0
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1 /*
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2 * Copyright 2002-2007 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 #include "incls/_precompiled.incl"
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26 #include "incls/_psAdaptiveSizePolicy.cpp.incl"
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27
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28 #include <math.h>
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29
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30 PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size,
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31 size_t init_promo_size,
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32 size_t init_survivor_size,
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33 size_t intra_generation_alignment,
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34 double gc_pause_goal_sec,
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35 double gc_minor_pause_goal_sec,
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36 uint gc_cost_ratio) :
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37 AdaptiveSizePolicy(init_eden_size,
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38 init_promo_size,
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39 init_survivor_size,
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40 gc_pause_goal_sec,
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41 gc_cost_ratio),
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42 _collection_cost_margin_fraction(AdaptiveSizePolicyCollectionCostMargin/
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43 100.0),
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44 _intra_generation_alignment(intra_generation_alignment),
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45 _live_at_last_full_gc(init_promo_size),
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46 _gc_minor_pause_goal_sec(gc_minor_pause_goal_sec),
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47 _latest_major_mutator_interval_seconds(0),
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48 _young_gen_change_for_major_pause_count(0)
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49 {
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50 // Sizing policy statistics
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51 _avg_major_pause =
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52 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
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53 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
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54 _avg_major_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
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55
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56 _avg_base_footprint = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
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57 _major_pause_old_estimator =
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58 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
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59 _major_pause_young_estimator =
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60 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
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61 _major_collection_estimator =
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62 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
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63
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64 _young_gen_size_increment_supplement = YoungGenerationSizeSupplement;
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65 _old_gen_size_increment_supplement = TenuredGenerationSizeSupplement;
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66
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67 // Start the timers
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68 _major_timer.start();
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69
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70 _old_gen_policy_is_ready = false;
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71 }
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72
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73 void PSAdaptiveSizePolicy::major_collection_begin() {
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74 // Update the interval time
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75 _major_timer.stop();
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76 // Save most recent collection time
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77 _latest_major_mutator_interval_seconds = _major_timer.seconds();
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78 _major_timer.reset();
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79 _major_timer.start();
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80 }
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81
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82 void PSAdaptiveSizePolicy::update_minor_pause_old_estimator(
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83 double minor_pause_in_ms) {
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84 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
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85 _minor_pause_old_estimator->update(promo_size_in_mbytes,
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86 minor_pause_in_ms);
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87 }
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88
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89 void PSAdaptiveSizePolicy::major_collection_end(size_t amount_live,
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90 GCCause::Cause gc_cause) {
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91 // Update the pause time.
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92 _major_timer.stop();
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93
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94 if (gc_cause != GCCause::_java_lang_system_gc ||
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95 UseAdaptiveSizePolicyWithSystemGC) {
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96 double major_pause_in_seconds = _major_timer.seconds();
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97 double major_pause_in_ms = major_pause_in_seconds * MILLIUNITS;
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98
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99 // Sample for performance counter
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100 _avg_major_pause->sample(major_pause_in_seconds);
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101
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102 // Cost of collection (unit-less)
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103 double collection_cost = 0.0;
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104 if ((_latest_major_mutator_interval_seconds > 0.0) &&
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105 (major_pause_in_seconds > 0.0)) {
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106 double interval_in_seconds =
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107 _latest_major_mutator_interval_seconds + major_pause_in_seconds;
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108 collection_cost =
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109 major_pause_in_seconds / interval_in_seconds;
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110 avg_major_gc_cost()->sample(collection_cost);
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111
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112 // Sample for performance counter
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113 _avg_major_interval->sample(interval_in_seconds);
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114 }
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115
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116 // Calculate variables used to estimate pause time vs. gen sizes
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117 double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
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118 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
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119 _major_pause_old_estimator->update(promo_size_in_mbytes,
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120 major_pause_in_ms);
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121 _major_pause_young_estimator->update(eden_size_in_mbytes,
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122 major_pause_in_ms);
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123
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124 if (PrintAdaptiveSizePolicy && Verbose) {
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125 gclog_or_tty->print("psAdaptiveSizePolicy::major_collection_end: "
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126 "major gc cost: %f average: %f", collection_cost,
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127 avg_major_gc_cost()->average());
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128 gclog_or_tty->print_cr(" major pause: %f major period %f",
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129 major_pause_in_ms,
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130 _latest_major_mutator_interval_seconds * MILLIUNITS);
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131 }
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132
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133 // Calculate variable used to estimate collection cost vs. gen sizes
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134 assert(collection_cost >= 0.0, "Expected to be non-negative");
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135 _major_collection_estimator->update(promo_size_in_mbytes,
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136 collection_cost);
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137 }
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138
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139 // Update the amount live at the end of a full GC
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140 _live_at_last_full_gc = amount_live;
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141
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142 // The policy does not have enough data until at least some major collections
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143 // have been done.
