src/share/vm/gc_implementation/g1/g1MMUTracker.hpp

Mon, 09 Mar 2009 13:28:46 -0700

author
xdono
date
Mon, 09 Mar 2009 13:28:46 -0700
changeset 1014
0fbdb4381b99
parent 984
fe3d7c11b4b7
child 1371
e1fdf4fd34dc
permissions
-rw-r--r--

6814575: Update copyright year
Summary: Update copyright for files that have been modified in 2009, up to 03/09
Reviewed-by: katleman, tbell, ohair

     1 /*
     2  * Copyright 2001-2009 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  */
    25 // Keeps track of the GC work and decides when it is OK to do GC work
    26 // and for how long so that the MMU invariants are maintained.
    28 /***** ALL TIMES ARE IN SECS!!!!!!! *****/
    30 // this is the "interface"
    31 class G1MMUTracker: public CHeapObj {
    32 protected:
    33   double          _time_slice;
    34   double          _max_gc_time; // this is per time slice
    36   double          _conc_overhead_time_sec;
    38 public:
    39   G1MMUTracker(double time_slice, double max_gc_time);
    41   void update_conc_overhead(double conc_overhead);
    43   virtual void add_pause(double start, double end, bool gc_thread) = 0;
    44   virtual double longest_pause(double current_time) = 0;
    45   virtual double when_sec(double current_time, double pause_time) = 0;
    47   double max_gc_time() {
    48     return _max_gc_time - _conc_overhead_time_sec;
    49   }
    51   inline bool now_max_gc(double current_time) {
    52     return when_sec(current_time, max_gc_time()) < 0.00001;
    53   }
    55   inline double when_max_gc_sec(double current_time) {
    56     return when_sec(current_time, max_gc_time());
    57   }
    59   inline jlong when_max_gc_ms(double current_time) {
    60     double when = when_max_gc_sec(current_time);
    61     return (jlong) (when * 1000.0);
    62   }
    64   inline jlong when_ms(double current_time, double pause_time) {
    65     double when = when_sec(current_time, pause_time);
    66     return (jlong) (when * 1000.0);
    67   }
    68 };
    70 class G1MMUTrackerQueueElem VALUE_OBJ_CLASS_SPEC {
    71 private:
    72   double _start_time;
    73   double _end_time;
    75 public:
    76   inline double start_time() { return _start_time; }
    77   inline double end_time()   { return _end_time; }
    78   inline double duration()   { return _end_time - _start_time; }
    80   G1MMUTrackerQueueElem() {
    81     _start_time = 0.0;
    82     _end_time   = 0.0;
    83   }
    85   G1MMUTrackerQueueElem(double start_time, double end_time) {
    86     _start_time = start_time;
    87     _end_time   = end_time;
    88   }
    89 };
    91 // this is an implementation of the MMUTracker using a (fixed-size) queue
    92 // that keeps track of all the recent pause times
    93 class G1MMUTrackerQueue: public G1MMUTracker {
    94 private:
    95   enum PrivateConstants {
    96     QueueLength = 64
    97   };
    99   // The array keeps track of all the pauses that fall within a time
   100   // slice (the last time slice during which pauses took place).
   101   // The data structure implemented is a circular queue.
   102   // Head "points" to the most recent addition, tail to the oldest one.
   103   // The array is of fixed size and I don't think we'll need more than
   104   // two or three entries with the current behaviour of G1 pauses.
   105   // If the array is full, an easy fix is to look for the pauses with
   106   // the shortest gap between them and concolidate them.
   108   G1MMUTrackerQueueElem _array[QueueLength];
   109   int                   _head_index;
   110   int                   _tail_index;
   111   int                   _no_entries;
   113   inline int trim_index(int index) {
   114     return (index + QueueLength) % QueueLength;
   115   }
   117   void remove_expired_entries(double current_time);
   118   double calculate_gc_time(double current_time);
   120   double longest_pause_internal(double current_time);
   121   double when_internal(double current_time, double pause_time);
   123 public:
   124   G1MMUTrackerQueue(double time_slice, double max_gc_time);
   126   virtual void add_pause(double start, double end, bool gc_thread);
   128   virtual double longest_pause(double current_time);
   129   virtual double when_sec(double current_time, double pause_time);
   130 };

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