perf sched: Display time in milliseconds, reorganize output

[mmotm.git] / tools / perf / builtin-sched.c

#include "builtin.h"

#include "util/util.h"
#include "util/cache.h"
#include "util/symbol.h"
#include "util/thread.h"
#include "util/header.h"

#include "util/parse-options.h"

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

#include "util/trace-event.h"
#include <sys/types.h>


#define MAX_CPUS 4096

static char                     const *input_name = "perf.data";
static int                      input;
static unsigned long            page_size;
static unsigned long            mmap_window = 32;

static unsigned long            total_comm = 0;

static struct rb_root           threads;
static struct thread            *last_match;

static struct perf_header       *header;
static u64                      sample_type;

static int                      replay_mode;
static int                      lat_mode;


/*
 * Scheduler benchmarks
 */
#include <sys/resource.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/prctl.h>

#include <linux/unistd.h>

#include <semaphore.h>
#include <pthread.h>
#include <signal.h>
#include <values.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <fcntl.h>
#include <time.h>
#include <math.h>

#include <stdio.h>

#define PR_SET_NAME     15               /* Set process name */

#define BUG_ON(x)       assert(!(x))

#define DEBUG           0

typedef unsigned long long nsec_t;

static nsec_t run_measurement_overhead;
static nsec_t sleep_measurement_overhead;

static nsec_t get_nsecs(void)
{
        struct timespec ts;

        clock_gettime(CLOCK_MONOTONIC, &ts);

        return ts.tv_sec * 1000000000ULL + ts.tv_nsec;
}

static void burn_nsecs(nsec_t nsecs)
{
        nsec_t T0 = get_nsecs(), T1;

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

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

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

        nanosleep(&ts, NULL);
}

static void calibrate_run_measurement_overhead(void)
{
        nsec_t T0, T1, delta, min_delta = 1000000000ULL;
        int i;

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

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

static void calibrate_sleep_measurement_overhead(void)
{
        nsec_t T0, T1, delta, min_delta = 1000000000ULL;
        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;
        sleep_measurement_overhead = min_delta;

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

#define COMM_LEN        20
#define SYM_LEN         129

#define MAX_PID         65536

static unsigned long nr_tasks;

struct sched_event;

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

        unsigned long           nr_events;
        unsigned long           curr_event;
        struct sched_event      **events;

        pthread_t               thread;
        sem_t                   sleep_sem;

        sem_t                   ready_for_work;
        sem_t                   work_done_sem;

        nsec_t                  cpu_usage;
};

enum sched_event_type {
        SCHED_EVENT_RUN,
        SCHED_EVENT_SLEEP,
        SCHED_EVENT_WAKEUP,
};

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

static struct task_desc         *pid_to_task[MAX_PID];

static struct task_desc         **tasks;

static pthread_mutex_t          start_work_mutex = PTHREAD_MUTEX_INITIALIZER;
static nsec_t                   start_time;

static pthread_mutex_t          work_done_wait_mutex = PTHREAD_MUTEX_INITIALIZER;

static unsigned long            nr_run_events;
static unsigned long            nr_sleep_events;
static unsigned long            nr_wakeup_events;

static unsigned long            nr_sleep_corrections;
static unsigned long            nr_run_events_optimized;

static struct sched_event *
get_new_event(struct task_desc *task, nsec_t timestamp)
{
        struct sched_event *event = calloc(1, sizeof(*event));
        unsigned long idx = task->nr_events;
        size_t size;

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

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

        task->events[idx] = event;

        return event;
}

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

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

static void
add_sched_event_run(struct task_desc *task, nsec_t timestamp, u64 duration)
{
        struct sched_event *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) {
                nr_run_events_optimized++;
                curr_event->duration += duration;
                return;
        }

        event = get_new_event(task, timestamp);

