machine);
        }

        return err;
}

static int perf_sched__process_comm(struct perf_tool *tool __maybe_unused,
                                    union perf_event *event,
                                    struct perf_sample *sample,
                                    struct machine *machine)
{
        struct thread *thread;
        struct thread_runtime *tr;
        int err;

        err = perf_event__process_comm(tool, event, sample, machine);
        if (err)
                return err;

        thread = machine__find_thread(machine, sample->pid, sample->tid);
        if (!thread) {
                pr_err("Internal error: can't find thread\n");
                return -1;
        }

        tr = thread__get_runtime(thread);
        if (tr == NULL) {
                thread__put(thread);
                return -1;
        }

        tr->comm_changed = true;
        thread__put(thread);

        return 0;
}

static int perf_sched__read_events(struct perf_sched *sched)
{
        const struct evsel_str_handler handlers[] = {
                { "sched:sched_switch",       process_sched_switch_event, },
                { "sched:sched_stat_runtime", process_sched_runtime_event, },
                { "sched:sched_wakeup",       process_sched_wakeup_event, },
                { "sched:sched_wakeup_new",   process_sched_wakeup_event, },
                { "sched:sched_migrate_task", process_sched_migrate_task_event, },
        };
        struct perf_session *session;
        struct perf_data data = {
                .path  = input_name,
                .mode  = PERF_DATA_MODE_READ,
                .force = sched->force,
        };
        int rc = -1;

        session = perf_session__new(&data, false, &sched->tool);
        if (IS_ERR(session)) {
                pr_debug("Error creating perf session");
                return PTR_ERR(session);
        }

        symbol__init(&session->header.env);

        if (perf_session__set_tracepoints_handlers(session, handlers))
                goto out_delete;

        if (perf_session__has_traces(session, "record -R")) {
                int err = perf_session__process_events(session);
                if (err) {
                        pr_err("Failed to process events, error %d", err);
                        goto out_delete;
                }

                sched->nr_events      = session->evlist->stats.nr_events[0];
                sched->nr_lost_events = session->evlist->stats.total_lost;
                sched->nr_lost_chunks = session->evlist->stats.nr_events[PERF_RECORD_LOST];
        }

        rc = 0;
out_delete:
        perf_session__delete(session);
        return rc;
}

/*
 * scheduling times are printed as msec.usec
 */
static inline void print_sched_time(unsigned long long nsecs, int width)
{
        unsigned long msecs;
        unsigned long usecs;

        msecs  = nsecs / NSEC_PER_MSEC;
        nsecs -= msecs * NSEC_PER_MSEC;
        usecs  = nsecs / NSEC_PER_USEC;
        printf("%*lu.%03lu ", width, msecs, usecs);
}

/*
 * returns runtime data for event, allocating memory for it the
 * first time it is used.
 */
static struct evsel_runtime *perf_evsel__get_runtime(struct evsel *evsel)
{
        struct evsel_runtime *r = evsel->priv;

        if (r == NULL) {
                r = zalloc(sizeof(struct evsel_runtime));
                evsel->priv = r;
        }

        return r;
}

/*
 * save last time event was seen per cpu
 */
static void perf_evsel__save_time(struct evsel *evsel,
                                  u64 timestamp, u32 cpu)
{
        struct evsel_runtime *r = perf_evsel__get_runtime(evsel);

        if (r == NULL)
                return;

        if ((cpu >= r->ncpu) || (r->last_time == NULL)) {
                int i, n = __roundup_pow_of_two(cpu+1);
                void *p = r->last_time;

                p = realloc(r->last_time, n * sizeof(u64));
                if (!p)
                        return;

                r->last_time = p;
                for (i = r->ncpu; i < n; ++i)
                        r->last_time[i] = (u64) 0;

                r->ncpu = n;
        }

        r->last_time[cpu] = timestamp;
}

/* returns last time this event was seen on the given cpu */
static u64 perf_evsel__get_time(struct evsel *evsel, u32 cpu)
{
        struct evsel_runtime *r = perf_evsel__get_runtime(evsel);

        if ((r == NULL) || (r->last_time == NULL) || (cpu >= r->ncpu))
                return 0;

        return r->last_time[cpu];
}

static int comm_width = 30;

static char *timehist_get_commstr(struct thread *thread)
{
        static char str[32];
        const char *comm = thread__comm_str(thread);
        pid_t tid = thread->tid;
        pid_t pid = thread->pid_;
        int n;

        if (pid == 0)
                n = scnprintf(str, sizeof(str), "%s", comm);

        else if (tid != pid)
                n = scnprintf(str, sizeof(str), "%s[%d/%d]", comm, tid, pid);

