// Task time query and utility functions.
// Copyright (C) 2009, 2010 Red Hat Inc.
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.

// <tapsetdescription>
// Task time query and utility functions provide information about
// the time resource usage of the current task. These functions provide
// information about the user time and system time of the current
// task. And provide utility functions to turn the reported times
// into miliseconds and create human readable string representations
// of task time used. The reported times are approximates and should
// be used for "coarse grained" measurements only. The reported user
// and system time are only for the current task, not for the process
// as a whole nor of any time spend by children of the current task.
// </tapsetdescription>

%{
#include <linux/sched.h>		/* includes asm/cputime.h */
#include <linux/time.h>

/* RHEL4 (2.6.9) kernels don't have cputime_to_msecs */
#ifndef cputime_to_msecs
#define cputime_to_msecs(__ct)		jiffies_to_msecs(__ct)
#endif
%}

/**
 * sfunction task_utime - User time of the current task
 *
 * Description: Returns the user time of the current task in cputime.
 * Does not include any time used by other tasks in this process, nor
 * does it include any time of the children of this task.
 */
function task_utime:long ()
%{ /* pure */ /* unprivileged */
  STAP_RETVALUE = current->utime;
%}

/**
 * sfunction task_utime - User time of the given task
 *
 * @tid: Thread id of the given task
 *
 * Description: Returns the user time of the given task in cputime,
 * or zero if the task doesn't exist.
 * Does not include any time used by other tasks in this process, nor
 * does it include any time of the children of this task.
 */
function task_utime_tid:long(tid:long)
{
  task = pid2task(tid);
  if (task != 0)
    return @cast(task, "task_struct", "kernel<linux/sched.h>")->utime;
  else
    return 0;
}

/**
 * sfunction task_stime - System time of the current task
 *
 * Description: Returns the system time of the current task in cputime.
 * Does not include any time used by other tasks in this process, nor
 * does it include any time of the children of this task.
 */
function task_stime:long ()
%{ /* pure */ /* unprivileged */
  STAP_RETVALUE = current->stime;
%}

/**
 * sfunction task_stime_tid - System time of the given task
 *
 * @tid: Thread id of the given task
 *
 * Description: Returns the system time of the given task in cputime,
 * or zero if the task doesn't exist.
 * Does not include any time used by other tasks in this process, nor
 * does it include any time of the children of this task.
 */
function task_stime_tid:long(tid:long)
{
  task = pid2task(tid);
  if (task != 0)
    return @cast(task, "task_struct", "kernel<linux/sched.h>")->stime;
  else
    return 0;
}

/**
 * sfunction cputime_to_msecs - Translates the given cputime into milliseconds
 * @cputime: Time to convert to milliseconds.
 */
function cputime_to_msecs:long (cputime:long)
%{ /* pure */ /* unprivileged */
  STAP_RETVALUE = cputime_to_msecs (STAP_ARG_cputime);
%}

/**
 * sfunction msecs_to_string - Human readable string for given milliseconds
 *
 * @msecs: Number of milliseconds to translate.
 *
 * Description: Returns a string representing the number of
 * milliseconds as a human readable string consisting of "XmY.ZZZs",
 * where X is the number of minutes, Y is the number of seconds and
 * ZZZ is the number of milliseconds.
 */
function msecs_to_string:string (msecs:long)
{
  ms = msecs % 1000;
  secs = msecs / 1000;
  mins = secs / 60;
  secs = secs % 60;
  return sprintf("%dm%d.%.3ds", mins, secs, ms);
}

/**
 * sfunction cputime_to_string - Human readable string for given cputime
 *
 * @cputime: Time to translate.
 *
 * Description: Equivalent to calling:
 * msec_to_string (cputime_to_msecs (cputime).
 */
function cputime_to_string:string (cputime:long)
{
  return msecs_to_string (cputime_to_msecs (cputime));
}

/**
 * sfunction task_time_string - Human readable string of task time usage
 *
 * Description: Returns a human readable string showing the user and
 * system time the current task has used up to now.  For example
 * "usr: 0m12.908s, sys: 1m6.851s".
 */
function task_time_string:string ()
{
  return sprintf ("usr: %s, sys: %s",
                  cputime_to_string (task_utime()),
                  cputime_to_string (task_stime()));
}

/**
 * sfunction task_time_string_tid - Human readable string of task time usage
 *
 * @tid: Thread id of the given task
 *
 * Description: Returns a human readable string showing the user and
 * system time the given task has used up to now.  For example
 * "usr: 0m12.908s, sys: 1m6.851s".
 */
function task_time_string_tid:string (tid:long)
{
  return sprintf ("usr: %s, sys: %s",
                  cputime_to_string (task_utime_tid(tid)),
                  cputime_to_string (task_stime_tid(tid)));
}