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144 if (_avg_major_pause->count() >= AdaptiveSizePolicyReadyThreshold) {
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145 _old_gen_policy_is_ready = true;
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146 }
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147
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148 // Interval times use this timer to measure the interval that
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149 // the mutator runs. Reset after the GC pause has been measured.
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150 _major_timer.reset();
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151 _major_timer.start();
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152 }
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153
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154 // If the remaining free space in the old generation is less that
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155 // that expected to be needed by the next collection, do a full
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156 // collection now.
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157 bool PSAdaptiveSizePolicy::should_full_GC(size_t old_free_in_bytes) {
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158
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159 // A similar test is done in the scavenge's should_attempt_scavenge(). If
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160 // this is changed, decide if that test should also be changed.
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161 bool result = padded_average_promoted_in_bytes() > (float) old_free_in_bytes;
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162 if (PrintGCDetails && Verbose) {
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163 if (result) {
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164 gclog_or_tty->print(" full after scavenge: ");
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165 } else {
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166 gclog_or_tty->print(" no full after scavenge: ");
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167 }
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168 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
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169 " padded_average_promoted " SIZE_FORMAT
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170 " free in old gen " SIZE_FORMAT,
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171 (size_t) average_promoted_in_bytes(),
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172 (size_t) padded_average_promoted_in_bytes(),
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173 old_free_in_bytes);
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174 }
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175 return result;
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176 }
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177
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178 void PSAdaptiveSizePolicy::clear_generation_free_space_flags() {
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179
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180 AdaptiveSizePolicy::clear_generation_free_space_flags();
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181
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182 set_change_old_gen_for_min_pauses(0);
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183
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184 set_change_young_gen_for_maj_pauses(0);
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185 }
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186
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187
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188 // If this is not a full GC, only test and modify the young generation.
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189
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190 void PSAdaptiveSizePolicy::compute_generation_free_space(size_t young_live,
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191 size_t eden_live,
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192 size_t old_live,
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193 size_t perm_live,
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194 size_t cur_eden,
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195 size_t max_old_gen_size,
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196 size_t max_eden_size,
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197 bool is_full_gc,
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198 GCCause::Cause gc_cause) {
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199
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200 // Update statistics
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201 // Time statistics are updated as we go, update footprint stats here
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202 _avg_base_footprint->sample(BaseFootPrintEstimate + perm_live);
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203 avg_young_live()->sample(young_live);
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204 avg_eden_live()->sample(eden_live);
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205 if (is_full_gc) {
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206 // old_live is only accurate after a full gc
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207 avg_old_live()->sample(old_live);
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208 }
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209
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210 // This code used to return if the policy was not ready , i.e.,
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211 // policy_is_ready() returning false. The intent was that
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212 // decisions below needed major collection times and so could
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213 // not be made before two major collections. A consequence was
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214 // adjustments to the young generation were not done until after
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215 // two major collections even if the minor collections times
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216 // exceeded the requested goals. Now let the young generation
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217 // adjust for the minor collection times. Major collection times
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218 // will be zero for the first collection and will naturally be
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219 // ignored. Tenured generation adjustments are only made at the
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220 // full collections so until the second major collection has
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221 // been reached, no tenured generation adjustments will be made.
