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annotate src/share/vm/runtime/task.hpp @ 1972:f95d63e2154a
6989984: Use standard include model for Hospot
Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg
| author | stefank |
|---|---|
| date | Tue, 23 Nov 2010 13:22:55 -0800 |
| parents | c18cbe5936b8 |
| children | d2a62e0f25eb |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 1972 | 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #ifndef SHARE_VM_RUNTIME_TASK_HPP |
| 26 #define SHARE_VM_RUNTIME_TASK_HPP | |
| 27 | |
| 28 #include "utilities/top.hpp" | |
| 29 | |
| 0 | 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(); | |
| 37 | |
| 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 }; | |
| 48 | |
| 49 static int num_tasks() { return _num_tasks; } | |
| 50 | |
| 51 private: | |
| 52 size_t _counter; | |
| 53 const size_t _interval; | |
| 54 | |
| 55 static int _num_tasks; | |
| 56 static PeriodicTask* _tasks[PeriodicTask::max_tasks]; | |
| 57 static void real_time_tick(size_t 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 // Tells whether is enrolled | |
| 73 bool is_enrolled() const; | |
| 74 | |
| 75 // Make the task active | |
| 76 // NOTE: this may only be called before the WatcherThread has been started | |
| 77 void enroll(); | |
| 78 | |
| 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(); | |
| 84 | |
| 85 void execute_if_pending(size_t delay_time) { | |
| 86 _counter += delay_time; | |
| 87 if (_counter >= _interval) { | |
| 88 _counter = 0; | |
| 89 task(); | |
| 90 } | |
| 91 } | |
| 92 | |
| 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 } | |
| 99 | |
| 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 } | |
| 110 | |
| 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 } | |
| 117 | |
| 118 // The task to perform at each period | |
| 119 virtual void task() = 0; | |
| 120 }; | |
| 1972 | 121 |
| 122 #endif // SHARE_VM_RUNTIME_TASK_HPP |