Mercurial > hg > graal-compiler
comparison src/share/vm/gc_implementation/g1/g1MMUTracker.cpp @ 342:37f87013dfd8
6711316: Open source the Garbage-First garbage collector
Summary: First mercurial integration of the code for the Garbage-First garbage collector.
Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
author | ysr |
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date | Thu, 05 Jun 2008 15:57:56 -0700 |
parents | |
children | e1fdf4fd34dc |
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189:0b27f3512f9e | 342:37f87013dfd8 |
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1 /* | |
2 * Copyright 2001-2007 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/_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), | |
40 _max_gc_time(max_gc_time), | |
41 _conc_overhead_time_sec(0.0) { } | |
42 | |
43 void | |
44 G1MMUTracker::update_conc_overhead(double conc_overhead) { | |
45 double conc_overhead_time_sec = _time_slice * conc_overhead; | |
46 if (conc_overhead_time_sec > 0.9 * _max_gc_time) { | |
47 // We are screwed, as we only seem to have <10% of the soft | |
48 // real-time goal available for pauses. Let's admit defeat and | |
49 // allow something more generous as a pause target. | |
50 conc_overhead_time_sec = 0.75 * _max_gc_time; | |
51 } | |
52 | |
53 _conc_overhead_time_sec = conc_overhead_time_sec; | |
54 } | |
55 | |
56 G1MMUTrackerQueue::G1MMUTrackerQueue(double time_slice, double max_gc_time) : | |
57 G1MMUTracker(time_slice, max_gc_time), | |
58 _head_index(0), | |
59 _tail_index(trim_index(_head_index+1)), | |
60 _no_entries(0) { } | |
61 | |
62 void G1MMUTrackerQueue::remove_expired_entries(double current_time) { | |
63 double limit = current_time - _time_slice; | |
64 while (_no_entries > 0) { | |
65 if (is_double_geq(limit, _array[_tail_index].end_time())) { | |
66 _tail_index = trim_index(_tail_index + 1); | |
67 --_no_entries; | |
68 } else | |
69 return; | |
70 } | |
71 guarantee(_no_entries == 0, "should have no entries in the array"); | |
72 } | |
73 | |
74 double G1MMUTrackerQueue::calculate_gc_time(double current_time) { | |
75 double gc_time = 0.0; | |
76 double limit = current_time - _time_slice; | |
77 for (int i = 0; i < _no_entries; ++i) { | |
78 int index = trim_index(_tail_index + i); | |
79 G1MMUTrackerQueueElem *elem = &_array[index]; | |
80 if (elem->end_time() > limit) { | |
81 if (elem->start_time() > limit) | |
82 gc_time += elem->duration(); | |
83 else | |
84 gc_time += elem->end_time() - limit; | |
85 } | |
86 } | |
87 return gc_time; | |
88 } | |
89 | |
90 void G1MMUTrackerQueue::add_pause(double start, double end, bool gc_thread) { | |
91 double longest_allowed = longest_pause_internal(start); | |
92 if (longest_allowed < 0.0) | |
93 longest_allowed = 0.0; | |
94 double duration = end - start; | |
95 | |
96 remove_expired_entries(end); | |
97 if (_no_entries == QueueLength) { | |
98 // OK, right now when we fill up we bomb out | |
99 // there are a few ways of dealing with this "gracefully" | |
100 // increase the array size (:-) | |
101 // remove the oldest entry (this might allow more GC time for | |
102 // the time slice than what's allowed) | |
103 // concolidate the two entries with the minimum gap between them | |
104 // (this mighte allow less GC time than what's allowed) | |
105 guarantee(0, "array full, currently we can't recover"); | |
106 } | |
107 _head_index = trim_index(_head_index + 1); | |
108 ++_no_entries; | |
109 _array[_head_index] = G1MMUTrackerQueueElem(start, end); | |
110 } | |
111 | |
112 // basically the _internal call does not remove expired entries | |
113 // this is for trying things out in the future and a couple | |
114 // of other places (debugging) | |
115 | |
116 double G1MMUTrackerQueue::longest_pause(double current_time) { | |
117 if (_DISABLE_MMU) | |
118 return _max_gc_time; | |
119 | |
120 MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag); | |
121 remove_expired_entries(current_time); | |
122 | |
123 return longest_pause_internal(current_time); | |
124 } | |
125 | |
126 double G1MMUTrackerQueue::longest_pause_internal(double current_time) { | |
127 double target_time = _max_gc_time; | |
128 | |
129 while( 1 ) { | |
130 double gc_time = | |
131 calculate_gc_time(current_time + target_time) + _conc_overhead_time_sec; | |
132 double diff = target_time + gc_time - _max_gc_time; | |
133 if (!is_double_leq_0(diff)) { | |
134 target_time -= diff; | |
135 if (is_double_leq_0(target_time)) { | |
136 target_time = -1.0; | |
137 break; | |
138 } | |
139 } else { | |
140 break; | |
141 } | |
142 } | |
143 | |
144 return target_time; | |
145 } | |
146 | |
147 // basically the _internal call does not remove expired entries | |
148 // this is for trying things out in the future and a couple | |
149 // of other places (debugging) | |
150 | |
151 double G1MMUTrackerQueue::when_sec(double current_time, double pause_time) { | |
152 if (_DISABLE_MMU) | |
153 return 0.0; | |
154 | |
155 MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag); | |
156 remove_expired_entries(current_time); | |
157 | |
158 return when_internal(current_time, pause_time); | |
159 } | |
160 | |
161 double G1MMUTrackerQueue::when_internal(double current_time, | |
162 double pause_time) { | |
163 // if the pause is over the maximum, just assume that it's the maximum | |
164 double adjusted_pause_time = | |
165 (pause_time > max_gc_time()) ? max_gc_time() : pause_time; | |
166 double earliest_end = current_time + adjusted_pause_time; | |
167 double limit = earliest_end - _time_slice; | |
168 double gc_time = calculate_gc_time(earliest_end); | |
169 double diff = gc_time + adjusted_pause_time - max_gc_time(); | |
170 if (is_double_leq_0(diff)) | |
171 return 0.0; | |
172 | |
173 int index = _tail_index; | |
174 while ( 1 ) { | |
175 G1MMUTrackerQueueElem *elem = &_array[index]; | |
176 if (elem->end_time() > limit) { | |
177 if (elem->start_time() > limit) | |
178 diff -= elem->duration(); | |
179 else | |
180 diff -= elem->end_time() - limit; | |
181 if (is_double_leq_0(diff)) | |
182 return elem->end_time() + diff + _time_slice - adjusted_pause_time - current_time; | |
183 } | |
184 index = trim_index(index+1); | |
185 guarantee(index != trim_index(_head_index + 1), "should not go past head"); | |
186 } | |
187 } |