1 /*
2 * Copyright (c) 1997, 2014, 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 *
30 #include "runtime/timer.hpp"
31
32 int PeriodicTask::_num_tasks = 0;
33 PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks];
34 #ifndef PRODUCT
35 elapsedTimer PeriodicTask::_timer;
36 int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval];
37 int PeriodicTask::_ticks;
38
39 void PeriodicTask::print_intervals() {
40 if (ProfilerCheckIntervals) {
41 for (int i = 0; i < PeriodicTask::max_interval; i++) {
42 int n = _intervalHistogram[i];
43 if (n > 0) tty->print_cr("%3d: %5d (%4.1f%%)", i, n, 100.0 * n / _ticks);
44 }
45 }
46 }
47 #endif
48
49 void PeriodicTask::real_time_tick(int delay_time) {
50 #ifndef PRODUCT
51 if (ProfilerCheckIntervals) {
52 _ticks++;
53 _timer.stop();
54 int ms = (int)(_timer.seconds() * 1000.0);
55 _timer.reset();
56 _timer.start();
57 if (ms >= PeriodicTask::max_interval) ms = PeriodicTask::max_interval - 1;
58 _intervalHistogram[ms]++;
59 }
60 #endif
61
62 {
63 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
64 int orig_num_tasks = _num_tasks;
65
66 for(int index = 0; index < _num_tasks; index++) {
67 _tasks[index]->execute_if_pending(delay_time);
68 if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself
69 index--; // re-do current slot as it has changed
70 orig_num_tasks = _num_tasks;
71 }
72 }
73 }
74 }
75
76 int PeriodicTask::time_to_wait() {
77 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
78 NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
79
80 if (_num_tasks == 0) {
81 return 0; // sleep until shutdown or a task is enrolled
82 }
83
84 int delay = _tasks[0]->time_to_next_interval();
85 for (int index = 1; index < _num_tasks; index++) {
86 delay = MIN2(delay, _tasks[index]->time_to_next_interval());
87 }
88 return delay;
89 }
90
91
92 PeriodicTask::PeriodicTask(size_t interval_time) :
93 _counter(0), _interval((int) interval_time) {
94 // Sanity check the interval time
95 assert(_interval >= PeriodicTask::min_interval &&
96 _interval % PeriodicTask::interval_gran == 0,
97 "improper PeriodicTask interval time");
98 }
99
100 PeriodicTask::~PeriodicTask() {
101 disenroll();
102 }
103
104 /* enroll could be called from a JavaThread, so we have to check for
105 * safepoint when taking the lock to avoid deadlocking */
106 void PeriodicTask::enroll() {
107 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
108 NULL : PeriodicTask_lock);
109
110 if (_num_tasks == PeriodicTask::max_tasks) {
111 fatal("Overflow in PeriodicTask table");
112 }
113 _tasks[_num_tasks++] = this;
114
115 WatcherThread* thread = WatcherThread::watcher_thread();
116 if (thread) {
117 thread->unpark();
118 } else {
119 WatcherThread::start();
120 }
121 }
122
123 /* disenroll could be called from a JavaThread, so we have to check for
124 * safepoint when taking the lock to avoid deadlocking */
125 void PeriodicTask::disenroll() {
126 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
127 NULL : PeriodicTask_lock);
128
129 int index;
130 for(index = 0; index < _num_tasks && _tasks[index] != this; index++)
131 ;
132
133 if (index == _num_tasks) {
134 return;
135 }
136
137 _num_tasks--;
138
139 for (; index < _num_tasks; index++) {
140 _tasks[index] = _tasks[index+1];
141 }
142 }
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1 /*
2 * Copyright (c) 1997, 2015, 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 *
30 #include "runtime/timer.hpp"
31
32 int PeriodicTask::_num_tasks = 0;
33 PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks];
34 #ifndef PRODUCT
35 elapsedTimer PeriodicTask::_timer;
36 int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval];
37 int PeriodicTask::_ticks;
38
39 void PeriodicTask::print_intervals() {
40 if (ProfilerCheckIntervals) {
41 for (int i = 0; i < PeriodicTask::max_interval; i++) {
42 int n = _intervalHistogram[i];
43 if (n > 0) tty->print_cr("%3d: %5d (%4.1f%%)", i, n, 100.0 * n / _ticks);
44 }
45 }
46 }
47 #endif
48
49 void PeriodicTask::real_time_tick(int delay_time) {
50 assert(Thread::current()->is_Watcher_thread(), "must be WatcherThread");
51
52 #ifndef PRODUCT
53 if (ProfilerCheckIntervals) {
54 _ticks++;
55 _timer.stop();
56 int ms = (int)(_timer.seconds() * 1000.0);
57 _timer.reset();
58 _timer.start();
59 if (ms >= PeriodicTask::max_interval) ms = PeriodicTask::max_interval - 1;
60 _intervalHistogram[ms]++;
61 }
62 #endif
63
64 {
65 // The WatcherThread does not honor the safepoint protocol for
66 // PeriodicTask_lock in order to provide more consistent task
67 // execution timing.
