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G1: Use SoftMaxHeapSize to guide GC heuristics
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--- old/src/hotspot/share/gc/g1/g1IHOPControl.cpp
+++ new/src/hotspot/share/gc/g1/g1IHOPControl.cpp
1 1 /*
2 2 * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
3 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 4 *
5 5 * This code is free software; you can redistribute it and/or modify it
6 6 * under the terms of the GNU General Public License version 2 only, as
7 7 * published by the Free Software Foundation.
8 8 *
9 9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 12 * version 2 for more details (a copy is included in the LICENSE file that
13 13 * accompanied this code).
14 14 *
15 15 * You should have received a copy of the GNU General Public License version
16 16 * 2 along with this work; if not, write to the Free Software Foundation,
17 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 18 *
19 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 20 * or visit www.oracle.com if you need additional information or have any
21 21 * questions.
22 22 *
23 23 */
24 24
25 25 #include "precompiled.hpp"
26 26 #include "gc/g1/g1CollectedHeap.inline.hpp"
27 27 #include "gc/g1/g1IHOPControl.hpp"
28 28 #include "gc/g1/g1Predictions.hpp"
29 29 #include "gc/g1/g1Trace.hpp"
30 30 #include "logging/log.hpp"
31 31
32 32 G1IHOPControl::G1IHOPControl(double initial_ihop_percent) :
33 33 _initial_ihop_percent(initial_ihop_percent),
34 34 _target_occupancy(0),
35 35 _last_allocation_time_s(0.0),
36 36 _last_allocated_bytes(0)
37 37 {
38 38 assert(_initial_ihop_percent >= 0.0 && _initial_ihop_percent <= 100.0, "Initial IHOP value must be between 0 and 100 but is %.3f", initial_ihop_percent);
39 39 }
40 40
41 41 void G1IHOPControl::update_target_occupancy(size_t new_target_occupancy) {
42 42 log_debug(gc, ihop)("Target occupancy update: old: " SIZE_FORMAT "B, new: " SIZE_FORMAT "B",
43 43 _target_occupancy, new_target_occupancy);
44 44 _target_occupancy = new_target_occupancy;
45 45 }
46 46
47 47 void G1IHOPControl::update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) {
48 48 assert(allocation_time_s >= 0.0, "Allocation time must be positive but is %.3f", allocation_time_s);
49 49
50 50 _last_allocation_time_s = allocation_time_s;
51 51 _last_allocated_bytes = allocated_bytes;
52 52 }
53 53
54 54 void G1IHOPControl::print() {
55 55 assert(_target_occupancy > 0, "Target occupancy still not updated yet.");
56 56 size_t cur_conc_mark_start_threshold = get_conc_mark_start_threshold();
57 57 log_debug(gc, ihop)("Basic information (value update), threshold: " SIZE_FORMAT "B (%1.2f), target occupancy: " SIZE_FORMAT "B, current occupancy: " SIZE_FORMAT "B, "
58 58 "recent allocation size: " SIZE_FORMAT "B, recent allocation duration: %1.2fms, recent old gen allocation rate: %1.2fB/s, recent marking phase length: %1.2fms",
59 59 cur_conc_mark_start_threshold,
60 60 percent_of(cur_conc_mark_start_threshold, _target_occupancy),
61 61 _target_occupancy,
62 62 G1CollectedHeap::heap()->used(),
63 63 _last_allocated_bytes,
64 64 _last_allocation_time_s * 1000.0,
65 65 _last_allocation_time_s > 0.0 ? _last_allocated_bytes / _last_allocation_time_s : 0.0,
66 66 last_marking_length_s() * 1000.0);
67 67 }
68 68
69 69 void G1IHOPControl::send_trace_event(G1NewTracer* tracer) {
70 70 assert(_target_occupancy > 0, "Target occupancy still not updated yet.");
71 71 tracer->report_basic_ihop_statistics(get_conc_mark_start_threshold(),
72 72 _target_occupancy,
73 73 G1CollectedHeap::heap()->used(),
74 74 _last_allocated_bytes,
75 75 _last_allocation_time_s,
76 76 last_marking_length_s());
77 77 }
78 78
79 79 G1StaticIHOPControl::G1StaticIHOPControl(double ihop_percent) :
80 80 G1IHOPControl(ihop_percent),
81 81 _last_marking_length_s(0.0) {
82 82 }
83 83
84 84 G1AdaptiveIHOPControl::G1AdaptiveIHOPControl(double ihop_percent,
85 85 G1Predictions const* predictor,
86 86 size_t heap_reserve_percent,
87 87 size_t heap_waste_percent) :
88 88 G1IHOPControl(ihop_percent),
89 89 _heap_reserve_percent(heap_reserve_percent),
90 90 _heap_waste_percent(heap_waste_percent),
91 91 _predictor(predictor),
92 92 _marking_times_s(10, 0.95),
93 93 _allocation_rate_s(10, 0.95),
94 94 _last_unrestrained_young_size(0)
95 95 {
96 96 }
97 97
98 98 size_t G1AdaptiveIHOPControl::actual_target_threshold() const {
99 99 guarantee(_target_occupancy > 0, "Target occupancy still not updated yet.");
100 100 // The actual target threshold takes the heap reserve and the expected waste in
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101 101 // free space into account.
