#!/usr/bin/stap --all-modules
# Copyright (C) 2011 Red Hat, Inc.
# Written by William Cohen <wcohen@redhat.com>
#
# A little script to give an idea what periodic things are running on
# the system

global last_expire, period, funct, data

probe kernel.trace("timer_expire_entry")
{
  old_expire = last_expire[$timer]
  new_expire = gettimeofday_us()
  if (old_expire) {
    elapsed = new_expire - old_expire
    period[$timer] <<< elapsed
    funct[$timer] = $timer->function
    data[$timer] = $timer->data
  }
  last_expire[$timer] = new_expire
}

function output()
{
  printf("#%-16s %-35s %12s %10s\n", "type", "function", "period(us)", "count")
  # print out the various timers firing
  foreach([timer] in period-) {
    fname = symname(funct[timer])
    if (fname == "process_timeout") {
      fname = sprintf("%s(%d)",
        kernel_string_n(@cast(data[timer], "struct task_struct")->comm, 16),
        @cast(data[timer], "struct task_struct")->pid)
	type="process"
    } else if (fname == "delayed_work_timer_fn") {
      fname = sprintf("%s", 
        symname(@cast(data[timer], "struct delayed_work")->work->func))
	type="work_queue"
    } else {
      fname = sprintf("%s:%s", modname(funct[timer]), fname)
	type="kernel"
    }
    printf("%-16s %-35s %12d %10d\n", type, fname,
           @avg(period[timer]), @count(period[timer]))
  }
}

probe begin { printf("#monitoring timer periods\n") }
probe end { output() }

# allow optional period output from script
%( $# > 0 %?
probe timer.s($1)
{
  output();
  delete last_expire
  delete period
  delete funct
  delete data
}
%)