Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/g1MMUTracker.cpp @ 1286:ab75c83d7c37
Merge
author | johnc |
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date | Tue, 02 Mar 2010 13:57:46 -0800 |
parents | b81f3572f355 |
children | c18cbe5936b8 f16f1d7893de |
rev | line source |
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342 | 1 /* |
948 | 2 * Copyright 2001-2009 Sun Microsystems, Inc. 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 * | |
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/_g1MMUTracker.cpp.incl" | |
27 | |
28 #define _DISABLE_MMU 0 | |
29 | |
30 // can't rely on comparing doubles with tolerating a small margin for error | |
31 #define SMALL_MARGIN 0.0000001 | |
32 #define is_double_leq_0(_value) ( (_value) < SMALL_MARGIN ) | |
33 #define is_double_leq(_val1, _val2) is_double_leq_0((_val1) - (_val2)) | |
34 #define is_double_geq(_val1, _val2) is_double_leq_0((_val2) - (_val1)) | |
35 | |
36 /***** ALL TIMES ARE IN SECS!!!!!!! *****/ | |
37 | |
38 G1MMUTracker::G1MMUTracker(double time_slice, double max_gc_time) : | |
39 _time_slice(time_slice), | |
936 | 40 _max_gc_time(max_gc_time) { } |
342 | 41 |
42 G1MMUTrackerQueue::G1MMUTrackerQueue(double time_slice, double max_gc_time) : | |
43 G1MMUTracker(time_slice, max_gc_time), | |
44 _head_index(0), | |
45 _tail_index(trim_index(_head_index+1)), | |
46 _no_entries(0) { } | |
47 | |
48 void G1MMUTrackerQueue::remove_expired_entries(double current_time) { | |
49 double limit = current_time - _time_slice; | |
50 while (_no_entries > 0) { | |
51 if (is_double_geq(limit, _array[_tail_index].end_time())) { | |
52 _tail_index = trim_index(_tail_index + 1); | |
53 --_no_entries; | |
54 } else | |
55 return; | |
56 } | |
57 guarantee(_no_entries == 0, "should have no entries in the array"); | |
58 } | |
59 | |
60 double G1MMUTrackerQueue::calculate_gc_time(double current_time) { | |
61 double gc_time = 0.0; | |
62 double limit = current_time - _time_slice; | |
63 for (int i = 0; i < _no_entries; ++i) { | |
64 int index = trim_index(_tail_index + i); | |
65 G1MMUTrackerQueueElem *elem = &_array[index]; | |
66 if (elem->end_time() > limit) { | |
67 if (elem->start_time() > limit) | |
68 gc_time += elem->duration(); | |
69 else | |
70 gc_time += elem->end_time() - limit; | |
71 } | |
72 } | |
73 return gc_time; | |
74 } | |
75 | |
76 void G1MMUTrackerQueue::add_pause(double start, double end, bool gc_thread) { | |
77 double longest_allowed = longest_pause_internal(start); | |
78 if (longest_allowed < 0.0) | |
79 longest_allowed = 0.0; | |
80 double duration = end - start; | |
81 | |
82 remove_expired_entries(end); | |
83 if (_no_entries == QueueLength) { | |
84 // OK, right now when we fill up we bomb out | |
85 // there are a few ways of dealing with this "gracefully" | |
86 // increase the array size (:-) | |
87 // remove the oldest entry (this might allow more GC time for | |
88 // the time slice than what's allowed) | |
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89 // consolidate the two entries with the minimum gap between them |
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90 // (this might allow less GC time than what's allowed) |
1282 | 91 guarantee(NOT_PRODUCT(ScavengeALot ||) G1UseFixedWindowMMUTracker, |
92 "array full, currently we can't recover unless +G1UseFixedWindowMMUTracker"); | |
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93 // In the case where ScavengeALot is true, such overflow is not |
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94 // uncommon; in such cases, we can, without much loss of precision |
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95 // or performance (we are GC'ing most of the time anyway!), |
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96 // simply overwrite the oldest entry in the tracker: this |
1282 | 97 // is also the behaviour when G1UseFixedWindowMMUTracker is enabled. |
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98 _head_index = trim_index(_head_index + 1); |
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99 assert(_head_index == _tail_index, "Because we have a full circular buffer"); |
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100 _tail_index = trim_index(_tail_index + 1); |
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101 } else { |
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102 _head_index = trim_index(_head_index + 1); |
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103 ++_no_entries; |
342 | 104 } |
105 _array[_head_index] = G1MMUTrackerQueueElem(start, end); | |
106 } | |
107 | |
108 // basically the _internal call does not remove expired entries | |
109 // this is for trying things out in the future and a couple | |
110 // of other places (debugging) | |
111 | |
112 double G1MMUTrackerQueue::longest_pause(double current_time) { | |
113 if (_DISABLE_MMU) | |
114 return _max_gc_time; | |
115 | |
116 MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag); | |
117 remove_expired_entries(current_time); | |
118 | |
119 return longest_pause_internal(current_time); | |
120 } | |
121 | |
122 double G1MMUTrackerQueue::longest_pause_internal(double current_time) { | |
123 double target_time = _max_gc_time; | |
124 | |
125 while( 1 ) { | |
126 double gc_time = | |
936 | 127 calculate_gc_time(current_time + target_time); |
342 | 128 double diff = target_time + gc_time - _max_gc_time; |
129 if (!is_double_leq_0(diff)) { | |
130 target_time -= diff; | |
131 if (is_double_leq_0(target_time)) { | |
132 target_time = -1.0; | |
133 break; | |
134 } | |
135 } else { | |
136 break; | |
137 } | |
138 } | |
139 | |
140 return target_time; | |
141 } | |
142 | |
143 // basically the _internal call does not remove expired entries | |
144 // this is for trying things out in the future and a couple | |
145 // of other places (debugging) | |
146 | |
147 double G1MMUTrackerQueue::when_sec(double current_time, double pause_time) { | |
148 if (_DISABLE_MMU) | |
149 return 0.0; | |
150 | |
151 MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag); | |
152 remove_expired_entries(current_time); | |
153 | |
154 return when_internal(current_time, pause_time); | |
155 } | |
156 | |
157 double G1MMUTrackerQueue::when_internal(double current_time, | |
158 double pause_time) { | |
159 // if the pause is over the maximum, just assume that it's the maximum | |
160 double adjusted_pause_time = | |
161 (pause_time > max_gc_time()) ? max_gc_time() : pause_time; | |
162 double earliest_end = current_time + adjusted_pause_time; | |
163 double limit = earliest_end - _time_slice; | |
164 double gc_time = calculate_gc_time(earliest_end); | |
165 double diff = gc_time + adjusted_pause_time - max_gc_time(); | |
166 if (is_double_leq_0(diff)) | |
167 return 0.0; | |
168 | |
169 int index = _tail_index; | |
170 while ( 1 ) { | |
171 G1MMUTrackerQueueElem *elem = &_array[index]; | |
172 if (elem->end_time() > limit) { | |
173 if (elem->start_time() > limit) | |
174 diff -= elem->duration(); | |
175 else | |
176 diff -= elem->end_time() - limit; | |
177 if (is_double_leq_0(diff)) | |
178 return elem->end_time() + diff + _time_slice - adjusted_pause_time - current_time; | |
179 } | |
180 index = trim_index(index+1); | |
181 guarantee(index != trim_index(_head_index + 1), "should not go past head"); | |
182 } | |
183 } |