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

        nr_run_events++;
}

static unsigned long targetless_wakeups;
static unsigned long multitarget_wakeups;

static void
add_sched_event_wakeup(struct task_desc *task, nsec_t timestamp,
                       struct task_desc *wakee)
{
        struct sched_event *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) {
                targetless_wakeups++;
                return;
        }
        if (wakee_event->wait_sem) {
                multitarget_wakeups++;
                return;
        }

        wakee_event->wait_sem = calloc(1, 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;

        nr_wakeup_events++;
}

static void
add_sched_event_sleep(struct task_desc *task, nsec_t timestamp,
                      u64 task_state __used)
{
        struct sched_event *event = get_new_event(task, timestamp);

        event->type = SCHED_EVENT_SLEEP;

        nr_sleep_events++;
}

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

        BUG_ON(pid >= MAX_PID);

        task = pid_to_task[pid];

        if (task)
                return task;

        task = calloc(1, sizeof(*task));
        task->pid = pid;
        task->nr = 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(task, 0, 0);

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

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

        return task;
}


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

        for (i = 0; i < nr_tasks; i++) {
                task = 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(void)
{
        struct task_desc *task1, *task2;
        unsigned long i, j;

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

static void
process_sched_event(struct task_desc *this_task __used, struct sched_event *event)
{
        int ret = 0;
        nsec_t now;
        long long delta;

        now = get_nsecs();
        delta = start_time + event->timestamp - now;

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

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

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

        sum =  ru.ru_utime.tv_sec*1e9 + ru.ru_utime.tv_usec*1e3;
        sum += ru.ru_stime.tv_sec*1e9 + ru.ru_stime.tv_usec*1e3;

        return sum;
}

static nsec_t get_cpu_usage_nsec_self(void)
{
        char filename [] = "/proc/1234567890/sched";
        unsigned long msecs, nsecs;
        char *line = NULL;
        nsec_t total = 0;
        size_t len = 0;
        ssize_t chars;
        FILE *file;
        int ret;

        sprintf(filename, "/proc/%d/sched", getpid());
        file = fopen(filename, "r");
        BUG_ON(!file);

        while ((chars = getline(&line, &len, file)) != -1) {
                ret = sscanf(line, "se.sum_exec_runtime : %ld.%06ld\n",
                        &msecs, &nsecs);
                if (ret == 2) {
                        total = msecs*1e6 + nsecs;
                        break;
                }
        }
        if (line)
                free(line);
        fclose(file);

        return total;
}

static void *thread_func(void *ctx)
{
        struct task_desc *this_task = ctx;
        nsec_t cpu_usage_0, cpu_usage_1;
        unsigned long i, ret;
        char comm2[22];

        sprintf(comm2, ":%s", this_task->comm);
        prctl(PR_SET_NAME, comm2);

again:
        ret = sem_post(&this_task->ready_for_work);
        BUG_ON(ret);
        ret = pthread_mutex_lock(&start_work_mutex);
        BUG_ON(ret);
        ret = pthread_mutex_unlock(&start_work_mutex);
        BUG_ON(ret);

        cpu_usage_0 = get_cpu_usage_nsec_self();

        for (i = 0; i < this_task->nr_events; i++) {
                this_task->curr_event = i;
                process_sched_event(this_task, this_task->events[i]);
        }

        cpu_usage_1 = get_cpu_usage_nsec_self();
        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(&work_done_wait_mutex);
        BUG_ON(ret);
        ret = pthread_mutex_unlock(&work_done_wait_mutex);
        BUG_ON(ret);

        goto again;
}

static void create_tasks(void)
{
        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)(16*1024));
        BUG_ON(err);
        err = pthread_mutex_lock(&start_work_mutex);
        BUG_ON(err);
        err = pthread_mutex_lock(&work_done_wait_mutex);
        BUG_ON(err);
        for (i = 0; i < nr_tasks; i++) {
                task = tasks[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, task);
                BUG_ON(err);
        }
}

static nsec_t cpu_usage;
static nsec_t runavg_cpu_usage;
static nsec_t parent_cpu_usage;
static nsec_t runavg_parent_cpu_usage;

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

        start_time = get_nsecs();
        cpu_usage = 0;
        pthread_mutex_unlock(&work_done_wait_mutex);

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

        cpu_usage_0 = get_cpu_usage_nsec_parent();

        pthread_mutex_unlock(&start_work_mutex);