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222
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223 // Until we know better, desired promotion size uses the last calculation
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224 size_t desired_promo_size = _promo_size;
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225
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226 // Start eden at the current value. The desired value that is stored
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227 // in _eden_size is not bounded by constraints of the heap and can
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228 // run away.
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229 //
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230 // As expected setting desired_eden_size to the current
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231 // value of desired_eden_size as a starting point
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232 // caused desired_eden_size to grow way too large and caused
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233 // an overflow down stream. It may have improved performance in
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234 // some case but is dangerous.
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235 size_t desired_eden_size = cur_eden;
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236
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237 #ifdef ASSERT
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238 size_t original_promo_size = desired_promo_size;
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239 size_t original_eden_size = desired_eden_size;
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240 #endif
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241
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242 // Cache some values. There's a bit of work getting these, so
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243 // we might save a little time.
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244 const double major_cost = major_gc_cost();
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245 const double minor_cost = minor_gc_cost();
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246
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247 // Used for diagnostics
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248 clear_generation_free_space_flags();
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249
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250 // Limits on our growth
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251 size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average());
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252
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253 // This method sets the desired eden size. That plus the
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254 // desired survivor space sizes sets the desired young generation
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255 // size. This methods does not know what the desired survivor
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256 // size is but expects that other policy will attempt to make
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257 // the survivor sizes compatible with the live data in the
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258 // young generation. This limit is an estimate of the space left
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259 // in the young generation after the survivor spaces have been
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260 // subtracted out.
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261 size_t eden_limit = max_eden_size;
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262
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263 // But don't force a promo size below the current promo size. Otherwise,
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264 // the promo size will shrink for no good reason.
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265 promo_limit = MAX2(promo_limit, _promo_size);
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266
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267 const double gc_cost_limit = GCTimeLimit/100.0;
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268
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269 // Which way should we go?
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270 // if pause requirement is not met
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271 // adjust size of any generation with average paus exceeding
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272 // the pause limit. Adjust one pause at a time (the larger)
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273 // and only make adjustments for the major pause at full collections.
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274 // else if throughput requirement not met
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275 // adjust the size of the generation with larger gc time. Only
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276 // adjust one generation at a time.
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277 // else
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278 // adjust down the total heap size. Adjust down the larger of the
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279 // generations.
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280
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281 // Add some checks for a threshhold for a change. For example,
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282 // a change less than the necessary alignment is probably not worth
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283 // attempting.
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284
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285
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286 if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
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287 (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
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288 //
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289 // Check pauses
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290 //
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291 // Make changes only to affect one of the pauses (the larger)
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292 // at a time.
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293 adjust_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
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294
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295 } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
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296 // Adjust only for the minor pause time goal
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297 adjust_for_minor_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
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298
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299 } else if(adjusted_mutator_cost() < _throughput_goal) {
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300 // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
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301 // This sometimes resulted in skipping to the minimize footprint
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302 // code. Change this to try and reduce GC time if mutator time is
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303 // negative for whatever reason. Or for future consideration,
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304 // bail out of the code if mutator time is negative.
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305 //
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306 // Throughput
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307 //
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308 assert(major_cost >= 0.0, "major cost is < 0.0");
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309 assert(minor_cost >= 0.0, "minor cost is < 0.0");
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310 // Try to reduce the GC times.
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311 adjust_for_throughput(is_full_gc, &desired_promo_size, &desired_eden_size);
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312
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313 } else {
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314
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315 // Be conservative about reducing the footprint.
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316 // Do a minimum number of major collections first.
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317 // Have reasonable averages for major and minor collections costs.
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318 if (UseAdaptiveSizePolicyFootprintGoal &&
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319 young_gen_policy_is_ready() &&
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320 avg_major_gc_cost()->average() >= 0.0 &&
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321 avg_minor_gc_cost()->average() >= 0.0) {
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322 size_t desired_sum = desired_eden_size + desired_promo_size;
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323 desired_eden_size = adjust_eden_for_footprint(desired_eden_size,
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324 desired_sum);
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325 if (is_full_gc) {
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326 set_decide_at_full_gc(decide_at_full_gc_true);
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327 desired_promo_size = adjust_promo_for_footprint(desired_promo_size,
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328 desired_sum);
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329 }
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330 }
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331 }
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332
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333 // Note we make the same tests as in the code block below; the code
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334 // seems a little easier to read with the printing in another block.