68 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
69 int orig_num_tasks = _num_tasks;
70
71 for(int index = 0; index < _num_tasks; index++) {
72 _tasks[index]->execute_if_pending(delay_time);
73 if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself
74 index--; // re-do current slot as it has changed
75 orig_num_tasks = _num_tasks;
76 }
77 }
78 }
79 }
80
81 int PeriodicTask::time_to_wait() {
82 assert(Thread::current()->is_Watcher_thread(), "must be WatcherThread");
83 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
84
85 if (_num_tasks == 0) {
86 return 0; // sleep until shutdown or a task is enrolled
87 }
88
89 int delay = _tasks[0]->time_to_next_interval();
90 for (int index = 1; index < _num_tasks; index++) {
91 delay = MIN2(delay, _tasks[index]->time_to_next_interval());
92 }
93 return delay;
94 }
95
96
97 PeriodicTask::PeriodicTask(size_t interval_time) :
98 _counter(0), _interval((int) interval_time) {
99 // Sanity check the interval time
100 assert(_interval >= PeriodicTask::min_interval &&
101 _interval % PeriodicTask::interval_gran == 0,
102 "improper PeriodicTask interval time");
103 }
104
105 PeriodicTask::~PeriodicTask() {
106 // This PeriodicTask may have already been disenrolled by a
107 // subclass with a non-trivial destructor.
108 disenroll();
109 }
110
111 // enroll the current PeriodicTask
112 void PeriodicTask::enroll() {
113 // Follow normal safepoint aware lock enter protocol if the caller does
114 // not already own the PeriodicTask_lock. Otherwise, we don't try to
115 // enter it again to avoid deadlocking with a safepoint that started
116 // after the initial enter and before this enter.
117 //
118 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL
119 : PeriodicTask_lock);
120
121 if (_num_tasks == PeriodicTask::max_tasks) {
122 fatal("Overflow in PeriodicTask table");
123 }
124 _tasks[_num_tasks++] = this;
125
126 WatcherThread* thread = WatcherThread::watcher_thread();
127 if (thread != NULL) {
128 thread->unpark();
129 } else {
130 WatcherThread::start();
131 }
132 }
133
134 // disenroll the current PeriodicTask
135 void PeriodicTask::disenroll() {
136 // Follow normal safepoint aware lock enter protocol if the caller does
137 // not already own the PeriodicTask_lock. Otherwise, we don't try to
138 // enter it again to avoid deadlocking with a safepoint that started
139 // after the initial enter and before this enter.
140 //
141 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL
142 : PeriodicTask_lock);
143
144 int index;
145 for(index = 0; index < _num_tasks && _tasks[index] != this; index++)
146 ;
147
148 if (index == _num_tasks) {
149 return;
150 }
151
152 _num_tasks--;
153
154 for (; index < _num_tasks; index++) {
155 _tasks[index] = _tasks[index+1];
156 }
157 }
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