task.cpp revision 2721:f08d439fab8c 
1/*
2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25#include "precompiled.hpp"
26#include "memory/allocation.hpp"
27#include "runtime/init.hpp"
28#include "runtime/task.hpp"
29#include "runtime/timer.hpp"
30#ifdef TARGET_OS_FAMILY_linux
31# include "os_linux.inline.hpp"
32# include "thread_linux.inline.hpp"
33#endif
34#ifdef TARGET_OS_FAMILY_solaris
35# include "os_solaris.inline.hpp"
36# include "thread_solaris.inline.hpp"
37#endif
38#ifdef TARGET_OS_FAMILY_windows
39# include "os_windows.inline.hpp"
40# include "thread_windows.inline.hpp"
41#endif
42#ifdef TARGET_OS_FAMILY_bsd
43# include "os_bsd.inline.hpp"
44# include "thread_bsd.inline.hpp"
45#endif
46
47int PeriodicTask::_num_tasks = 0;
48PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks];
49#ifndef PRODUCT
50elapsedTimer PeriodicTask::_timer;
51int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval];
52int PeriodicTask::_ticks;
53
54void PeriodicTask::print_intervals() {
55  if (ProfilerCheckIntervals) {
56    for (int i = 0; i < PeriodicTask::max_interval; i++) {
57      int n = _intervalHistogram[i];
58      if (n > 0) tty->print_cr("%3d: %5d (%4.1f%%)", i, n, 100.0 * n / _ticks);
59    }
60  }
61}
62#endif
63
64void PeriodicTask::real_time_tick(size_t delay_time) {
65#ifndef PRODUCT
66  if (ProfilerCheckIntervals) {
67    _ticks++;
68    _timer.stop();
69    int ms = (int)(_timer.seconds() * 1000.0);
70    _timer.reset();
71    _timer.start();
72    if (ms >= PeriodicTask::max_interval) ms = PeriodicTask::max_interval - 1;
73    _intervalHistogram[ms]++;
74  }
75#endif
76  int orig_num_tasks = _num_tasks;
77  for(int index = 0; index < _num_tasks; index++) {
78    _tasks[index]->execute_if_pending(delay_time);
79    if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself
80      index--;  // re-do current slot as it has changed
81      orig_num_tasks = _num_tasks;
82    }
83  }
84}
85
86
87PeriodicTask::PeriodicTask(size_t interval_time) :
88  _counter(0), _interval(interval_time) {
89  // Sanity check the interval time
90  assert(_interval >= PeriodicTask::min_interval &&
91         _interval <= PeriodicTask::max_interval &&
92         _interval %  PeriodicTask::interval_gran == 0,
93              "improper PeriodicTask interval time");
94}
95
96PeriodicTask::~PeriodicTask() {
97  if (is_enrolled())
98    disenroll();
99}
100
101bool PeriodicTask::is_enrolled() const {
102  for(int index = 0; index < _num_tasks; index++)
103    if (_tasks[index] == this) return true;
104  return false;
105}
106
107void PeriodicTask::enroll() {
108  assert(WatcherThread::watcher_thread() == NULL, "dynamic enrollment of tasks not yet supported");
109
110  if (_num_tasks == PeriodicTask::max_tasks)
111    fatal("Overflow in PeriodicTask table");
112  _tasks[_num_tasks++] = this;
113}
114
115void PeriodicTask::disenroll() {
116  assert(WatcherThread::watcher_thread() == NULL ||
117         Thread::current() == WatcherThread::watcher_thread(),
118         "dynamic disenrollment currently only handled from WatcherThread from within task() method");
119
120  int index;
121  for(index = 0; index < _num_tasks && _tasks[index] != this; index++);
122  if (index == _num_tasks) return;
123  _num_tasks--;
124  for (; index < _num_tasks; index++) {
125    _tasks[index] = _tasks[index+1];
126  }
127}
128