Mon, 18 Jun 2012 12:29:21 -0700
7176856: add the JRE name to the error log
Reviewed-by: coleenp, jrose, kvn, twisti
Contributed-by: Krystal Mok <sajia@taobao.com>
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 */
25 #ifndef SHARE_VM_RUNTIME_TASK_HPP
26 #define SHARE_VM_RUNTIME_TASK_HPP
28 #include "utilities/top.hpp"
30 // A PeriodicTask has the sole purpose of executing its task
31 // function with regular intervals.
32 // Usage:
33 // PeriodicTask pf(10);
34 // pf.enroll();
35 // ...
36 // pf.disenroll();
38 class PeriodicTask: public CHeapObj {
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 };
49 static int num_tasks() { return _num_tasks; }
51 private:
52 size_t _counter;
53 const size_t _interval;
55 static int _num_tasks;
56 static PeriodicTask* _tasks[PeriodicTask::max_tasks];
57 static void real_time_tick(size_t delay_time);
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();
72 // Tells whether is enrolled
73 bool is_enrolled() const;
75 // Make the task active
76 // NOTE: this may only be called before the WatcherThread has been started
77 void enroll();
79 // Make the task deactive
80 // NOTE: this may only be called either while the WatcherThread is
81 // inactive or by a task from within its task() method. One-shot or
82 // several-shot tasks may be implemented this way.
83 void disenroll();
85 void execute_if_pending(size_t delay_time) {
86 _counter += delay_time;
87 if (_counter >= _interval) {
88 _counter = 0;
89 task();
90 }
91 }
93 // Returns how long (time in milliseconds) before the next time we should
94 // execute this task.
95 size_t time_to_next_interval() const {
96 assert(_interval > _counter, "task counter greater than interval?");
97 return _interval - _counter;
98 }
100 // Calculate when the next periodic task will fire.
101 // Called by the WatcherThread's run method.
102 // This assumes that periodic tasks aren't entering the system
103 // dynamically, except for during startup.
104 static size_t time_to_wait() {
105 if (_num_tasks == 0) {
106 // Don't wait any more; shut down the thread since we don't
107 // currently support dynamic enrollment.
108 return 0;
109 }
111 size_t delay = _tasks[0]->time_to_next_interval();
112 for (int index = 1; index < _num_tasks; index++) {
113 delay = MIN2(delay, _tasks[index]->time_to_next_interval());
114 }
115 return delay;
116 }
118 // The task to perform at each period
119 virtual void task() = 0;
120 };
122 #endif // SHARE_VM_RUNTIME_TASK_HPP