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.
22 *
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
47 int PeriodicTask::_num_tasks = 0;
48 PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks];
49 #ifndef PRODUCT
50 elapsedTimer PeriodicTask::_timer;
51 int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval];
52 int PeriodicTask::_ticks;
53
54 void 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
64 void PeriodicTask::real_time_tick(int 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
77 {
78 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
79 int orig_num_tasks = _num_tasks;
80
81 for(int index = 0; index < _num_tasks; index++) {
82 _tasks[index]->execute_if_pending(delay_time);
83 if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself
84 index--; // re-do current slot as it has changed
85 orig_num_tasks = _num_tasks;
86 }
87 }
88 }
89 }
90
91 int PeriodicTask::time_to_wait() {
92 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
93 NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
94
95 if (_num_tasks == 0) {
96 return 0; // sleep until shutdown or a task is enrolled
97 }
98
99 int delay = _tasks[0]->time_to_next_interval();
100 for (int index = 1; index < _num_tasks; index++) {
101 delay = MIN2(delay, _tasks[index]->time_to_next_interval());
102 }
103 return delay;
104 }
105
106
107 PeriodicTask::PeriodicTask(size_t interval_time) :
108 _counter(0), _interval((int) interval_time) {
109 // Sanity check the interval time
110 assert(_interval >= PeriodicTask::min_interval &&
111 _interval <= PeriodicTask::max_interval &&
112 _interval % PeriodicTask::interval_gran == 0,
113 "improper PeriodicTask interval time");
114 }
115
116 PeriodicTask::~PeriodicTask() {
117 disenroll();
118 }
119
120 void PeriodicTask::enroll() {
121 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
122 NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
123
124 if (_num_tasks == PeriodicTask::max_tasks) {
125 fatal("Overflow in PeriodicTask table");
126 }
127 _tasks[_num_tasks++] = this;
128
129 WatcherThread* thread = WatcherThread::watcher_thread();
130 if (thread) {
131 thread->unpark();
132 } else {
133 WatcherThread::start();
134 }
135 }
136
137 void PeriodicTask::disenroll() {
138 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
139 NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
140
141 int index;
142 for(index = 0; index < _num_tasks && _tasks[index] != this; index++)
143 ;
144
145 if (index == _num_tasks) {
146 return;
147 }
148
149 _num_tasks--;
150
151 for (; index < _num_tasks; index++) {
152 _tasks[index] = _tasks[index+1];
153 }
154 }