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  */
  24 
  25 #include "precompiled.hpp"
  26 #include "memory/allocation.hpp"
  27 #include "runtime/init.hpp"
  28 #include "runtime/task.hpp"
  29 #include "runtime/timer.hpp"
  30 #ifdef TARGET_OS_FAMILY_linux
  31 # include "os_linux.inline.hpp"
  32 # include "thread_linux.inline.hpp"
  33 #endif
  34 #ifdef TARGET_OS_FAMILY_solaris
  35 # include "os_solaris.inline.hpp"
  36 # include "thread_solaris.inline.hpp"
  37 #endif
  38 #ifdef TARGET_OS_FAMILY_windows
  39 # include "os_windows.inline.hpp"
  40 # include "thread_windows.inline.hpp"
  41 #endif
  42 #ifdef TARGET_OS_FAMILY_bsd
  43 # include "os_bsd.inline.hpp"
  44 # include "thread_bsd.inline.hpp"
  45 #endif
  46 
  47 int PeriodicTask::_num_tasks = 0;
  48 PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks];
  49 #ifndef PRODUCT
  50 elapsedTimer PeriodicTask::_timer;
  51 int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval];
  52 int PeriodicTask::_ticks;
  53 
  54 void PeriodicTask::print_intervals() {
  55   if (ProfilerCheckIntervals) {
  56     for (int i = 0; i < PeriodicTask::max_interval; i++) {
  57       int n = _intervalHistogram[i];
  58       if (n > 0) tty->print_cr("%3d: %5d (%4.1f%%)", i, n, 100.0 * n / _ticks);
  59     }
  60   }
  61 }
  62 #endif
  63 
  64 void PeriodicTask::real_time_tick(size_t delay_time) {
  65 #ifndef PRODUCT
  66   if (ProfilerCheckIntervals) {
  67     _ticks++;
  68     _timer.stop();
  69     int ms = (int)(_timer.seconds() * 1000.0);
  70     _timer.reset();
  71     _timer.start();
  72     if (ms >= PeriodicTask::max_interval) ms = PeriodicTask::max_interval - 1;
  73     _intervalHistogram[ms]++;
  74   }
  75 #endif
  76   int orig_num_tasks = _num_tasks;
  77   for(int index = 0; index < _num_tasks; index++) {
  78     _tasks[index]->execute_if_pending(delay_time);
  79     if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself
  80       index--;  // re-do current slot as it has changed
  81       orig_num_tasks = _num_tasks;
  82     }
  83   }
  84 }
  85 
  86 
  87 PeriodicTask::PeriodicTask(size_t interval_time) :
  88   _counter(0), _interval(interval_time) {
  89   // Sanity check the interval time
  90   assert(_interval >= PeriodicTask::min_interval &&
  91          _interval <= PeriodicTask::max_interval &&
  92          _interval %  PeriodicTask::interval_gran == 0,
  93               "improper PeriodicTask interval time");
  94 }
  95 
  96 PeriodicTask::~PeriodicTask() {
  97   if (is_enrolled())
  98     disenroll();
  99 }
 100 
 101 bool PeriodicTask::is_enrolled() const {
 102   for(int index = 0; index < _num_tasks; index++)
 103     if (_tasks[index] == this) return true;
 104   return false;
 105 }
 106 
 107 void PeriodicTask::enroll() {
 108   assert(WatcherThread::watcher_thread() == NULL, "dynamic enrollment of tasks not yet supported");
 109 
 110   if (_num_tasks == PeriodicTask::max_tasks)
 111     fatal("Overflow in PeriodicTask table");
 112   _tasks[_num_tasks++] = this;
 113 }
 114 
 115 void PeriodicTask::disenroll() {
 116   assert(WatcherThread::watcher_thread() == NULL ||
 117          Thread::current() == WatcherThread::watcher_thread(),
 118          "dynamic disenrollment currently only handled from WatcherThread from within task() method");
 119 
 120   int index;
 121   for(index = 0; index < _num_tasks && _tasks[index] != this; index++);
 122   if (index == _num_tasks) return;
 123   _num_tasks--;
 124   for (; index < _num_tasks; index++) {
 125     _tasks[index] = _tasks[index+1];
 126   }
 127 }