Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/g1MMUTracker.hpp @ 3759:cfcf2ba8f3eb
Merge
author | never |
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date | Wed, 15 Jun 2011 10:20:03 -0700 |
parents | f95d63e2154a |
children | d2a62e0f25eb |
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342 | 1 /* |
1972 | 2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. |
342 | 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. |
342 | 22 * |
23 */ | |
24 | |
1972 | 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1MMUTRACKER_HPP |
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1MMUTRACKER_HPP | |
27 | |
28 #include "memory/allocation.hpp" | |
29 #include "utilities/debug.hpp" | |
30 | |
342 | 31 // Keeps track of the GC work and decides when it is OK to do GC work |
32 // and for how long so that the MMU invariants are maintained. | |
33 | |
34 /***** ALL TIMES ARE IN SECS!!!!!!! *****/ | |
35 | |
36 // this is the "interface" | |
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37 class G1MMUTracker: public CHeapObj { |
342 | 38 protected: |
39 double _time_slice; | |
40 double _max_gc_time; // this is per time slice | |
41 | |
42 public: | |
43 G1MMUTracker(double time_slice, double max_gc_time); | |
44 | |
45 virtual void add_pause(double start, double end, bool gc_thread) = 0; | |
46 virtual double longest_pause(double current_time) = 0; | |
47 virtual double when_sec(double current_time, double pause_time) = 0; | |
48 | |
49 double max_gc_time() { | |
936 | 50 return _max_gc_time; |
342 | 51 } |
52 | |
53 inline bool now_max_gc(double current_time) { | |
54 return when_sec(current_time, max_gc_time()) < 0.00001; | |
55 } | |
56 | |
57 inline double when_max_gc_sec(double current_time) { | |
58 return when_sec(current_time, max_gc_time()); | |
59 } | |
60 | |
61 inline jlong when_max_gc_ms(double current_time) { | |
62 double when = when_max_gc_sec(current_time); | |
63 return (jlong) (when * 1000.0); | |
64 } | |
65 | |
66 inline jlong when_ms(double current_time, double pause_time) { | |
67 double when = when_sec(current_time, pause_time); | |
68 return (jlong) (when * 1000.0); | |
69 } | |
70 }; | |
71 | |
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72 class G1MMUTrackerQueueElem VALUE_OBJ_CLASS_SPEC { |
342 | 73 private: |
74 double _start_time; | |
75 double _end_time; | |
76 | |
77 public: | |
78 inline double start_time() { return _start_time; } | |
79 inline double end_time() { return _end_time; } | |
80 inline double duration() { return _end_time - _start_time; } | |
81 | |
82 G1MMUTrackerQueueElem() { | |
83 _start_time = 0.0; | |
84 _end_time = 0.0; | |
85 } | |
86 | |
87 G1MMUTrackerQueueElem(double start_time, double end_time) { | |
88 _start_time = start_time; | |
89 _end_time = end_time; | |
90 } | |
91 }; | |
92 | |
93 // this is an implementation of the MMUTracker using a (fixed-size) queue | |
94 // that keeps track of all the recent pause times | |
95 class G1MMUTrackerQueue: public G1MMUTracker { | |
96 private: | |
97 enum PrivateConstants { | |
98 QueueLength = 64 | |
99 }; | |
100 | |
101 // The array keeps track of all the pauses that fall within a time | |
102 // slice (the last time slice during which pauses took place). | |
103 // The data structure implemented is a circular queue. | |
104 // Head "points" to the most recent addition, tail to the oldest one. | |
105 // The array is of fixed size and I don't think we'll need more than | |
106 // two or three entries with the current behaviour of G1 pauses. | |
107 // If the array is full, an easy fix is to look for the pauses with | |
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108 // the shortest gap between them and consolidate them. |
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109 // For now, we have taken the expedient alternative of forgetting |
1282 | 110 // the oldest entry in the event that +G1UseFixedWindowMMUTracker, thus |
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111 // potentially violating MMU specs for some time thereafter. |
342 | 112 |
113 G1MMUTrackerQueueElem _array[QueueLength]; | |
114 int _head_index; | |
115 int _tail_index; | |
116 int _no_entries; | |
117 | |
118 inline int trim_index(int index) { | |
119 return (index + QueueLength) % QueueLength; | |
120 } | |
121 | |
122 void remove_expired_entries(double current_time); | |
123 double calculate_gc_time(double current_time); | |
124 | |
125 double longest_pause_internal(double current_time); | |
126 double when_internal(double current_time, double pause_time); | |
127 | |
128 public: | |
129 G1MMUTrackerQueue(double time_slice, double max_gc_time); | |
130 | |
131 virtual void add_pause(double start, double end, bool gc_thread); | |
132 | |
133 virtual double longest_pause(double current_time); | |
134 virtual double when_sec(double current_time, double pause_time); | |
135 }; | |
1972 | 136 |
137 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1MMUTRACKER_HPP |