1 /*
2 * Copyright (c) 1997, 2012, 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 *
37
38 class PeriodicTask: public CHeapObj<mtInternal> {
39 public:
40 // Useful constants.
41 // The interval constants are used to ensure the declared interval
42 // is appropriate; it must be between min_interval and max_interval,
43 // and have a granularity of interval_gran (all in millis).
44 enum { max_tasks = 10, // Max number of periodic tasks in system
45 interval_gran = 10,
46 min_interval = 10,
47 max_interval = 10000 };
48
49 static int num_tasks() { return _num_tasks; }
50
51 private:
52 int _counter;
53 const int _interval;
54
55 static int _num_tasks;
56 static PeriodicTask* _tasks[PeriodicTask::max_tasks];
57 static void real_time_tick(int delay_time);
58
59 #ifndef PRODUCT
60 static elapsedTimer _timer; // measures time between ticks
61 static int _ticks; // total number of ticks
62 static int _intervalHistogram[max_interval]; // to check spacing of timer interrupts
63 public:
64 static void print_intervals();
65 #endif
66 // Only the WatcherThread can cause us to execute PeriodicTasks
67 friend class WatcherThread;
68 public:
69 PeriodicTask(size_t interval_time); // interval is in milliseconds of elapsed time
70 ~PeriodicTask();
71
72 // Make the task active
73 // For dynamic enrollment at the time T, the task will execute somewhere
74 // between T and T + interval_time.
75 void enroll();
76
81 // make sure we don't overflow
82 jlong tmp = (jlong) _counter + (jlong) delay_time;
83
84 if (tmp >= (jlong) _interval) {
85 _counter = 0;
86 task();
87 } else {
88 _counter += delay_time;
89 }
90 }
91
92 // Returns how long (time in milliseconds) before the next time we should
93 // execute this task.
94 int time_to_next_interval() const {
95 assert(_interval > _counter, "task counter greater than interval?");
96 return _interval - _counter;
97 }
98
99 // Calculate when the next periodic task will fire.
100 // Called by the WatcherThread's run method.
101 static int time_to_wait();
102
103 // The task to perform at each period
104 virtual void task() = 0;
105 };
106
107 #endif // SHARE_VM_RUNTIME_TASK_HPP
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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 *
37
38 class PeriodicTask: public CHeapObj<mtInternal> {
39 public:
40 // Useful constants.
41 // The interval constants are used to ensure the declared interval
42 // is appropriate; it must be between min_interval and max_interval,
43 // and have a granularity of interval_gran (all in millis).
44 enum { max_tasks = 10, // Max number of periodic tasks in system
45 interval_gran = 10,
46 min_interval = 10,
47 max_interval = 10000 };
48
49 static int num_tasks() { return _num_tasks; }
50
51 private:
52 int _counter;
53 const int _interval;
54
55 static int _num_tasks;
56 static PeriodicTask* _tasks[PeriodicTask::max_tasks];
57 // Can only be called by the WatcherThread
58 static void real_time_tick(int delay_time);
59
60 #ifndef PRODUCT
61 static elapsedTimer _timer; // measures time between ticks
62 static int _ticks; // total number of ticks
63 static int _intervalHistogram[max_interval]; // to check spacing of timer interrupts
64 public:
65 static void print_intervals();
66 #endif
67 // Only the WatcherThread can cause us to execute PeriodicTasks
68 friend class WatcherThread;
69 public:
70 PeriodicTask(size_t interval_time); // interval is in milliseconds of elapsed time
71 ~PeriodicTask();
72
73 // Make the task active
74 // For dynamic enrollment at the time T, the task will execute somewhere
75 // between T and T + interval_time.
76 void enroll();
77
82 // make sure we don't overflow
83 jlong tmp = (jlong) _counter + (jlong) delay_time;
84
85 if (tmp >= (jlong) _interval) {
86 _counter = 0;
87 task();
88 } else {
89 _counter += delay_time;
90 }
91 }
92
93 // Returns how long (time in milliseconds) before the next time we should
94 // execute this task.
95 int time_to_next_interval() const {
96 assert(_interval > _counter, "task counter greater than interval?");
97 return _interval - _counter;
98 }
99
100 // Calculate when the next periodic task will fire.
101 // Called by the WatcherThread's run method.
102 // Requires the PeriodicTask_lock.
103 static int time_to_wait();
104
105 // The task to perform at each period
106 virtual void task() = 0;
107 };
108
109 #endif // SHARE_VM_RUNTIME_TASK_HPP
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