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

        cpu_usage_1 = get_cpu_usage_nsec_parent();
        if (!runavg_cpu_usage)
                runavg_cpu_usage = cpu_usage;
        runavg_cpu_usage = (runavg_cpu_usage*9 + cpu_usage)/10;

        parent_cpu_usage = cpu_usage_1 - cpu_usage_0;
        if (!runavg_parent_cpu_usage)
                runavg_parent_cpu_usage = parent_cpu_usage;
        runavg_parent_cpu_usage = (runavg_parent_cpu_usage*9 +
                                   parent_cpu_usage)/10;

        ret = pthread_mutex_lock(&start_work_mutex);
        BUG_ON(ret);

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

static int read_events(void);

static unsigned long nr_runs;
static nsec_t sum_runtime;
static nsec_t sum_fluct;
static nsec_t run_avg;

static void run_one_test(void)
{
        nsec_t T0, T1, delta, avg_delta, fluct, std_dev;

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

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

        avg_delta = sum_runtime / nr_runs;
        if (delta < avg_delta)
                fluct = avg_delta - delta;
        else
                fluct = delta - avg_delta;
        sum_fluct += fluct;
        std_dev = sum_fluct / nr_runs / sqrt(nr_runs);
        if (!run_avg)
                run_avg = delta;
        run_avg = (run_avg*9 + delta)/10;

        printf("#%-3ld: %0.3f, ",
                nr_runs, (double)delta/1000000.0);

#if 0
        printf("%0.2f +- %0.2f, ",
                (double)avg_delta/1e6, (double)std_dev/1e6);
#endif
        printf("ravg: %0.2f, ",
                (double)run_avg/1e6);

        printf("cpu: %0.2f / %0.2f",
                (double)cpu_usage/1e6, (double)runavg_cpu_usage/1e6);

#if 0
        /*
         * rusage statistics done by the parent, these are less
         * accurate than the sum_exec_runtime based statistics:
         */
        printf(" [%0.2f / %0.2f]",
                (double)parent_cpu_usage/1e6,
                (double)runavg_parent_cpu_usage/1e6);
#endif

        printf("\n");

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

static void test_calibrations(void)
{
        nsec_t T0, T1;

        T0 = get_nsecs();
        burn_nsecs(1e6);
        T1 = get_nsecs();

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

        T0 = get_nsecs();
        sleep_nsecs(1e6);
        T1 = get_nsecs();

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

static void __cmd_replay(void)
{
        long nr_iterations = 10, i;

        calibrate_run_measurement_overhead();
        calibrate_sleep_measurement_overhead();

        test_calibrations();

        read_events();

        printf("nr_run_events:        %ld\n", nr_run_events);
        printf("nr_sleep_events:      %ld\n", nr_sleep_events);
        printf("nr_wakeup_events:     %ld\n", nr_wakeup_events);

        if (targetless_wakeups)
                printf("target-less wakeups:  %ld\n", targetless_wakeups);
        if (multitarget_wakeups)
                printf("multi-target wakeups: %ld\n", multitarget_wakeups);
        if (nr_run_events_optimized)
                printf("run events optimized: %ld\n",
                        nr_run_events_optimized);

        print_task_traces();
        add_cross_task_wakeups();

        create_tasks();
        printf("------------------------------------------------------------\n");
        for (i = 0; i < nr_iterations; i++)
                run_one_test();
}

static int
process_comm_event(event_t *event, unsigned long offset, unsigned long head)
{
        struct thread *thread;

        thread = threads__findnew(event->comm.pid, &threads, &last_match);

        dump_printf("%p [%p]: PERF_EVENT_COMM: %s:%d\n",
                (void *)(offset + head),
                (void *)(long)(event->header.size),
                event->comm.comm, event->comm.pid);

        if (thread == NULL ||
            thread__set_comm(thread, event->comm.comm)) {
                dump_printf("problem processing PERF_EVENT_COMM, skipping event.\n");
                return -1;
        }
        total_comm++;

        return 0;
}


struct raw_event_sample {
        u32 size;
        char data[0];
};

#define FILL_FIELD(ptr, field, event, data)     \
        ptr.field = (typeof(ptr.field)) raw_field_value(event, #field, data)

#define FILL_ARRAY(ptr, array, event, data)                     \
do {                                                            \
        void *__array = raw_field_ptr(event, #array, data);     \
        memcpy(ptr.array, __array, sizeof(ptr.array));  \
} while(0)