        else
                n = scnprintf(str, sizeof(str), "%s[%d]", comm, tid);

        if (n > comm_width)
                comm_width = n;

        return str;
}

static void timehist_header(struct perf_sched *sched)
{
        u32 ncpus = sched->max_cpu + 1;
        u32 i, j;

        printf("%15s %6s ", "time", "cpu");

        if (sched->show_cpu_visual) {
                printf(" ");
                for (i = 0, j = 0; i < ncpus; ++i) {
                        printf("%x", j++);
                        if (j > 15)
                                j = 0;
                }
                printf(" ");
        }

        printf(" %-*s  %9s  %9s  %9s", comm_width,
                "task name", "wait time", "sch delay", "run time");

        if (sched->show_state)
                printf("  %s", "state");

        printf("\n");

        /*
         * units row
         */
        printf("%15s %-6s ", "", "");

        if (sched->show_cpu_visual)
                printf(" %*s ", ncpus, "");

        printf(" %-*s  %9s  %9s  %9s", comm_width,
               "[tid/pid]", "(msec)", "(msec)", "(msec)");

        if (sched->show_state)
                printf("  %5s", "");

        printf("\n");

        /*
         * separator
         */
        printf("%.15s %.6s ", graph_dotted_line, graph_dotted_line);

        if (sched->show_cpu_visual)
                printf(" %.*s ", ncpus, graph_dotted_line);

        printf(" %.*s  %.9s  %.9s  %.9s", comm_width,
                graph_dotted_line, graph_dotted_line, graph_dotted_line,
                graph_dotted_line);

        if (sched->show_state)
                printf("  %.5s", graph_dotted_line);

        printf("\n");
}

static char task_state_char(struct thread *thread, int state)
{
        static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
        unsigned bit = state ? ffs(state) : 0;

        /* 'I' for idle */
        if (thread->tid == 0)
                return 'I';

        return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
}

static void timehist_print_sample(struct perf_sched *sched,
                                  struct evsel *evsel,
                                  struct perf_sample *sample,
                                  struct addr_location *al,
                                  struct thread *thread,

                                  u64 t, int state)
{
        struct thread_runtime *tr = thread__priv(thread);
        const char *next_comm = perf_evsel__strval(evsel, sample, "next_comm");
        const u32 next_pid = perf_evsel__intval(evsel, sample, "next_pid");
        u32 max_cpus = sched->max_cpu + 1;
        char tstr[64];
        char nstr[30];
        u64 wait_time;

        timestamp__scnprintf_usec(t, tstr, sizeof(tstr));
        printf("%15s [%04d] ", tstr, sample->cpu);

        if (sched->show_cpu_visual) {
                u32 i;
                char c;

                printf(" ");
                for (i = 0; i < max_cpus; ++i) {
                        /* flag idle times with 'i'; others are sched events */
                        if (i == sample->cpu)
                                c = (thread->tid == 0) ? 'i' : 's';
                        else
                                c = ' ';
                        printf("%c", c);
                }
                printf(" ");
        }

        printf(" %-*s ", comm_width, timehist_get_commstr(thread));

        wait_time = tr->dt_sleep + tr->dt_iowait + tr->dt_preempt;
        print_sched_time(wait_time, 6);

        print_sched_time(tr->dt_delay, 6);
        print_sched_time(tr->dt_run, 6);

        if (sched->show_state)
                printf(" %5c ", task_state_char(thread, state));

        if (sched->show_next) {
                snprintf(nstr, sizeof(nstr), "next: %s[%d]", next_comm, next_pid);
                printf(" %-*s", comm_width, nstr);
        }

        if (sched->show_wakeups && !sched->show_next)
                printf("  %-*s", comm_width, "");

        if (thread->tid == 0)
                goto out;

        if (sched->show_callchain)
                printf("  ");

        sample__fprintf_sym(sample, al, 0,
                            EVSEL__PRINT_SYM | EVSEL__PRINT_ONELINE |
                            EVSEL__PRINT_CALLCHAIN_ARROW |
                            EVSEL__PRINT_SKIP_IGNORED,
                            &callchain_cursor, symbol_conf.bt_stop_list,  stdout);

out:
        printf("\n");
}

/*
 * Explanation of delta-time stats:
 *
 *            t = time of current schedule out event
 *        tprev = time of previous sched out event
 *                also time of schedule-in event for current task
 *    last_time = time of last sched change event for current task
 *                (i.e, time process was last scheduled out)
 * ready_to_run = time of wakeup for current task
 *
 * -----|------------|------------|------------|------
 *    last         ready        tprev          t
 *    time         to run
 *
 *      |-------- dt_wait --------|
 *                   |- dt_delay -|-- dt_run --|
 *
 *   dt_run = run time of current task
 *  dt_wait = time between last schedule out event for task and tprev
 *            represents time spent off the cpu
 * dt_delay = time between wakeup and schedule-in of task
 */

