1 /*
2 * Copyright (c) 2015, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/g1/g1CollectedHeap.inline.hpp"
27 #include "gc/g1/g1ErgoVerbose.hpp"
28 #include "gc/g1/g1IHOPControl.hpp"
29 #include "gc/g1/g1Predictions.hpp"
30 #include "gc/shared/gcTrace.hpp"
31
32 G1IHOPControl::G1IHOPControl(double initial_ihop_percent, size_t target_occupancy) :
33 _ihop_percent(initial_ihop_percent),
34 _target_occupancy(target_occupancy) {
35 assert(_ihop_percent >= 0.0 && _ihop_percent <= 100.0, "Initial IHOP value must be between 0 and 100 but is %.3f", initial_ihop_percent);
36 }
37
38 G1StaticIHOPControl::G1StaticIHOPControl(double ihop_percent, size_t target_occupancy) :
39 G1IHOPControl(ihop_percent, target_occupancy),
40 _last_allocation_time_s(0.0),
41 _last_allocated_bytes(0),
42 _last_marking_length_s(0.0) {
43 assert(_target_occupancy > 0, "Target occupancy must be larger than zero.");
44 }
45
46 void G1StaticIHOPControl::print() {
47 ergo_verbose6(ErgoIHOP,
48 "basic information",
49 ergo_format_reason("value update")
50 ergo_format_byte_perc("threshold")
51 ergo_format_byte("target occupancy")
52 ergo_format_byte("current occupancy")
53 ergo_format_double("recent old gen allocation rate")
54 ergo_format_ms("recent marking phase length"),
55 get_conc_mark_start_threshold(),
56 (double) get_conc_mark_start_threshold() / _target_occupancy * 100.0,
57 _target_occupancy,
58 G1CollectedHeap::heap()->used(),
59 _last_allocation_time_s > 0.0 ? _last_allocated_bytes / _last_allocation_time_s : 0.0,
60 _last_marking_length_s * 1000.0);
61 }
62
63 void G1StaticIHOPControl::send_jfr_event(G1NewTracer* tracer) {
64 tracer->report_basic_ihop_statistics(get_conc_mark_start_threshold(),
65 _target_occupancy,
66 G1CollectedHeap::heap()->used(),
67 _last_allocated_bytes,
68 _last_allocation_time_s,
69 _last_marking_length_s);
70 }
71
72 #ifndef PRODUCT
73 static void test_update(G1IHOPControl* ctrl, double alloc_time, size_t alloc_amount, size_t young_size, double mark_time) {
74 for (int i = 0; i < 100; i++) {
75 ctrl->update_allocation_info(alloc_time, alloc_amount, young_size);
76 ctrl->update_time_to_mixed(mark_time);
77 }
78 }
79
80 void G1StaticIHOPControl::test() {
81 size_t const initial_ihop = 45;
82
83 G1StaticIHOPControl ctrl(initial_ihop, 100);
84 size_t threshold;
85
86 threshold = ctrl.get_conc_mark_start_threshold();
87 assert(threshold == initial_ihop,
88 "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_ihop, threshold);
89
90 ctrl.update_allocation_info(100.0, 100, 100);
91 threshold = ctrl.get_conc_mark_start_threshold();
92 assert(threshold == initial_ihop,
93 "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_ihop, threshold);
94
95 ctrl.update_time_to_mixed(1000.0);
96 threshold = ctrl.get_conc_mark_start_threshold();
97 assert(threshold == initial_ihop,
98 "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_ihop, threshold);
99
100 // Whatever we pass, the IHOP value must stay the same.