#define FILL_COMMON_FIELDS(ptr, event, data)                    \
do {                                                            \
        FILL_FIELD(ptr, common_type, event, data);              \
        FILL_FIELD(ptr, common_flags, event, data);             \
        FILL_FIELD(ptr, common_preempt_count, event, data);     \
        FILL_FIELD(ptr, common_pid, event, data);               \
        FILL_FIELD(ptr, common_tgid, event, data);              \
} while (0)



struct trace_switch_event {
        u32 size;

        u16 common_type;
        u8 common_flags;
        u8 common_preempt_count;
        u32 common_pid;
        u32 common_tgid;

        char prev_comm[16];
        u32 prev_pid;
        u32 prev_prio;
        u64 prev_state;
        char next_comm[16];
        u32 next_pid;
        u32 next_prio;
};


struct trace_wakeup_event {
        u32 size;

        u16 common_type;
        u8 common_flags;
        u8 common_preempt_count;
        u32 common_pid;
        u32 common_tgid;

        char comm[16];
        u32 pid;

        u32 prio;
        u32 success;
        u32 cpu;
};

struct trace_fork_event {
        u32 size;

        u16 common_type;
        u8 common_flags;
        u8 common_preempt_count;
        u32 common_pid;
        u32 common_tgid;

        char parent_comm[16];
        u32 parent_pid;
        char child_comm[16];
        u32 child_pid;
};

struct trace_sched_handler {
        void (*switch_event)(struct trace_switch_event *,
                             struct event *,
                             int cpu,
                             u64 timestamp,
                             struct thread *thread);

        void (*wakeup_event)(struct trace_wakeup_event *,
                             struct event *,
                             int cpu,
                             u64 timestamp,
                             struct thread *thread);

        void (*fork_event)(struct trace_fork_event *,
                           struct event *,
                           int cpu,
                           u64 timestamp,
                           struct thread *thread);
};


static void
replay_wakeup_event(struct trace_wakeup_event *wakeup_event,
                    struct event *event,
                    int cpu __used,
                    u64 timestamp __used,
                    struct thread *thread __used)
{
        struct task_desc *waker, *wakee;

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

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

        waker = register_pid(wakeup_event->common_pid, "<unknown>");
        wakee = register_pid(wakeup_event->pid, wakeup_event->comm);

        add_sched_event_wakeup(waker, timestamp, wakee);
}

static unsigned long cpu_last_switched[MAX_CPUS];

static void
replay_switch_event(struct trace_switch_event *switch_event,
                    struct event *event,
                    int cpu,
                    u64 timestamp,
                    struct thread *thread __used)
{
        struct task_desc *prev, *next;
        u64 timestamp0;
        s64 delta;

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

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

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

        if (delta < 0)
                die("hm, delta: %Ld < 0 ?\n", delta);

        if (verbose) {
                printf(" ... switch from %s/%d to %s/%d [ran %Ld nsecs]\n",
                        switch_event->prev_comm, switch_event->prev_pid,
                        switch_event->next_comm, switch_event->next_pid,
                        delta);
        }

        prev = register_pid(switch_event->prev_pid, switch_event->prev_comm);
        next = register_pid(switch_event->next_pid, switch_event->next_comm);

        cpu_last_switched[cpu] = timestamp;

        add_sched_event_run(prev, timestamp, delta);
        add_sched_event_sleep(prev, timestamp, switch_event->prev_state);
}


static void
replay_fork_event(struct trace_fork_event *fork_event,
                  struct event *event,
                  int cpu __used,
                  u64 timestamp __used,
                  struct thread *thread __used)
{
        if (verbose) {
                printf("sched_fork event %p\n", event);
                printf("... parent: %s/%d\n", fork_event->parent_comm, fork_event->parent_pid);
                printf("...  child: %s/%d\n", fork_event->child_comm, fork_event->child_pid);
        }
        register_pid(fork_event->parent_pid, fork_event->parent_comm);
        register_pid(fork_event->child_pid, fork_event->child_comm);
}

static struct trace_sched_handler replay_ops  = {
        .wakeup_event = replay_wakeup_event,
        .switch_event = replay_switch_event,
        .fork_event = replay_fork_event,
};