static void timehist_update_runtime_stats(struct thread_runtime *r,
                                         u64 t, u64 tprev)
{
        r->dt_delay   = 0;
        r->dt_sleep   = 0;
        r->dt_iowait  = 0;
        r->dt_preempt = 0;
        r->dt_run     = 0;

        if (tprev) {
                r->dt_run = t - tprev;
                if (r->ready_to_run) {
                        if (r->ready_to_run > tprev)
                                pr_debug("time travel: wakeup time for task > previous sched_switch event\n");
                        else
                                r->dt_delay = tprev - r->ready_to_run;
                }

                if (r->last_time > tprev)
                        pr_debug("time travel: last sched out time for task > previous sched_switch event\n");
                else if (r->last_time) {
                        u64 dt_wait = tprev - r->last_time;

                        if (r->last_state == TASK_RUNNING)
                                r->dt_preempt = dt_wait;
                        else if (r->last_state == TASK_UNINTERRUPTIBLE)
                                r->dt_iowait = dt_wait;
                        else
                                r->dt_sleep = dt_wait;
                }
        }

        update_stats(&r->run_stats, r->dt_run);

        r->total_run_time     += r->dt_run;
        r->total_delay_time   += r->dt_delay;
        r->total_sleep_time   += r->dt_sleep;
        r->total_iowait_time  += r->dt_iowait;
        r->total_preempt_time += r->dt_preempt;
}

static bool is_idle_sample(struct perf_sample *sample,
                           struct evsel *evsel)
{
        /* pid 0 == swapper == idle task */
        if (strcmp(perf_evsel__name(evsel), "sched:sched_switch") == 0)
                return perf_evsel__intval(evsel, sample, "prev_pid") == 0;

        return sample->pid == 0;
}

static void save_task_callchain(struct perf_sched *sched,
                                struct perf_sample *sample,
                                struct evsel *evsel,
                                struct machine *machine)
{
        struct callchain_cursor *cursor = &callchain_cursor;
        struct thread *thread;

        /* want main thread for process - has maps */
        thread = machine__findnew_thread(machine, sample->pid, sample->pid);
        if (thread == NULL) {
                pr_debug("Failed to get thread for pid %d.\n", sample->pid);
                return;
        }

        if (!sched->show_callchain || sample->callchain == NULL)
                return;

        if (thread__resolve_callchain(thread, cursor, evsel, sample,
                                      NULL, NULL, sched->max_stack + 2) != 0) {
                if (verbose > 0)
                        pr_err("Failed to resolve callchain. Skipping\n");

                return;
        }

        callchain_cursor_commit(cursor);

        while (true) {
                struct callchain_cursor_node *node;
                struct symbol *sym;

                node = callchain_cursor_current(cursor);
                if (node == NULL)
                        break;

                sym = node->sym;
                if (sym) {
                        if (!strcmp(sym->name, "schedule") ||
                            !strcmp(sym->name, "__schedule") ||
                            !strcmp(sym->name, "preempt_schedule"))
                                sym->ignore = 1;
                }

                callchain_cursor_advance(cursor);
        }
}

static int init_idle_thread(struct thread *thread)
{
        struct idle_thread_runtime *itr;

        thread__set_comm(thread, idle_comm, 0);

        itr = zalloc(sizeof(*itr));
        if (itr == NULL)
                return -ENOMEM;

        init_stats(&itr->tr.run_stats);
        callchain_init(&itr->callchain);
        callchain_cursor_reset(&itr->cursor);
        thread__set_priv(thread, itr);

        return 0;
}

/*
 * Track idle stats per cpu by maintaining a local thread
 * struct for the idle task on each cpu.
 */
static int init_idle_threads(int ncpu)
{
        int i, ret;

        idle_threads = zalloc(ncpu * sizeof(struct thread *));
        if (!idle_threads)
                return -ENOMEM;

        idle_max_cpu = ncpu;