101 test_update(&ctrl, 2, 10, 10, 3);
102 threshold = ctrl.get_conc_mark_start_threshold();
103 assert(threshold == initial_ihop,
104 "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_ihop, threshold);
105
106 test_update(&ctrl, 12, 10, 10, 3);
107 threshold = ctrl.get_conc_mark_start_threshold();
108 assert(threshold == initial_ihop,
109 "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_ihop, threshold);
110 }
111 #endif
112
113 G1AdaptiveIHOPControl::G1AdaptiveIHOPControl(double ihop_percent, size_t initial_target_occupancy, G1Predictions const* predictor) :
114 G1IHOPControl(ihop_percent, initial_target_occupancy),
115 _predictor(predictor),
116 _marking_times_s(10, 0.95),
117 _allocation_rate_s(10, 0.95),
118 _prev_unrestrained_young_size(0),
119 _current_threshold(0.0)
120 {
121 recalculate();
122 }
123
124 void G1AdaptiveIHOPControl::recalculate() {
125 if (have_enough_data_for_prediction()) {
126 double pred_marking_time = _predictor->get_new_prediction(&_marking_times_s);
127 double pred_promotion_rate = _predictor->get_new_prediction(&_allocation_rate_s);
128
129 size_t predicted_needed_bytes_during_marking =
130 (pred_marking_time * pred_promotion_rate +
131 _prev_unrestrained_young_size); // In reality we would need the size of the young gen of the first mixed GC. This is a conservative estimate.
132 size_t predicted_initiating_threshold = predicted_needed_bytes_during_marking < _target_occupancy ?
133 _target_occupancy - predicted_needed_bytes_during_marking :
134 0;
135 _current_threshold = predicted_initiating_threshold;
136 } else {
137 // Use the initial value.
138 _current_threshold = _ihop_percent * _target_occupancy / 100.0;
139 }
140 }
141
142 bool G1AdaptiveIHOPControl::have_enough_data_for_prediction() const {
143 return (_marking_times_s.num() > 2) && (_allocation_rate_s.num() > 2);
144 }
145
146 void G1AdaptiveIHOPControl::set_target_occupancy(size_t target_occupancy) {
147 _target_occupancy = target_occupancy;
148 }
149
150 size_t G1AdaptiveIHOPControl::get_conc_mark_start_threshold() {
151 recalculate();
152 return _current_threshold;
153 }
154
155 void G1AdaptiveIHOPControl::update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) {
156 assert(allocation_time_s >= 0.0, "Allocation time must be positive but is %.3f", allocation_time_s);
157 double allocation_rate = (double) allocated_bytes / allocation_time_s;
158 _allocation_rate_s.add(allocation_rate);
159
160 _last_allocation_bytes = allocated_bytes;
161 _prev_unrestrained_young_size = additional_buffer_size;
162 }
163
164 void G1AdaptiveIHOPControl::update_time_to_mixed(double marking_length_s) {
165 assert(marking_length_s >= 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);
166 _marking_times_s.add(marking_length_s);
167 }
168
169 void G1AdaptiveIHOPControl::print() {
170 ergo_verbose6(ErgoIHOP,
171 "basic information",
172 ergo_format_reason("value update")
173 ergo_format_byte_perc("threshold")
174 ergo_format_byte("target threshold")
175 ergo_format_byte("current occupancy")
176 ergo_format_double("recent old gen allocation rate")
177 ergo_format_double("recent marking phase length"),
178 get_conc_mark_start_threshold(),
179 _target_occupancy > 0 ? (double) get_conc_mark_start_threshold() / _target_occupancy * 100.0 : 0.0,
180 _target_occupancy,
181 G1CollectedHeap::heap()->used(),
182 _allocation_rate_s.last(),
183 _marking_times_s.last()
184 );
185 ergo_verbose3(ErgoIHOP,
186 "adaptive IHOP information",
187 ergo_format_reason("value update")
188 ergo_format_double("predicted old gen allocation rate")
189 ergo_format_double("predicted marking phase length")
190 ergo_format_str("prediction active"),
191 _predictor->get_new_prediction(&_allocation_rate_s),
192 _predictor->get_new_prediction(&_marking_times_s),
193 have_enough_data_for_prediction() ? "true" : "false"
194 );
195 }
196
197 void G1AdaptiveIHOPControl::send_jfr_event(G1NewTracer* tracer) {
198 tracer->report_basic_ihop_statistics(get_conc_mark_start_threshold(),
199 _target_occupancy,
200 G1CollectedHeap::heap()->used(),
201 _last_allocation_bytes,
202 _allocation_rate_s.last(),
203 _marking_times_s.last());
204 tracer->report_adaptive_ihop_statistics(_prev_unrestrained_young_size,
205 _predictor->get_new_prediction(&_allocation_rate_s),
206 _predictor->get_new_prediction(&_marking_times_s),
207 have_enough_data_for_prediction());
208 }
209
210 #ifndef PRODUCT
211 void G1AdaptiveIHOPControl::test() {
212 size_t const initial_threshold = 45;
213 size_t const young_size = 10;
214 size_t const target_size = 100;
215
216 // The final IHOP value is always
217 // target_size - (young_size + alloc_amount/alloc_time * marking_time)
218
219 G1Predictions pred(0.95);
220 G1AdaptiveIHOPControl ctrl(initial_threshold, target_size, &pred);
221
222 // First "load".
