/*

 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "memory/allocation.hpp"

#include "runtime/init.hpp"

#include "runtime/task.hpp"

#include "runtime/timer.hpp"

#ifdef TARGET_OS_FAMILY_linux

# include "os_linux.inline.hpp"

# include "thread_linux.inline.hpp"

#endif

#ifdef TARGET_OS_FAMILY_solaris

# include "os_solaris.inline.hpp"

# include "thread_solaris.inline.hpp"

#endif

#ifdef TARGET_OS_FAMILY_windows

# include "os_windows.inline.hpp"

# include "thread_windows.inline.hpp"

#endif

int PeriodicTask::_num_tasks = 0;

PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks];

#ifndef PRODUCT

elapsedTimer PeriodicTask::_timer;

int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval];

int PeriodicTask::_ticks;

void PeriodicTask::print_intervals() {

  if (ProfilerCheckIntervals) {

    for (int i = 0; i < PeriodicTask::max_interval; i++) {

      int n = _intervalHistogram[i];

      if (n > 0) tty->print_cr("%3d: %5d (%4.1f%%)", i, n, 100.0 * n / _ticks);

    }

  }

}

#endif

void PeriodicTask::real_time_tick(size_t delay_time) {

#ifndef PRODUCT

  if (ProfilerCheckIntervals) {

    _ticks++;

    _timer.stop();

    int ms = (int)(_timer.seconds() * 1000.0);

    _timer.reset();

    _timer.start();

    if (ms >= PeriodicTask::max_interval) ms = PeriodicTask::max_interval - 1;

    _intervalHistogram[ms]++;

  }

#endif

  int orig_num_tasks = _num_tasks;

  for(int index = 0; index < _num_tasks; index++) {

    _tasks[index]->execute_if_pending(delay_time);

    if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself

      index--;  // re-do current slot as it has changed

      orig_num_tasks = _num_tasks;

    }

  }

}

PeriodicTask::PeriodicTask(size_t interval_time) :

  _counter(0), _interval(interval_time) {

  // Sanity check the interval time

  assert(_interval >= PeriodicTask::min_interval &&

         _interval <= PeriodicTask::max_interval &&

         _interval %  PeriodicTask::interval_gran == 0,

              "improper PeriodicTask interval time");

}

PeriodicTask::~PeriodicTask() {

  if (is_enrolled())

    disenroll();

}

bool PeriodicTask::is_enrolled() const {

  for(int index = 0; index < _num_tasks; index++)

    if (_tasks[index] == this) return true;

  return false;

}

void PeriodicTask::enroll() {

  assert(WatcherThread::watcher_thread() == NULL, "dynamic enrollment of tasks not yet supported");

  if (_num_tasks == PeriodicTask::max_tasks)

    fatal("Overflow in PeriodicTask table");

  _tasks[_num_tasks++] = this;

}

void PeriodicTask::disenroll() {

  assert(WatcherThread::watcher_thread() == NULL ||

         Thread::current() == WatcherThread::watcher_thread(),

         "dynamic disenrollment currently only handled from WatcherThread from within task() method");

  int index;

  for(index = 0; index < _num_tasks && _tasks[index] != this; index++);

  if (index == _num_tasks) return;

  _num_tasks--;

  for (; index < _num_tasks; index++) {

    _tasks[index] = _tasks[index+1];

  }

}