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Filename : schedtimes.stp
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#!/usr/bin/stap

############################################################
# Schedtimes.stp
#
# Copyright (C) 2009, 2014 Red Hat, Inc.
#
# This program is free software you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.

# Authors: Jason Baron <jbaron@redhat.com>
#          Josh Stone <jistone@redhat.com>
# profiles threads and displays their run times, queued times,
# wait times, including i/o wait times.
# Has two modes. When no arguments are given it profiles all
# threads. Alternatively, you can pass -c "program name"
############################################################

//constants
global DEAD=-1, RUNNING=1, QUEUED=2, SLEEPING=3

global run_time, queued_time, sleep_time, iowait_time
global pid_state, pid_names


// For new enough kernels, roughly 2.6.32+, the @defined(@task->in_iowait)
// tests will succeed and reduce these macros to nothing, including these
// pid-iowait arrays.  For older kernels, the rq fallback will remain.
global pid_in_iowait
global pid_iowait_count

@define in_iowait(task) %(
  @choose_defined(@task->in_iowait,
    (pid_in_iowait[@task->pid] ? pid_in_iowait[@task->pid]-- : 0))
%)

@define clear_iowait(rq, task) %(
    if (!@defined(@task->in_iowait))
      pid_iowait_count[@task->pid] = @nr_iowait(@rq)
%)

@define set_iowait(rq, task) %(
    if (!@defined(@task->in_iowait))
      pid_in_iowait[@task->pid] = (@nr_iowait(@rq) > pid_iowait_count[@task->pid])
%)

@define nr_iowait(rq) %(
    atomic_read(&@cast(@rq, "rq")->nr_iowait)
%)


global previous_timestamp

function timestamp()
{
  return cpu_clock_us(0)
}

function update_times(pid, now)
{
  delta = now - previous_timestamp[pid]
  previous_timestamp[pid] = now

  if ((state = pid_state[pid]) > 0) {
    if (state == SLEEPING)
      sleep_time[pid] += delta
    else if (state == QUEUED)
      queued_time[pid] += delta
    else if (state == RUNNING)
      run_time[pid] += delta
  }

  return delta
}


function task_targeted(task)
{
  pid = task_pid(task)
  if (pid && (!target() || target_set_pid(pid))) {
    pid_names[task_tid(task)] = task_execname(task)
    return 1
  }
  return 0
}

// Update the task name after exec
probe kernel.trace("sched_process_exec")!,
      kprocess.exec_complete
{
  if (tid() in pid_names)
    pid_names[tid()] = execname()
}


probe kernel.trace("sched_switch")
{
  // Task $prev is scheduled off this cpu
  if (task_targeted($prev)) {
    pid = $prev->pid
    state = $prev->state
    update_times(pid, timestamp())

    if (state > 0) {
      @set_iowait($rq, $prev)
      pid_state[pid] = SLEEPING
    } else if (state == 0) {
      pid_state[pid] = QUEUED
    } else {
      pid_state[pid] = DEAD
    }
  }

  // Task $next is scheduled onto this cpu
  if (task_targeted($next)) {
    pid = $next->pid
    update_times(pid, timestamp())

    @clear_iowait($rq, $next)
    pid_state[pid] = RUNNING
  }
}

probe kernel.trace("sched_wakeup")
{
  // Task $p is awakened
  if (@choose_defined($success, 1) && task_targeted($p)) {
    pid = $p->pid
    delta = update_times(pid, timestamp())
    if (pid_state[pid] == SLEEPING && @in_iowait($p)) {
      iowait_time[pid] += delta
    }
    pid_state[pid] = QUEUED
  }
}

// Give task $p a final accounting
probe kernel.trace("sched_process_exit")
{
  if (task_targeted($p)) {
    pid = $p->pid
    update_times(pid, timestamp())
    pid_state[pid] = DEAD
  }
}

probe end
{
  t = timestamp()
  printf ("\n%16s: %6s %10s %10s %10s %10s %10s\n\n",
         "execname", "pid", "run(us)", "sleep(us)", "iowait(us)",
         "queued(us)", "total(us)")
  foreach (pid+ in pid_state) {
    update_times(pid, t)
    printf("%16s: %6d %10d %10d %10d %10d %10d\n", pid_names[pid], pid,
           run_time[pid], sleep_time[pid], iowait_time[pid], queued_time[pid],
           (run_time[pid] + sleep_time[pid] + queued_time[pid]))
  }
}