1 /* 2 * Copyright (c) 1997, 2013, 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/thread.inline.hpp" 30 #include "runtime/timer.hpp" 31 #ifdef TARGET_OS_FAMILY_linux 32 # include "os_linux.inline.hpp" 33 #endif 34 #ifdef TARGET_OS_FAMILY_solaris 35 # include "os_solaris.inline.hpp" 36 #endif 37 #ifdef TARGET_OS_FAMILY_windows 38 # include "os_windows.inline.hpp" 39 #endif 40 #ifdef TARGET_OS_FAMILY_bsd 41 # include "os_bsd.inline.hpp" 42 #endif 43 44 int PeriodicTask::_num_tasks = 0; 45 PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks]; 46 #ifndef PRODUCT 47 elapsedTimer PeriodicTask::_timer; 48 int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval]; 49 int PeriodicTask::_ticks; 50 51 void PeriodicTask::print_intervals() { 52 if (ProfilerCheckIntervals) { 53 for (int i = 0; i < PeriodicTask::max_interval; i++) { 54 int n = _intervalHistogram[i]; 55 if (n > 0) tty->print_cr("%3d: %5d (%4.1f%%)", i, n, 100.0 * n / _ticks); 56 } 57 } 58 } 59 #endif 60 61 void PeriodicTask::real_time_tick(int delay_time) { 62 #ifndef PRODUCT 63 if (ProfilerCheckIntervals) { 64 _ticks++; 65 _timer.stop(); 66 int ms = (int)(_timer.seconds() * 1000.0); 67 _timer.reset(); 68 _timer.start(); 69 if (ms >= PeriodicTask::max_interval) ms = PeriodicTask::max_interval - 1; 70 _intervalHistogram[ms]++; 71 } 72 #endif 73 74 { 75 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 76 int orig_num_tasks = _num_tasks; 77 78 for(int index = 0; index < _num_tasks; index++) { 79 _tasks[index]->execute_if_pending(delay_time); 80 if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself 81 index--; // re-do current slot as it has changed 82 orig_num_tasks = _num_tasks; 83 } 84 } 85 } 86 } 87 88 int PeriodicTask::time_to_wait() { 89 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? 90 NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 91 92 if (_num_tasks == 0) { 93 return 0; // sleep until shutdown or a task is enrolled 94 } 95 96 int delay = _tasks[0]->time_to_next_interval(); 97 for (int index = 1; index < _num_tasks; index++) { 98 delay = MIN2(delay, _tasks[index]->time_to_next_interval()); 99 } 100 return delay; 101 } 102 103 104 PeriodicTask::PeriodicTask(size_t interval_time) : 105 _counter(0), _interval((int) interval_time) { 106 // Sanity check the interval time 107 assert(_interval >= PeriodicTask::min_interval && 108 _interval % PeriodicTask::interval_gran == 0, 109 "improper PeriodicTask interval time"); 110 } 111 112 PeriodicTask::~PeriodicTask() { 113 disenroll(); 114 } 115 116 /* enroll could be called from a JavaThread, so we have to check for 117 * safepoint when taking the lock to avoid deadlocking */ 118 void PeriodicTask::enroll() { 119 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? 120 NULL : PeriodicTask_lock); 121 122 if (_num_tasks == PeriodicTask::max_tasks) { 123 fatal("Overflow in PeriodicTask table"); 124 } 125 _tasks[_num_tasks++] = this; 126 127 WatcherThread* thread = WatcherThread::watcher_thread(); 128 if (thread) { 129 thread->unpark(); 130 } else { 131 WatcherThread::start(); 132 } 133 } 134 135 /* disenroll could be called from a JavaThread, so we have to check for 136 * safepoint when taking the lock to avoid deadlocking */ 137 void PeriodicTask::disenroll() { 138 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? 139 NULL : PeriodicTask_lock); 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 }