1 /*
2 * Copyright Amazon.com Inc. 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
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7 * published by the Free Software Foundation.
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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).
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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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24 #include "precompiled.hpp"
25
26 #include "gc/shenandoah/shenandoahAgeCensus.hpp"
27 #include "unittest.hpp"
28
29 class ShenandoahAgeCensusTest : public ::testing::Test {
30 protected:
31 static constexpr size_t MinimumPopulationSize = 4*K;
32 static constexpr size_t InitialPopulationSize = MinimumPopulationSize * 1000;
33
34 size_t _cohorts_count = ShenandoahAgeCensus::MAX_COHORTS;
35 double _mortality_rates[ShenandoahAgeCensus::MAX_COHORTS];
36 size_t _cohort_populations[ShenandoahAgeCensus::MAX_COHORTS];
37
38 ShenandoahAgeCensusTest()
39 : _mortality_rates{0.9, 0.7, 0.5, 0.3, 0.09, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
40 {
41 build_cohort_populations(_mortality_rates, _cohort_populations, _cohorts_count);
42 }
43
44 static void add_population(ShenandoahAgeCensus& census, const uint age, const size_t population_words) {
45 CENSUS_NOISE(census.add(age, 0, 0, population_words, 0));
46 NO_CENSUS_NOISE(census.add(age, 0, population_words, 0));
47 }
48
49 void update(ShenandoahAgeCensus& census, size_t cohorts) const {
50 for (uint i = 1; i < cohorts; i++) {
51 add_population(census, i, _cohort_populations[i]);
52 }
53 census.update_census(_cohort_populations[0]);
54 }
55
56 void update(ShenandoahAgeCensus& census) const {
57 update(census, _cohorts_count);
58 }
59
60 size_t get_total_population_older_than(const size_t min_cohort_age) const {
61 size_t total = 0;
62 for (size_t i = 0; i < _cohorts_count; i++) {
63 if (i >= min_cohort_age) {
64 total += _cohort_populations[i];
65 }
66 }
67 return total;
68 }
69
70 void promote_all_tenurable(const size_t tenuring_threshold) {
71 for (size_t i = 0; i < _cohorts_count; i++) {
72 if (i > tenuring_threshold) {
73 _cohort_populations[i] = 0;
74 }
75 }
76 }
77
78 static void build_cohort_populations(const double mortality_rates[], size_t cohort_populations[], const size_t cohorts) {
79 cohort_populations[0] = InitialPopulationSize;
80 for (size_t i = 1; i < cohorts; i++) {
81 cohort_populations[i] = cohort_populations[i - 1] * (1.0 - mortality_rates[i - 1]);
82 }
83 }
84 };
85
86 TEST_F(ShenandoahAgeCensusTest, initialize) {
87 const ShenandoahAgeCensus census(1);
88 EXPECT_EQ(census.tenuring_threshold(), ShenandoahAgeCensus::MAX_COHORTS);
89 }
90
91 TEST_F(ShenandoahAgeCensusTest, ignore_small_populations) {
92 // Small populations are ignored so we do not return early before reaching the youngest cohort.
93 ShenandoahAgeCensus census(1);
94 add_population(census,1, 32);
95 add_population(census,1, 32);
96 census.update_census(64);
97 EXPECT_EQ(1u, census.tenuring_threshold());
98 }
99
100 TEST_F(ShenandoahAgeCensusTest, find_high_mortality_rate) {
101 ShenandoahAgeCensus census(1);
102
103 // Initial threshold, no data
104 EXPECT_EQ(16u, census.tenuring_threshold());
105
106 // Provide population data for 1st cohort. Previous epoch has no population data so our
107 // algorithm skips over all cohorts, leaving tenuring threshold at 1.
108 update(census, 1);
109 EXPECT_EQ(1u, census.tenuring_threshold());
110
111 // Mortality rate of 1st cohort at age 1 is 0.9, we don't want to promote here. Move threshold to 2.
112 update(census, 2);
113 EXPECT_EQ(2u, census.tenuring_threshold());
114
115 // Mortality rate of 1st cohort at age 2 is 0.7, we don't want to promote here. Move threshold to 3.
116 update(census, 3);
117 EXPECT_EQ(3u, census.tenuring_threshold());
118
119 // Mortality rate of 1st cohort at age 3 is 0.5, we don't want to promote here. Move threshold to 4.
120 update(census, 4);
121 EXPECT_EQ(4u, census.tenuring_threshold());
122
123 // Mortality rate of 1st cohort at age 4 is 0.3, we don't want to promote here. Move threshold to 5.
124 update(census, 5);
125 EXPECT_EQ(5u, census.tenuring_threshold());
126
127 // Mortality rate of 1st cohort at age 5 is 0.09, this is less than the mortality rate threshold. It
128 // is okay to tenure objects older than 5 now. Keep threshold at 5.
129 update(census, 6);
130 EXPECT_EQ(5u, census.tenuring_threshold());
131
132 // Mortality rate at this age is 0. Keep tenuring threshold at 5.
133 update(census, 7);
134 EXPECT_EQ(5u, census.tenuring_threshold());
135 }
136
137 TEST_F(ShenandoahAgeCensusTest, ignore_mortality_caused_by_promotions) {
138 ShenandoahAgeCensus census(1);
139
140 // Simulate a sequence of censuses with the same mortality rate. Each one will see a
141 // mortality rate above the tenuring threshold and raise the tenuring threshold by one.
142 update(census, 1);
143 update(census, 2);
144 update(census, 3);
145 update(census, 4);
146 update(census, 5);
147
148 EXPECT_EQ(5u, census.tenuring_threshold());
149
150 // Simulate the effect of promoting all objects above the tenuring threshold
151 // out of the young generation. This will look like a very high (100%) mortality
152 // rate for these cohorts. However, we do _not_ want to raise the threshold in
153 // this case because these objects haven't really "died", they have just been
154 // tenured.
155 promote_all_tenurable(census.tenuring_threshold());
156 update(census);
157
158 // We want this to stay at 5 - the mortality in 1st cohort at age 6 was caused by expected promotions.
159 EXPECT_EQ(5u, census.tenuring_threshold());
160 }