1 /*

     2  * Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 # include "incls/_precompiled.incl"

    26 # include "incls/_task.cpp.incl"

    27 

    28 int PeriodicTask::_num_tasks = 0;

    29 PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks];

    30 #ifndef PRODUCT

    31 elapsedTimer PeriodicTask::_timer;

    32 int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval];

    33 int PeriodicTask::_ticks;

    34 

    35 void PeriodicTask::print_intervals() {

    36   if (ProfilerCheckIntervals) {

    37     for (int i = 0; i < PeriodicTask::max_interval; i++) {

    38       int n = _intervalHistogram[i];

    39       if (n > 0) tty->print_cr("%3d: %5d (%4.1f%%)", i, n, 100.0 * n / _ticks);

    40     }

    41   }

    42 }

    43 #endif

    44 

    45 void PeriodicTask::real_time_tick(size_t delay_time) {

    46 #ifndef PRODUCT

    47   if (ProfilerCheckIntervals) {

    48     _ticks++;

    49     _timer.stop();

    50     int ms = (int)(_timer.seconds() * 1000.0);

    51     _timer.reset();

    52     _timer.start();

    53     if (ms >= PeriodicTask::max_interval) ms = PeriodicTask::max_interval - 1;

    54     _intervalHistogram[ms]++;

    55   }

    56 #endif

    57   int orig_num_tasks = _num_tasks;

    58   for(int index = 0; index < _num_tasks; index++) {

    59     _tasks[index]->execute_if_pending(delay_time);

    60     if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself

    61       index--;  // re-do current slot as it has changed

    62       orig_num_tasks = _num_tasks;

    63     }

    64   }

    65 }

    66 

    67 

    68 PeriodicTask::PeriodicTask(size_t interval_time) :

    69   _counter(0), _interval(interval_time) {

    70   assert(is_init_completed(), "Periodic tasks should not start during VM initialization");

    71   // Sanity check the interval time

    72   assert(_interval >= PeriodicTask::min_interval &&

    73          _interval <= PeriodicTask::max_interval &&

    74          _interval %  PeriodicTask::interval_gran == 0,

    75               "improper PeriodicTask interval time");

    76 }

    77 

    78 PeriodicTask::~PeriodicTask() {

    79   if (is_enrolled())

    80     disenroll();

    81 }

    82 

    83 bool PeriodicTask::is_enrolled() const {

    84   for(int index = 0; index < _num_tasks; index++)

    85     if (_tasks[index] == this) return true;

    86   return false;

    87 }

    88 

    89 void PeriodicTask::enroll() {

    90   assert(WatcherThread::watcher_thread() == NULL, "dynamic enrollment of tasks not yet supported");

    91 

    92   if (_num_tasks == PeriodicTask::max_tasks)

    93     fatal("Overflow in PeriodicTask table");

    94   _tasks[_num_tasks++] = this;

    95 }

    96 

    97 void PeriodicTask::disenroll() {

    98   assert(WatcherThread::watcher_thread() == NULL ||

    99          Thread::current() == WatcherThread::watcher_thread(),

   100          "dynamic disenrollment currently only handled from WatcherThread from within task() method");

   101 

   102   int index;

   103   for(index = 0; index < _num_tasks && _tasks[index] != this; index++);

   104   if (index == _num_tasks) return;

   105   _num_tasks--;

   106   for (; index < _num_tasks; index++) {

   107     _tasks[index] = _tasks[index+1];

   108   }

   109 }

   110 

   111 TimeMillisUpdateTask* TimeMillisUpdateTask::_task = NULL;

   112 

   113 void TimeMillisUpdateTask::task() {

   114   os::update_global_time();

   115 }

   116 

   117 void TimeMillisUpdateTask::engage() {

   118   assert(_task == NULL, "init twice?");

   119   os::update_global_time(); // initial update

   120   os::enable_global_time();

   121   _task = new TimeMillisUpdateTask(CacheTimeMillisGranularity);

   122   _task->enroll();

   123 }

   124 

   125 void TimeMillisUpdateTask::disengage() {

   126   assert(_task != NULL, "uninit twice?");

   127   os::disable_global_time();

   128   _task->disenroll();

   129   delete _task;

   130   _task = NULL;

   131 }