#define TASK_STATE_TO_CHAR_STR "RSDTtZX"

enum thread_state {
        THREAD_SLEEPING,
        THREAD_WAKED_UP,
        THREAD_SCHED_IN,
        THREAD_IGNORE
};

struct lat_snapshot {
        struct list_head        list;
        enum thread_state       state;
        u64                     wake_up_time;
        u64                     sched_in_time;
};

struct thread_latency {
        struct list_head        snapshot_list;
        struct thread           *thread;
        struct rb_node          node;
};

static struct rb_root lat_snapshot_root;

static struct thread_latency *
thread_latency_search(struct rb_root *root, struct thread *thread)
{
        struct rb_node *node = root->rb_node;

        while (node) {
                struct thread_latency *lat;

                lat = container_of(node, struct thread_latency, node);
                if (thread->pid < lat->thread->pid)
                        node = node->rb_left;
                else if (thread->pid > lat->thread->pid)
                        node = node->rb_right;
                else {
                        return lat;
                }
        }
        return NULL;
}

static void
__thread_latency_insert(struct rb_root *root, struct thread_latency *data)
{
        struct rb_node **new = &(root->rb_node), *parent = NULL;

        while (*new) {
                struct thread_latency *this;

                this = container_of(*new, struct thread_latency, node);
                parent = *new;
                if (data->thread->pid < this->thread->pid)
                        new = &((*new)->rb_left);
                else if (data->thread->pid > this->thread->pid)
                        new = &((*new)->rb_right);
                else
                        die("Double thread insertion\n");
        }

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

static void thread_latency_insert(struct thread *thread)
{
        struct thread_latency *lat;
        lat = calloc(sizeof(*lat), 1);
        if (!lat)
                die("No memory");

        lat->thread = thread;
        INIT_LIST_HEAD(&lat->snapshot_list);
        __thread_latency_insert(&lat_snapshot_root, lat);
}

static void
latency_fork_event(struct trace_fork_event *fork_event __used,
                   struct event *event __used,
                   int cpu __used,
                   u64 timestamp __used,
                   struct thread *thread __used)
{
        /* should insert the newcomer */
}

static char sched_out_state(struct trace_switch_event *switch_event)
{
        const char *str = TASK_STATE_TO_CHAR_STR;

        return str[switch_event->prev_state];
}

static void
lat_sched_out(struct thread_latency *lat,
             struct trace_switch_event *switch_event)
{
        struct lat_snapshot *snapshot;

        if (sched_out_state(switch_event) == 'R')
                return;

        snapshot = calloc(sizeof(*snapshot), 1);
        if (!snapshot)
                die("Non memory");

        list_add_tail(&snapshot->list, &lat->snapshot_list);
}

static void
lat_sched_in(struct thread_latency *lat, u64 timestamp)
{
        struct lat_snapshot *snapshot;

        if (list_empty(&lat->snapshot_list))
                return;

        snapshot = list_entry(lat->snapshot_list.prev, struct lat_snapshot,
                              list);

        if (snapshot->state != THREAD_WAKED_UP)
                return;

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

        snapshot->state = THREAD_SCHED_IN;
        snapshot->sched_in_time = timestamp;
}


static void
latency_switch_event(struct trace_switch_event *switch_event,
                     struct event *event __used,
                     int cpu __used,
                     u64 timestamp,
                     struct thread *thread __used)
{
        struct thread_latency *out_lat, *in_lat;
        struct thread *sched_out, *sched_in;

        sched_out = threads__findnew(switch_event->prev_pid, &threads, &last_match);
        sched_in = threads__findnew(switch_event->next_pid, &threads, &last_match);

        in_lat = thread_latency_search(&lat_snapshot_root, sched_in);
        if (!in_lat) {
                thread_latency_insert(sched_in);
                in_lat = thread_latency_search(&lat_snapshot_root, sched_in);
                if (!in_lat)
                        die("Internal latency tree error");
        }

        out_lat = thread_latency_search(&lat_snapshot_root, sched_out);
        if (!out_lat) {
                thread_latency_insert(sched_out);
                out_lat = thread_latency_search(&lat_snapshot_root, sched_out);
                if (!out_lat)
                        die("Internal latency tree error");
        }

        lat_sched_in(in_lat, timestamp);
        lat_sched_out(out_lat, switch_event);
}

static void
latency_wakeup_event(struct trace_wakeup_event *wakeup_event,
                     struct event *event __used,
                     int cpu __used,
                     u64 timestamp,
                     struct thread *thread __used)
{
        struct thread_latency *lat;
        struct lat_snapshot *snapshot;
        struct thread *wakee;