        /* allocate the actual thread struct if needed */
        for (i = 0; i < ncpu; ++i) {
                idle_threads[i] = thread__new(0, 0);
                if (idle_threads[i] == NULL)
                        return -ENOMEM;

                ret = init_idle_thread(idle_threads[i]);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static void free_idle_threads(void)
{
        int i;

        if (idle_threads == NULL)
                return;

        for (i = 0; i < idle_max_cpu; ++i) {
                if ((idle_threads[i]))
                        thread__delete(idle_threads[i]);
        }

        free(idle_threads);
}

static struct thread *get_idle_thread(int cpu)
{
        /*
         * expand/allocate array of pointers to local thread
         * structs if needed
         */
        if ((cpu >= idle_max_cpu) || (idle_threads == NULL)) {
                int i, j = __roundup_pow_of_two(cpu+1);
                void *p;

                p = realloc(idle_threads, j * sizeof(struct thread *));
                if (!p)
                        return NULL;

                idle_threads = (struct thread **) p;
                for (i = idle_max_cpu; i < j; ++i)
                        idle_threads[i] = NULL;

                idle_max_cpu = j;
        }

        /* allocate a new thread struct if needed */
        if (idle_threads[cpu] == NULL) {
                idle_threads[cpu] = thread__new(0, 0);

                if (idle_threads[cpu]) {
                        if (init_idle_thread(idle_threads[cpu]) < 0)
                                return NULL;
                }
        }

        return idle_threads[cpu];
}

static void save_idle_callchain(struct perf_sched *sched,
                                struct idle_thread_runtime *itr,
                                struct perf_sample *sample)
{
        if (!sched->show_callchain || sample->callchain == NULL)
                return;

        callchain_cursor__copy(&itr->cursor, &callchain_cursor);
}

static struct thread *timehist_get_thread(struct perf_sched *sched,
                                          struct perf_sample *sample,
                                          struct machine *machine,
                                          struct evsel *evsel)
{
        struct thread *thread;

        if (is_idle_sample(sample, evsel)) {
                thread = get_idle_thread(sample->cpu);
                if (thread == NULL)
                        pr_err("Failed to get idle thread for cpu %d.\n", sample->cpu);

        } else {
                /* there were samples with tid 0 but non-zero pid */
                thread = machine__findnew_thread(machine, sample->pid,
                                                 sample->tid ?: sample->pid);
                if (thread == NULL) {
                        pr_debug("Failed to get thread for tid %d. skipping sample.\n",
                                 sample->tid);
                }

                save_task_callchain(sched, sample, evsel, machine);
                if (sched->idle_hist) {
                        struct thread *idle;
                        struct idle_thread_runtime *itr;

                        idle = get_idle_thread(sample->cpu);
                        if (idle == NULL) {
                                pr_err("Failed to get idle thread for cpu %d.\n", sample->cpu);
                                return NULL;
                        }

                        itr = thread__priv(idle);
                        if (itr == NULL)
                                return NULL;

                        itr->last_thread = thread;

                        /* copy task callchain when entering to idle */
                        if (perf_evsel__intval(evsel, sample, "next_pid") == 0)
                                save_idle_callchain(sched, itr, sample);
                }
        }

        return thread;
}

static bool timehist_skip_sample(struct perf_sched *sched,
                                 struct thread *thread,
                                 struct evsel *evsel,
                                 struct perf_sample *sample)
{
        bool rc = false;

        if (thread__is_filtered(thread)) {
                rc = true;
                sched->skipped_samples++;
        }

        if (sched->idle_hist) {
                if (strcmp(perf_evsel__name(evsel), "sched:sched_switch"))
                        rc = true;
                else if (perf_evsel__intval(evsel, sample, "prev_pid") != 0 &&
                         perf_evsel__intval(evsel, sample, "next_pid") != 0)
                        rc = true;
        }

        return rc;
}

static void timehist_print_wakeup_event(struct perf_sched *sched,
                                        struct evsel *evsel,
                                        struct perf_sample *sample,
                                        struct machine *machine,
                                        struct thread *awakened)
{
        struct thread *thread;
        char tstr[64];

        thread = machine__findnew_thread(machine, sample->pid, sample->tid);
        if (thread == NULL)
                return;

        /* show wakeup unless both awakee and awaker are filtered */
        if (timehist_skip_sample(sched, thread, evsel, sample) &&
            timehist_skip_sample(sched, awakened, evsel, sample)) {
                return;
        }

        timestamp__scnprintf_usec(sample->time, tstr, sizeof(tstr));
        printf("%15s [%04d] ", tstr, sample->cpu);
        if (sched->show_cpu_visual)
                printf(" %*s ", sched->max_cpu + 1, "");

        printf(" %-*s ", comm_width, timehist_get_commstr(thread));

