写在前面

tracepoint是Linux内核中预定义的静态探测点，分布于内核各个子系统中。每个tracepoint通常包含开关-enable，过滤器-filter等。如下是/sys/kernel/tracing/events/sched子系统中支持的各种tracepoint事件：

coral:/sys/kernel/tracing/events/sched $ ls
core_ctl_eval_need       sched_boost_task          sched_kthread_stop            sched_load_se          sched_process_fork  sched_stick_numa              sched_wait_task
core_ctl_set_boost       sched_capacity_update     sched_kthread_stop_ret        sched_migrate_task     sched_process_free  sched_swap_numa               sched_wake_idle_without_ipi
core_ctl_set_busy        sched_cpu_util            sched_load_balance            sched_move_numa        sched_process_wait  sched_switch                  sched_wakeup
core_ctl_update_nr_need  sched_energy_diff         sched_load_balance_nohz_kick  sched_overutilized     sched_stat_blocked  sched_task_util               sched_wakeup_new
enable                   sched_enq_deq_task        sched_load