102 102 // _heap_reserve is that part of the total heap capacity that is reserved for
103 103 // eventual promotion failure.
104 104 // _heap_waste is the amount of space will never be reclaimed in any
105 105 // heap, so can not be used for allocation during marking and must always be
106 106 // considered.
107 107
108 108 double safe_total_heap_percentage = MIN2((double)(_heap_reserve_percent + _heap_waste_percent), 100.0);
109 109
110 110 return (size_t)MIN2(
111 - G1CollectedHeap::heap()->max_capacity() * (100.0 - safe_total_heap_percentage) / 100.0,
111 + G1CollectedHeap::heap()->soft_max_capacity() * (100.0 - safe_total_heap_percentage) / 100.0,
112 112 _target_occupancy * (100.0 - _heap_waste_percent) / 100.0
113 113 );
114 114 }
115 115
116 116 double G1AdaptiveIHOPControl::predict(TruncatedSeq const* seq) const {
117 117 return _predictor->predict_zero_bounded(seq);
118 118 }
119 119
120 120 bool G1AdaptiveIHOPControl::have_enough_data_for_prediction() const {
121 121 return ((size_t)_marking_times_s.num() >= G1AdaptiveIHOPNumInitialSamples) &&
122 122 ((size_t)_allocation_rate_s.num() >= G1AdaptiveIHOPNumInitialSamples);
123 123 }
124 124
125 125 size_t G1AdaptiveIHOPControl::get_conc_mark_start_threshold() {
126 126 if (have_enough_data_for_prediction()) {
127 127 double pred_marking_time = predict(&_marking_times_s);
128 128 double pred_promotion_rate = predict(&_allocation_rate_s);
129 129 size_t pred_promotion_size = (size_t)(pred_marking_time * pred_promotion_rate);
130 130
131 131 size_t predicted_needed_bytes_during_marking =
132 132 pred_promotion_size +
133 133 // In reality we would need the maximum size of the young gen during
134 134 // marking. This is a conservative estimate.
135 135 _last_unrestrained_young_size;
136 136
137 137 size_t internal_threshold = actual_target_threshold();
138 138 size_t predicted_initiating_threshold = predicted_needed_bytes_during_marking < internal_threshold ?
139 139 internal_threshold - predicted_needed_bytes_during_marking :
140 140 0;
141 141 return predicted_initiating_threshold;
142 142 } else {
143 143 // Use the initial value.
144 144 return (size_t)(_initial_ihop_percent * _target_occupancy / 100.0);
145 145 }
146 146 }
147 147
148 148 void G1AdaptiveIHOPControl::update_allocation_info(double allocation_time_s,
149 149 size_t allocated_bytes,
150 150 size_t additional_buffer_size) {
151 151 G1IHOPControl::update_allocation_info(allocation_time_s, allocated_bytes, additional_buffer_size);
152 152
153 153 double allocation_rate = (double) allocated_bytes / allocation_time_s;
154 154 _allocation_rate_s.add(allocation_rate);
155 155
156 156 _last_unrestrained_young_size = additional_buffer_size;
157 157 }
158 158
159 159 void G1AdaptiveIHOPControl::update_marking_length(double marking_length_s) {
160 160 assert(marking_length_s >= 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);
161 161 _marking_times_s.add(marking_length_s);
162 162 }
163 163
164 164 void G1AdaptiveIHOPControl::print() {
165 165 G1IHOPControl::print();
166 166 size_t actual_target = actual_target_threshold();
167 167 log_debug(gc, ihop)("Adaptive IHOP information (value update), threshold: " SIZE_FORMAT "B (%1.2f), internal target occupancy: " SIZE_FORMAT "B, "
168 168 "occupancy: " SIZE_FORMAT "B, additional buffer size: " SIZE_FORMAT "B, predicted old gen allocation rate: %1.2fB/s, "
169 169 "predicted marking phase length: %1.2fms, prediction active: %s",
170 170 get_conc_mark_start_threshold(),
171 171 percent_of(get_conc_mark_start_threshold(), actual_target),
172 172 actual_target,
173 173 G1CollectedHeap::heap()->used(),
174 174 _last_unrestrained_young_size,
175 175 predict(&_allocation_rate_s),
176 176 predict(&_marking_times_s) * 1000.0,
177 177 have_enough_data_for_prediction() ? "true" : "false");
178 178 }
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179 179
180 180 void G1AdaptiveIHOPControl::send_trace_event(G1NewTracer* tracer) {
181 181 G1IHOPControl::send_trace_event(tracer);
182 182 tracer->report_adaptive_ihop_statistics(get_conc_mark_start_threshold(),
183 183 actual_target_threshold(),
184 184 G1CollectedHeap::heap()->used(),
185 185 _last_unrestrained_young_size,
186 186 predict(&_allocation_rate_s),
187 187 predict(&_marking_times_s),
188 188 have_enough_data_for_prediction());
189 +}
190 +
191 +size_t G1AdaptiveIHOPControl::predict_unstrained_buffer_size() const {
192 + // Besides the young size, the promotion bytes of Prepare Mixed and 1st Mixed GC will be counted
193 + return _last_unrestrained_young_size + _last_allocated_bytes * 2;
189 194 }
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