        /* dt spacer */
        printf("  %9s  %9s  %9s ", "", "", "");

        printf("awakened: %s", timehist_get_commstr(awakened));

        printf("\n");
}

static int timehist_sched_wakeup_event(struct perf_tool *tool,
                                       union perf_event *event __maybe_unused,
                                       struct evsel *evsel,
                                       struct perf_sample *sample,
                                       struct machine *machine)
{
        struct perf_sched *sched = container_of(tool, struct perf_sched, tool);
        struct thread *thread;
        struct thread_runtime *tr = NULL;
        /* want pid of awakened task not pid in sample */
        const u32 pid = perf_evsel__intval(evsel, sample, "pid");

        thread = machine__findnew_thread(machine, 0, pid);
        if (thread == NULL)
                return -1;

        tr = thread__get_runtime(thread);
        if (tr == NULL)
                return -1;

        if (tr->ready_to_run == 0)
                tr->ready_to_run = sample->time;

        /* show wakeups if requested */
        if (sched->show_wakeups &&
            !perf_time__skip_sample(&sched->ptime, sample->time))
                timehist_print_wakeup_event(sched, evsel, sample, machine, thread);

        return 0;
}

static void timehist_print_migration_event(struct perf_sched *sched,
                                        struct evsel *evsel,
                                        struct perf_sample *sample,
                                        struct machine *machine,
                                        struct thread *migrated)
{
        struct thread *thread;
        char tstr[64];
        u32 max_cpus = sched->max_cpu + 1;
        u32 ocpu, dcpu;

        if (sched->summary_only)
                return;

        max_cpus = sched->max_cpu + 1;
        ocpu = perf_evsel__intval(evsel, sample, "orig_cpu");
        dcpu = perf_evsel__intval(evsel, sample, "dest_cpu");

        thread = machine__findnew_thread(machine, sample->pid, sample->tid);
        if (thread == NULL)
                return;

        if (timehist_skip_sample(sched, thread, evsel, sample) &&
            timehist_skip_sample(sched, migrated, evsel, sample)) {
                return;
        }

        timestamp__scnprintf_usec(sample->time, tstr, sizeof(tstr));
        printf("%15s [%04d] ", tstr, sample->cpu);

        if (sched->show_cpu_visual) {
                u32 i;
                char c;

                printf("  ");
                for (i = 0; i < max_cpus; ++i) {
                        c = (i == sample->cpu) ? 'm' : ' ';
                        printf("%c", c);
                }
                printf("  ");
        }

        printf(" %-*s ", comm_width, timehist_get_commstr(thread));

        /* dt spacer */
        printf("  %9s  %9s  %9s ", "", "", "");

        printf("migrated: %s", timehist_get_commstr(migrated));
        printf(" cpu %d => %d", ocpu, dcpu);

        printf("\n");
}

static int timehist_migrate_task_event(struct perf_tool *tool,
                                       union perf_event *event __maybe_unused,
                                       struct evsel *evsel,
                                       struct perf_sample *sample,
                                       struct machine *machine)
{
        struct perf_sched *sched = container_of(tool, struct perf_sched, tool);
        struct thread *thread;
        struct thread_runtime *tr = NULL;
        /* want pid of migrated task not pid in sample */
        const u32 pid = perf_evsel__intval(evsel, sample, "pid");

        thread = machine__findnew_thread(machine, 0, pid);
        if (thread == NULL)
                return -1;

        tr = thread__get_runtime(thread);
        if (tr == NULL)
                return -1;

        tr->migrations++;

        /* show migrations if requested */
        timehist_print_migration_event(sched, evsel, sample, machine, thread);

        return 0;
}

static int timehist_sched_change_event(struct perf_tool *tool,
                                       union perf_event *event,
                                       struct evsel *evsel,
                                       struct perf_sample *sample,
                                       struct machine *machine)
{
        struct perf_sched *sched = container_of(tool, struct perf_sched, tool);
        struct perf_time_interval *ptime = &sched->ptime;
        struct addr_location al;
        struct thread *thread;
        struct thread_runtime *tr = NULL;
        u64 tprev, t = sample->time;
        int rc = 0;
        int state = perf_evsel__intval(evsel, sample, "prev_state");


        if (machine__resolve(machine, &al, sample) < 0) {
                pr_err("problem processing %d event. skipping it\n",
                       event->header.type);
                rc = -1;
                goto out;
        }

        thread = timehist_get_thread(sched, sample, machine, evsel);
        if (thread == NULL) {
                rc = -1;
                goto out;
        }

        if (timehist_skip_sample(sched, thread, evsel, sample))
                goto out;

        tr = thread__get_runtime(thread);
        if (tr == NULL) {
                rc = -1;
                goto out;
        }

        tprev = perf_evsel__get_time(evsel, sample->cpu);

        /*
         * If start time given:
         * - sample time is under window user cares about - skip sample
         * - tprev is under window user cares about  - reset to start of window
         */
        if (ptime->start && ptime->start > t)
                goto out;

        if (tprev && ptime->start > tprev)
                tprev = ptime->start;