        /* Note for later, it may be interesting to observe the failing cases */
        if (!wakeup_event->success)
                return;

        wakee = threads__findnew(wakeup_event->pid, &threads, &last_match);
        lat = thread_latency_search(&lat_snapshot_root, wakee);
        if (!lat) {
                thread_latency_insert(wakee);
                return;
        }

        if (list_empty(&lat->snapshot_list))
                return;

        snapshot = list_entry(lat->snapshot_list.prev, struct lat_snapshot,
                              list);

        if (snapshot->state != THREAD_SLEEPING)
                return;

        snapshot->state = THREAD_WAKED_UP;
        snapshot->wake_up_time = timestamp;
}

static struct trace_sched_handler lat_ops  = {
        .wakeup_event = latency_wakeup_event,
        .switch_event = latency_switch_event,
        .fork_event = latency_fork_event,
};

static void output_lat_thread(struct thread_latency *lat)
{
        struct lat_snapshot *shot;
        int count = 0;
        int i;
        int ret;
        u64 max = 0, avg;
        u64 total = 0, delta;

        list_for_each_entry(shot, &lat->snapshot_list, list) {
                if (shot->state != THREAD_SCHED_IN)
                        continue;

                count++;

                delta = shot->sched_in_time - shot->wake_up_time;
                if (delta > max)
                        max = delta;
                total += delta;
        }

        if (!count)
                return;

        ret = printf(" %s ", lat->thread->comm);

        for (i = 0; i < 19 - ret; i++)
                printf(" ");

        avg = total / count;

        printf("|%9.3f ms |%9d | avg:%9.3f ms | max:%9.3f ms |\n",
                0.0, count, (double)avg/1e9, (double)max/1e9);
}

static void __cmd_lat(void)
{
        struct rb_node *next;

        setup_pager();
        read_events();

        printf("-----------------------------------------------------------------------------------\n");
        printf(" Task              |  runtime ms | switches | average delay ms | maximum delay ms |\n");
        printf("-----------------------------------------------------------------------------------\n");

        next = rb_first(&lat_snapshot_root);

        while (next) {
                struct thread_latency *lat;

                lat = rb_entry(next, struct thread_latency, node);
                output_lat_thread(lat);
                next = rb_next(next);
        }

        printf("-----------------------------------------------------------------------------------\n");
}

static struct trace_sched_handler *trace_handler;

static void
process_sched_wakeup_event(struct raw_event_sample *raw,
                           struct event *event,
                           int cpu __used,
                           u64 timestamp __used,
                           struct thread *thread __used)
{
        struct trace_wakeup_event wakeup_event;

        FILL_COMMON_FIELDS(wakeup_event, event, raw->data);

        FILL_ARRAY(wakeup_event, comm, event, raw->data);
        FILL_FIELD(wakeup_event, pid, event, raw->data);
        FILL_FIELD(wakeup_event, prio, event, raw->data);
        FILL_FIELD(wakeup_event, success, event, raw->data);
        FILL_FIELD(wakeup_event, cpu, event, raw->data);

        trace_handler->wakeup_event(&wakeup_event, event, cpu, timestamp, thread);
}

static void
process_sched_switch_event(struct raw_event_sample *raw,
                           struct event *event,
                           int cpu __used,
                           u64 timestamp __used,
                           struct thread *thread __used)
{
        struct trace_switch_event switch_event;

        FILL_COMMON_FIELDS(switch_event, event, raw->data);