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335 if (PrintAdaptiveSizePolicy) {
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336 if (desired_promo_size > promo_limit) {
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337 // "free_in_old_gen" was the original value for used for promo_limit
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338 size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
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339 gclog_or_tty->print_cr(
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340 "PSAdaptiveSizePolicy::compute_generation_free_space limits:"
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341 " desired_promo_size: " SIZE_FORMAT
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342 " promo_limit: " SIZE_FORMAT
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343 " free_in_old_gen: " SIZE_FORMAT
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344 " max_old_gen_size: " SIZE_FORMAT
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345 " avg_old_live: " SIZE_FORMAT,
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346 desired_promo_size, promo_limit, free_in_old_gen,
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347 max_old_gen_size, (size_t) avg_old_live()->average());
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348 }
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349 if (desired_eden_size > eden_limit) {
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350 gclog_or_tty->print_cr(
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351 "AdaptiveSizePolicy::compute_generation_free_space limits:"
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352 " desired_eden_size: " SIZE_FORMAT
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353 " old_eden_size: " SIZE_FORMAT
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354 " eden_limit: " SIZE_FORMAT
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355 " cur_eden: " SIZE_FORMAT
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356 " max_eden_size: " SIZE_FORMAT
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357 " avg_young_live: " SIZE_FORMAT,
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358 desired_eden_size, _eden_size, eden_limit, cur_eden,
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359 max_eden_size, (size_t)avg_young_live()->average());
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360 }
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361 if (gc_cost() > gc_cost_limit) {
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362 gclog_or_tty->print_cr(
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363 "AdaptiveSizePolicy::compute_generation_free_space: gc time limit"
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364 " gc_cost: %f "
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365 " GCTimeLimit: %d",
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366 gc_cost(), GCTimeLimit);
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367 }
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368 }
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369
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370 // Align everything and make a final limit check
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371 const size_t alignment = _intra_generation_alignment;
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372 desired_eden_size = align_size_up(desired_eden_size, alignment);
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373 desired_eden_size = MAX2(desired_eden_size, alignment);
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374 desired_promo_size = align_size_up(desired_promo_size, alignment);
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375 desired_promo_size = MAX2(desired_promo_size, alignment);
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376
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377 eden_limit = align_size_down(eden_limit, alignment);
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378 promo_limit = align_size_down(promo_limit, alignment);
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379
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380 // Is too much time being spent in GC?
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381 // Is the heap trying to grow beyond it's limits?
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382
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383 const size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
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384 if (desired_promo_size > free_in_old_gen && desired_eden_size > eden_limit) {
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385
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386 // eden_limit is the upper limit on the size of eden based on
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387 // the maximum size of the young generation and the sizes
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388 // of the survivor space.
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389 // The question being asked is whether the gc costs are high
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390 // and the space being recovered by a collection is low.
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391 // free_in_young_gen is the free space in the young generation
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392 // after a collection and promo_live is the free space in the old
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393 // generation after a collection.
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394 //
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395 // Use the minimum of the current value of the live in the
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396 // young gen or the average of the live in the young gen.
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397 // If the current value drops quickly, that should be taken
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398 // into account (i.e., don't trigger if the amount of free
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399 // space has suddenly jumped up). If the current is much
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400 // higher than the average, use the average since it represents
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401 // the longer term behavor.
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402 const size_t live_in_eden = MIN2(eden_live, (size_t) avg_eden_live()->average());
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403 const size_t free_in_eden = eden_limit > live_in_eden ?