        /*
         * If end time given:
         * - previous sched event is out of window - we are done
         * - sample time is beyond window user cares about - reset it
         *   to close out stats for time window interest
         */
        if (ptime->end) {
                if (tprev > ptime->end)
                        goto out;

                if (t > ptime->end)
                        t = ptime->end;
        }

        if (!sched->idle_hist || thread->tid == 0) {
                timehist_update_runtime_stats(tr, t, tprev);

                if (sched->idle_hist) {
                        struct idle_thread_runtime *itr = (void *)tr;
                        struct thread_runtime *last_tr;

                        BUG_ON(thread->tid != 0);

                        if (itr->last_thread == NULL)
                                goto out;

                        /* add current idle time as last thread's runtime */
                        last_tr = thread__get_runtime(itr->last_thread);
                        if (last_tr == NULL)
                                goto out;

                        timehist_update_runtime_stats(last_tr, t, tprev);
                        /*
                         * remove delta time of last thread as it's not updated
                         * and otherwise it will show an invalid value next
                         * time.  we only care total run time and run stat.
                         */
                        last_tr->dt_run = 0;
                        last_tr->dt_delay = 0;
                        last_tr->dt_sleep = 0;
                        last_tr->dt_iowait = 0;
                        last_tr->dt_preempt = 0;

                        if (itr->cursor.nr)
                                callchain_append(&itr->callchain, &itr->cursor, t - tprev);

                        itr->last_thread = NULL;
                }
        }

        if (!sched->summary_only)
                timehist_print_sample(sched, evsel, sample, &al, thread, t, state);

out:
        if (sched->hist_time.start == 0 && t >= ptime->start)
                sched->hist_time.start = t;
        if (ptime->end == 0 || t <= ptime->end)
                sched->hist_time.end = t;

        if (tr) {
                /* time of this sched_switch event becomes last time task seen */
                tr->last_time = sample->time;

                /* last state is used to determine where to account wait time */
                tr->last_state = state;

                /* sched out event for task so reset ready to run time */
                tr->ready_to_run = 0;
        }

        perf_evsel__save_time(evsel, sample->time, sample->cpu);

        return rc;
}

static int timehist_sched_switch_event(struct perf_tool *tool,
                             union perf_event *event,
                             struct evsel *evsel,
                             struct perf_sample *sample,
                             struct machine *machine __maybe_unused)
{
        return timehist_sched_change_event(tool, event, evsel, sample, machine);
}

static int process_lost(struct perf_tool *tool __maybe_unused,
                        union perf_event *event,
                        struct perf_sample *sample,
                        struct machine *machine __maybe_unused)
{
        char tstr[64];

        timestamp__scnprintf_usec(sample->time, tstr, sizeof(tstr));
        printf("%15s ", tstr);
        printf("lost %" PRI_lu64 " events on cpu %d\n", event->lost.lost, sample->cpu);

        return 0;
}


static void print_thread_runtime(struct thread *t,
                                 struct thread_runtime *r)
{
        double mean = avg_stats(&r->run_stats);
        float stddev;

        printf("%*s   %5d  %9" PRIu64 " ",
               comm_width, timehist_get_commstr(t), t->ppid,
               (u64) r->run_stats.n);

        print_sched_time(r->total_run_time, 8);
        stddev = rel_stddev_stats(stddev_stats(&r->run_stats), mean);
        print_sched_time(r->run_stats.min, 6);
        printf(" ");
        print_sched_time((u64) mean, 6);
        printf(" ");
        print_sched_time(r->run_stats.max, 6);
        printf("  ");
        printf("%5.2f", stddev);
        printf("   %5" PRIu64, r->migrations);
        printf("\n");
}

static void print_thread_waittime(struct thread *t,
                                  struct thread_runtime *r)
{
        printf("%*s   %5d  %9" PRIu64 " ",
               comm_width, timehist_get_commstr(t), t->ppid,
               (u64) r->run_stats.n);

        print_sched_time(r->total_run_time, 8);
        print_sched_time(r->total_sleep_time, 6);
        printf(" ");
        print_sched_time(r->total_iowait_time, 6);
        printf(" ");
        print_sched_time(r->total_preempt_time, 6);
        printf(" ");
        print_sched_time(r->total_delay_time, 6);
        printf("\n");
}

struct total_run_stats {
        struct perf_sched *sched;
        u64  sched_count;
        u64  task_count;
        u64  total_run_time;
};

static int __show_thread_runtime(struct thread *t, void *priv)
{
        struct total_run_stats *stats = priv;
        struct thread_runtime *r;