223 size_t const alloc_time1 = 2;
224 size_t const alloc_amount1 = 10;
225 size_t const marking_time1 = 2;
226 size_t const settled_ihop1 = target_size - (young_size + alloc_amount1/alloc_time1 * marking_time1);
227
228 size_t threshold;
229 threshold = ctrl.get_conc_mark_start_threshold();
230 assert(threshold == initial_threshold,
231 "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_threshold, threshold);
232 ctrl.update_allocation_info(alloc_time1, alloc_amount1, young_size);
233 ctrl.update_time_to_mixed(marking_time1);
234 // Not enough data yet.
235 threshold = ctrl.get_conc_mark_start_threshold();
236 assert(threshold == initial_threshold,
237 "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_threshold, threshold);
238 // Not enough data yet.
239 ctrl.update_allocation_info(alloc_time1, alloc_amount1, young_size);
240 ctrl.update_time_to_mixed(marking_time1);
241 threshold = ctrl.get_conc_mark_start_threshold();
242 assert(threshold == initial_threshold,
243 "Expected IHOP threshold of " SIZE_FORMAT " but is " SIZE_FORMAT, initial_threshold, threshold);
244
245 test_update(&ctrl, alloc_time1, alloc_amount1, young_size, marking_time1);
246
247 threshold = ctrl.get_conc_mark_start_threshold();
248 assert(threshold == settled_ihop1,
249 "Expected IHOP threshold to settle at " SIZE_FORMAT " but is " SIZE_FORMAT, settled_ihop1, threshold);
250
251 // Second "load". A bit higher allocation rate.
252 size_t const alloc_time2 = 2;
253 size_t const alloc_amount2 = 30;
254 size_t const marking_time2 = 2;
255 size_t const settled_ihop2 = target_size - (young_size + alloc_amount2/alloc_time2 * marking_time2);
256
257 test_update(&ctrl, alloc_time2, alloc_amount2, young_size, marking_time2);
258
259 threshold = ctrl.get_conc_mark_start_threshold();
260 assert(threshold < settled_ihop1,
261 "Expected IHOP threshold to settle at a value lower than " SIZE_FORMAT " but is " SIZE_FORMAT, settled_ihop1, threshold);
262
263 // Third "load". Very high (impossible) allocation rate.
264 size_t const alloc_time3 = 1;
265 size_t const alloc_amount3 = 50;
266 size_t const marking_time3 = 2;
267 size_t const settled_ihop3 = 0; // target_size - (young_size + alloc_amount2/alloc_time2 * marking_time2);
268
269 test_update(&ctrl, alloc_time3, alloc_amount3, young_size, marking_time3);
270 threshold = ctrl.get_conc_mark_start_threshold();
271
272 assert(threshold == settled_ihop3,
273 "Expected IHOP threshold to settle at " SIZE_FORMAT " but is " SIZE_FORMAT, settled_ihop3, threshold);
274
275 // And back to some arbitrary value.
276 test_update(&ctrl, alloc_time2, alloc_amount2, young_size, marking_time2);
277
278 threshold = ctrl.get_conc_mark_start_threshold();
279 assert(threshold > settled_ihop3,
280 "Expected IHOP threshold to settle at value larger than " SIZE_FORMAT " but is " SIZE_FORMAT, settled_ihop3, threshold);
281 }
282
283 void IHOP_test() {
284 G1StaticIHOPControl::test();
285 G1AdaptiveIHOPControl::test();
286 }
287 #endif