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404 eden_limit - live_in_eden : 0;
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405 const size_t total_free_limit = free_in_old_gen + free_in_eden;
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406 const size_t total_mem = max_old_gen_size + max_eden_size;
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407 const double mem_free_limit = total_mem * (GCHeapFreeLimit/100.0);
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408 if (PrintAdaptiveSizePolicy && (Verbose ||
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409 (total_free_limit < (size_t) mem_free_limit))) {
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410 gclog_or_tty->print_cr(
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411 "PSAdaptiveSizePolicy::compute_generation_free_space limits:"
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412 " promo_limit: " SIZE_FORMAT
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413 " eden_limit: " SIZE_FORMAT
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414 " total_free_limit: " SIZE_FORMAT
|
|
415 " max_old_gen_size: " SIZE_FORMAT
|
|
416 " max_eden_size: " SIZE_FORMAT
|
|
417 " mem_free_limit: " SIZE_FORMAT,
|
|
418 promo_limit, eden_limit, total_free_limit,
|
|
419 max_old_gen_size, max_eden_size,
|
|
420 (size_t) mem_free_limit);
|
|
421 }
|
|
422
|
|
423 if (is_full_gc) {
|
|
424 if (gc_cost() > gc_cost_limit &&
|
|
425 total_free_limit < (size_t) mem_free_limit) {
|
|
426 // Collections, on average, are taking too much time, and
|
|
427 // gc_cost() > gc_cost_limit
|
|
428 // we have too little space available after a full gc.
|
|
429 // total_free_limit < mem_free_limit
|
|
430 // where
|
|
431 // total_free_limit is the free space available in
|
|
432 // both generations
|
|
433 // total_mem is the total space available for allocation
|
|
434 // in both generations (survivor spaces are not included
|
|
435 // just as they are not included in eden_limit).
|
|
436 // mem_free_limit is a fraction of total_mem judged to be an
|
|
437 // acceptable amount that is still unused.
|
|
438 // The heap can ask for the value of this variable when deciding
|
|
439 // whether to thrown an OutOfMemory error.
|
|
440 // Note that the gc time limit test only works for the collections
|
|
441 // of the young gen + tenured gen and not for collections of the
|
|
442 // permanent gen. That is because the calculation of the space
|
|
443 // freed by the collection is the free space in the young gen +
|
|
444 // tenured gen.
|
|
445 // Ignore explicit GC's. Ignoring explicit GC's at this level
|
|
446 // is the equivalent of the GC did not happen as far as the
|
|
447 // overhead calculation is concerted (i.e., the flag is not set
|
|
448 // and the count is not affected). Also the average will not
|
|
449 // have been updated unless UseAdaptiveSizePolicyWithSystemGC is on.
|
|
450 if (!GCCause::is_user_requested_gc(gc_cause) &&
|
|
451 !GCCause::is_serviceability_requested_gc(gc_cause)) {
|
|
452 inc_gc_time_limit_count();
|
|
453 if (UseGCOverheadLimit &&
|
|
454 (gc_time_limit_count() > AdaptiveSizePolicyGCTimeLimitThreshold)){
|
|
455 // All conditions have been met for throwing an out-of-memory
|
|
456 _gc_time_limit_exceeded = true;
|
|
457 // Avoid consecutive OOM due to the gc time limit by resetting
|
|
458 // the counter.
|
|
459 reset_gc_time_limit_count();
|
|
460 }
|
|
461 _print_gc_time_limit_would_be_exceeded = true;
|
|
462 }
|
|
463 } else {
|
|
464 // Did not exceed overhead limits
|
|
465 reset_gc_time_limit_count();
|
|
466 }
|
|
467 }
|
|
468 }
|
|
469
|
|
470
|
|
471 // And one last limit check, now that we've aligned things.
|
|
472 if (desired_eden_size > eden_limit) {
|
|
473 // If the policy says to get a larger eden but
|
|
474 // is hitting the limit, don't decrease eden.
|
|
475 // This can lead to a general drifting down of the
|
|
476 // eden size. Let the tenuring calculation push more
|
|
477 // into the old gen.