        if (thread__is_filtered(t))
                return 0;

        r = thread__priv(t);
        if (r && r->run_stats.n) {
                stats->task_count++;
                stats->sched_count += r->run_stats.n;
                stats->total_run_time += r->total_run_time;

                if (stats->sched->show_state)
                        print_thread_waittime(t, r);
                else
                        print_thread_runtime(t, r);
        }

        return 0;
}

static int show_thread_runtime(struct thread *t, void *priv)
{
        if (t->dead)
                return 0;

        return __show_thread_runtime(t, priv);
}

static int show_deadthread_runtime(struct thread *t, void *priv)
{
        if (!t->dead)
                return 0;

        return __show_thread_runtime(t, priv);
}

static size_t callchain__fprintf_folded(FILE *fp, struct callchain_node *node)
{
        const char *sep = " <- ";
        struct callchain_list *chain;
        size_t ret = 0;
        char bf[1024];
        bool first;

        if (node == NULL)
                return 0;

        ret = callchain__fprintf_folded(fp, node->parent);
        first = (ret == 0);

        list_for_each_entry(chain, &node->val, list) {
                if (chain->ip >= PERF_CONTEXT_MAX)
                        continue;
                if (chain->ms.sym && chain->ms.sym->ignore)
                        continue;
                ret += fprintf(fp, "%s%s", first ? "" : sep,
                               callchain_list__sym_name(chain, bf, sizeof(bf),
                                                        false));
                first = false;
        }

        return ret;
}

static size_t timehist_print_idlehist_callchain(struct rb_root_cached *root)
{
        size_t ret = 0;
        FILE *fp = stdout;
        struct callchain_node *chain;
        struct rb_node *rb_node = rb_first_cached(root);

        printf("  %16s  %8s  %s\n", "Idle time (msec)", "Count", "Callchains");
        printf("  %.16s  %.8s  %.50s\n", graph_dotted_line, graph_dotted_line,
               graph_dotted_line);

        while (rb_node) {
                chain = rb_entry(rb_node, struct callchain_node, rb_node);
                rb_node = rb_next(rb_node);

                ret += fprintf(fp, "  ");
                print_sched_time(chain->hit, 12);
                ret += 16;  /* print_sched_time returns 2nd arg + 4 */
                ret += fprintf(fp, " %8d  ", chain->count);
                ret += callchain__fprintf_folded(fp, chain);
                ret += fprintf(fp, "\n");
        }

        return ret;
}

static void timehist_print_summary(struct perf_sched *sched,
                                   struct perf_session *session)
{
        struct machine *m = &session->machines.host;
        struct total_run_stats totals;
        u64 task_count;
        struct thread *t;
        struct thread_runtime *r;
        int i;
        u64 hist_time = sched->hist_time.end - sched->hist_time.start;

        memset(&totals, 0, sizeof(totals));
        totals.sched = sched;

        if (sched->idle_hist) {
                printf("\nIdle-time summary\n");
                printf("%*s  parent  sched-out  ", comm_width, "comm");
                printf("  idle-time   min-idle    avg-idle    max-idle  stddev  migrations\n");
        } else if (sched->show_state) {
                printf("\nWait-time summary\n");
                printf("%*s  parent   sched-in  ", comm_width, "comm");
                printf("   run-time      sleep      iowait     preempt       delay\n");
        } else {
                printf("\nRuntime summary\n");
                printf("%*s  parent   sched-in  ", comm_width, "comm");
                printf("   run-time    min-run     avg-run     max-run  stddev  migrations\n");
        }
        printf("%*s            (count)  ", comm_width, "");
        printf("     (msec)     (msec)      (msec)      (msec)       %s\n",
               sched->show_state ? "(msec)" : "%");
        printf("%.117s\n", graph_dotted_line);

        machine__for_each_thread(m, show_thread_runtime, &totals);
        task_count = totals.task_count;
        if (!task_count)
                printf("<no still running tasks>\n");

        printf("\nTerminated tasks:\n");
        machine__for_each_thread(m, show_deadthread_runtime, &totals);
        if (task_count == totals.task_count)
                printf("<no terminated tasks>\n");