        FILL_ARRAY(switch_event, prev_comm, event, raw->data);
        FILL_FIELD(switch_event, prev_pid, event, raw->data);
        FILL_FIELD(switch_event, prev_prio, event, raw->data);
        FILL_FIELD(switch_event, prev_state, event, raw->data);
        FILL_ARRAY(switch_event, next_comm, event, raw->data);
        FILL_FIELD(switch_event, next_pid, event, raw->data);
        FILL_FIELD(switch_event, next_prio, event, raw->data);

        trace_handler->switch_event(&switch_event, event, cpu, timestamp, thread);
}

static void
process_sched_fork_event(struct raw_event_sample *raw,
                         struct event *event,
                         int cpu __used,
                         u64 timestamp __used,
                         struct thread *thread __used)
{
        struct trace_fork_event fork_event;

        FILL_COMMON_FIELDS(fork_event, event, raw->data);

        FILL_ARRAY(fork_event, parent_comm, event, raw->data);
        FILL_FIELD(fork_event, parent_pid, event, raw->data);
        FILL_ARRAY(fork_event, child_comm, event, raw->data);
        FILL_FIELD(fork_event, child_pid, event, raw->data);

        trace_handler->fork_event(&fork_event, event, cpu, timestamp, thread);
}

static void
process_sched_exit_event(struct event *event,
                         int cpu __used,
                         u64 timestamp __used,
                         struct thread *thread __used)
{
        if (verbose)
                printf("sched_exit event %p\n", event);
}

static void
process_raw_event(event_t *raw_event __used, void *more_data,
                  int cpu, u64 timestamp, struct thread *thread)
{
        struct raw_event_sample *raw = more_data;
        struct event *event;
        int type;

        type = trace_parse_common_type(raw->data);
        event = trace_find_event(type);

        if (!strcmp(event->name, "sched_switch"))
                process_sched_switch_event(raw, event, cpu, timestamp, thread);
        if (!strcmp(event->name, "sched_wakeup"))
                process_sched_wakeup_event(raw, event, cpu, timestamp, thread);
        if (!strcmp(event->name, "sched_wakeup_new"))
                process_sched_wakeup_event(raw, event, cpu, timestamp, thread);
        if (!strcmp(event->name, "sched_process_fork"))
                process_sched_fork_event(raw, event, cpu, timestamp, thread);
        if (!strcmp(event->name, "sched_process_exit"))
                process_sched_exit_event(event, cpu, timestamp, thread);
}

static int
process_sample_event(event_t *event, unsigned long offset, unsigned long head)
{
        char level;
        int show = 0;
        struct dso *dso = NULL;
        struct thread *thread;
        u64 ip = event->ip.ip;
        u64 timestamp = -1;
        u32 cpu = -1;
        u64 period = 1;
        void *more_data = event->ip.__more_data;
        int cpumode;

        thread = threads__findnew(event->ip.pid, &threads, &last_match);

        if (sample_type & PERF_SAMPLE_TIME) {
                timestamp = *(u64 *)more_data;
                more_data += sizeof(u64);
        }

        if (sample_type & PERF_SAMPLE_CPU) {
                cpu = *(u32 *)more_data;
                more_data += sizeof(u32);
                more_data += sizeof(u32); /* reserved */
        }

        if (sample_type & PERF_SAMPLE_PERIOD) {
                period = *(u64 *)more_data;
                more_data += sizeof(u64);
        }

        dump_printf("%p [%p]: PERF_EVENT_SAMPLE (IP, %d): %d/%d: %p period: %Ld\n",
                (void *)(offset + head),
                (void *)(long)(event->header.size),
                event->header.misc,
                event->ip.pid, event->ip.tid,
                (void *)(long)ip,
                (long long)period);

        dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);

        if (thread == NULL) {
                eprintf("problem processing %d event, skipping it.\n",
                        event->header.type);
                return -1;
        }

        cpumode = event->header.misc & PERF_EVENT_MISC_CPUMODE_MASK;

        if (cpumode == PERF_EVENT_MISC_KERNEL) {
                show = SHOW_KERNEL;
                level = 'k';

                dso = kernel_dso;

                dump_printf(" ...... dso: %s\n", dso->name);

        } else if (cpumode == PERF_EVENT_MISC_USER) {

                show = SHOW_USER;
                level = '.';