        /* CPU idle stats not tracked when samples were skipped */
        if (sched->skipped_samples && !sched->idle_hist)
                return;

        printf("\nIdle stats:\n");
        for (i = 0; i < idle_max_cpu; ++i) {
                t = idle_threads[i];
                if (!t)
                        continue;

                r = thread__priv(t);
                if (r && r->run_stats.n) {
                        totals.sched_count += r->run_stats.n;
                        printf("    CPU %2d idle for ", i);
                        print_sched_time(r->total_run_time, 6);
                        printf(" msec  (%6.2f%%)\n", 100.0 * r->total_run_time / hist_time);
                } else
                        printf("    CPU %2d idle entire time window\n", i);
        }

        if (sched->idle_hist && sched->show_callchain) {
                callchain_param.mode  = CHAIN_FOLDED;
                callchain_param.value = CCVAL_PERIOD;

                callchain_register_param(&callchain_param);

                printf("\nIdle stats by callchain:\n");
                for (i = 0; i < idle_max_cpu; ++i) {
                        struct idle_thread_runtime *itr;

                        t = idle_threads[i];
                        if (!t)
                                continue;

                        itr = thread__priv(t);
                        if (itr == NULL)
                                continue;

                        callchain_param.sort(&itr->sorted_root.rb_root, &itr->callchain,
                                             0, &callchain_param);

                        printf("  CPU %2d:", i);
                        print_sched_time(itr->tr.total_run_time, 6);
                        printf(" msec\n");
                        timehist_print_idlehist_callchain(&itr->sorted_root);
                        printf("\n");
                }
        }

        printf("\n"
               "    Total number of unique tasks: %" PRIu64 "\n"
               "Total number of context switches: %" PRIu64 "\n",
               totals.task_count, totals.sched_count);

        printf("           Total run time (msec): ");
        print_sched_time(totals.total_run_time, 2);
        printf("\n");

        printf("    Total scheduling time (msec): ");
        print_sched_time(hist_time, 2);
        printf(" (x %d)\n", sched->max_cpu);
}

typedef int (*sched_handler)(struct perf_tool *tool,
                          union perf_event *event,
                          struct evsel *evsel,
                          struct perf_sample *sample,
                          struct machine *machine);

static int perf_timehist__process_sample(struct perf_tool *tool,
                                         union perf_event *event,
                                         struct perf_sample *sample,
                                         struct evsel *evsel,
                                         struct machine *machine)
{
        struct perf_sched *sched = container_of(tool, struct perf_sched, tool);
        int err = 0;
        int this_cpu = sample->cpu;

        if (this_cpu > sched->max_cpu)
                sched->max_cpu = this_cpu;

        if (evsel->handler != NULL) {
                sched_handler f = evsel->handler;

                err = f(tool, event, evsel, sample, machine);
        }

        return err;
}

static int timehist_check_attr(struct perf_sched *sched,
                               struct evlist *evlist)
{
        struct evsel *evsel;
        struct evsel_runtime *er;

        list_for_each_entry(evsel, &evlist->core.entries, core.node) {
                er = perf_evsel__get_runtime(evsel);
                if (er == NULL) {
                        pr_err("Failed to allocate memory for evsel runtime data\n");
                        return -1;
                }

                if (sched->show_callchain && !evsel__has_callchain(evsel)) {
                        pr_info("Samples do not have callchains.\n");
                        sched->show_callchain = 0;
                        symbol_conf.use_callchain = 0;
                }
        }

        return 0;
}

static int perf_sched__timehist(struct perf_sched *sched)
{
        const struct evsel_str_handler handlers[] = {
                { "sched:sched_switch",       timehist_sched_switch_event, },
                { "sched:sched_wakeup",       timehist_sched_wakeup_event, },
                { "sched:sched_wakeup_new",   timehist_sched_wakeup_event, },
        };
        const struct evsel_str_handler migrate_handlers[] = {
                { "sched:sched_migrate_task", timehist_migrate_task_event, },
        };
        struct perf_data data = {
                .path  = input_name,
                .mode  = PERF_DATA_MODE_READ,
                .force = sched->force,
        };

        struct perf_session *session;
        struct evlist *evlist;
        int err = -1;

        /*
         * event handlers for timehist option
         */
        sched->tool.sample       = perf_timehist__process_sample;
        sched->tool.mmap         = perf_event__process_mmap;
        sched->tool.comm         = perf_event__process_comm;
        sched->tool.exit         = perf_event__process_exit;
        sched->tool.fork         = perf_event__process_fork;
        sched->tool.lost         = process_lost;
        sched->tool.attr         = perf_event__process_attr;
        sched->tool.tracing_data = perf_event__process_tracing_data;
        sched->tool.build_id     = perf_event__process_build_id;

        sched->tool.ordered_events = true;
        sched->tool.ordering_requires_timestamps = true;

        symbol_conf.use_callchain = sched->show_callchain;

        session = perf_session__new(&data, false, &sched->tool);
        if (IS_ERR(session))
                return PTR_ERR(session);

        evlist = session->evlist;

        symbol__init(&session->header.env);