        } else {
                show = SHOW_HV;
                level = 'H';

                dso = hypervisor_dso;

                dump_printf(" ...... dso: [hypervisor]\n");
        }

        if (sample_type & PERF_SAMPLE_RAW)
                process_raw_event(event, more_data, cpu, timestamp, thread);

        return 0;
}

static int
process_event(event_t *event, unsigned long offset, unsigned long head)
{
        trace_event(event);

        switch (event->header.type) {
        case PERF_EVENT_MMAP ... PERF_EVENT_LOST:
                return 0;

        case PERF_EVENT_COMM:
                return process_comm_event(event, offset, head);

        case PERF_EVENT_EXIT ... PERF_EVENT_READ:
                return 0;

        case PERF_EVENT_SAMPLE:
                return process_sample_event(event, offset, head);

        case PERF_EVENT_MAX:
        default:
                return -1;
        }

        return 0;
}

static int read_events(void)
{
        int ret, rc = EXIT_FAILURE;
        unsigned long offset = 0;
        unsigned long head = 0;
        struct stat perf_stat;
        event_t *event;
        uint32_t size;
        char *buf;

        trace_report();
        register_idle_thread(&threads, &last_match);

        input = open(input_name, O_RDONLY);
        if (input < 0) {
                perror("failed to open file");
                exit(-1);
        }

        ret = fstat(input, &perf_stat);
        if (ret < 0) {
                perror("failed to stat file");
                exit(-1);
        }

        if (!perf_stat.st_size) {
                fprintf(stderr, "zero-sized file, nothing to do!\n");
                exit(0);
        }
        header = perf_header__read(input);
        head = header->data_offset;
        sample_type = perf_header__sample_type(header);

        if (!(sample_type & PERF_SAMPLE_RAW))
                die("No trace sample to read. Did you call perf record "
                    "without -R?");

        if (load_kernel() < 0) {
                perror("failed to load kernel symbols");
                return EXIT_FAILURE;
        }

remap:
        buf = (char *)mmap(NULL, page_size * mmap_window, PROT_READ,
                           MAP_SHARED, input, offset);
        if (buf == MAP_FAILED) {
                perror("failed to mmap file");
                exit(-1);
        }

more:
        event = (event_t *)(buf + head);

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

        if (head + event->header.size >= page_size * mmap_window) {
                unsigned long shift = page_size * (head / page_size);
                int res;

                res = munmap(buf, page_size * mmap_window);
                assert(res == 0);

                offset += shift;
                head -= shift;
                goto remap;
        }

        size = event->header.size;


        if (!size || process_event(event, offset, head) < 0) {

                /*
                 * assume we lost track of the stream, check alignment, and
                 * increment a single u64 in the hope to catch on again 'soon'.
                 */

                if (unlikely(head & 7))
                        head &= ~7ULL;

                size = 8;
        }

        head += size;

        if (offset + head < (unsigned long)perf_stat.st_size)
                goto more;

        rc = EXIT_SUCCESS;
        close(input);

        return rc;
}

static const char * const sched_usage[] = {
        "perf sched [<options>] <command>",
        NULL
};

static const struct option options[] = {
        OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
                    "dump raw trace in ASCII"),
        OPT_BOOLEAN('r', "replay", &replay_mode,
                    "replay sched behaviour from traces"),
        OPT_BOOLEAN('l', "latency", &lat_mode,
                    "measure various latencies"),
        OPT_BOOLEAN('v', "verbose", &verbose,
                    "be more verbose (show symbol address, etc)"),
        OPT_END()
};

int cmd_sched(int argc, const char **argv, const char *prefix __used)
{
        symbol__init();
        page_size = getpagesize();

        argc = parse_options(argc, argv, options, sched_usage, 0);
        if (argc) {
                /*
                 * Special case: if there's an argument left then assume tha
                 * it's a symbol filter:
                 */
                if (argc > 1)
                        usage_with_options(sched_usage, options);
        }

        if (replay_mode)
                trace_handler = &replay_ops;
        else if (lat_mode)
                trace_handler = &lat_ops;
        else
                usage_with_options(sched_usage, options);

        if (replay_mode)
                __cmd_replay();
        else if (lat_mode)
                __cmd_lat();

        return 0;
}