|
|
478 desired_eden_size = MAX2(eden_limit, cur_eden);
|
|
479 }
|
|
480 desired_promo_size = MIN2(desired_promo_size, promo_limit);
|
|
481
|
|
482
|
|
483 if (PrintAdaptiveSizePolicy) {
|
|
484 // Timing stats
|
|
485 gclog_or_tty->print(
|
|
486 "PSAdaptiveSizePolicy::compute_generation_free_space: costs"
|
|
487 " minor_time: %f"
|
|
488 " major_cost: %f"
|
|
489 " mutator_cost: %f"
|
|
490 " throughput_goal: %f",
|
|
491 minor_gc_cost(), major_gc_cost(), mutator_cost(),
|
|
492 _throughput_goal);
|
|
493
|
|
494 // We give more details if Verbose is set
|
|
495 if (Verbose) {
|
|
496 gclog_or_tty->print( " minor_pause: %f"
|
|
497 " major_pause: %f"
|
|
498 " minor_interval: %f"
|
|
499 " major_interval: %f"
|
|
500 " pause_goal: %f",
|
|
501 _avg_minor_pause->padded_average(),
|
|
502 _avg_major_pause->padded_average(),
|
|
503 _avg_minor_interval->average(),
|
|
504 _avg_major_interval->average(),
|
|
505 gc_pause_goal_sec());
|
|
506 }
|
|
507
|
|
508 // Footprint stats
|
|
509 gclog_or_tty->print( " live_space: " SIZE_FORMAT
|
|
510 " free_space: " SIZE_FORMAT,
|
|
511 live_space(), free_space());
|
|
512 // More detail
|
|
513 if (Verbose) {
|
|
514 gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
|
|
515 " avg_young_live: " SIZE_FORMAT
|
|
516 " avg_old_live: " SIZE_FORMAT,
|
|
517 (size_t)_avg_base_footprint->average(),
|
|
518 (size_t)avg_young_live()->average(),
|
|
519 (size_t)avg_old_live()->average());
|
|
520 }
|
|
521
|
|
522 // And finally, our old and new sizes.
|
|
523 gclog_or_tty->print(" old_promo_size: " SIZE_FORMAT
|
|
524 " old_eden_size: " SIZE_FORMAT
|
|
525 " desired_promo_size: " SIZE_FORMAT
|
|
526 " desired_eden_size: " SIZE_FORMAT,
|
|
527 _promo_size, _eden_size,
|
|
528 desired_promo_size, desired_eden_size);
|
|
529 gclog_or_tty->cr();
|
|
530 }
|
|
531
|
|
532 decay_supplemental_growth(is_full_gc);
|
|
533
|
|
534 set_promo_size(desired_promo_size);
|
|
535 set_eden_size(desired_eden_size);
|
|
536 };
|
|
537
|
|
538 void PSAdaptiveSizePolicy::decay_supplemental_growth(bool is_full_gc) {
|
|
539 // Decay the supplemental increment? Decay the supplement growth
|
|
540 // factor even if it is not used. It is only meant to give a boost
|
|
541 // to the initial growth and if it is not used, then it was not
|
|
542 // needed.
|
|
543 if (is_full_gc) {
|
|
544 // Don't wait for the threshold value for the major collections. If
|
|
545 // here, the supplemental growth term was used and should decay.
|
|
546 if ((_avg_major_pause->count() % TenuredGenerationSizeSupplementDecay)
|
|
547 == 0) {
|
|
548 _old_gen_size_increment_supplement =
|
|
549 _old_gen_size_increment_supplement >> 1;
|
|
550 }
|
|
551 } else {
|
|
552 if ((_avg_minor_pause->count() >= AdaptiveSizePolicyReadyThreshold) &&
|
|
553 (_avg_minor_pause->count() % YoungGenerationSizeSupplementDecay) == 0) {
|
|
554 _young_gen_size_increment_supplement =
|
|
555 _young_gen_size_increment_supplement >> 1;
|
|
556 }
|
|
557 }
|
|
558 }
|
|
559
|
|
560 void PSAdaptiveSizePolicy::adjust_for_minor_pause_time(bool is_full_gc,
|
|
561 size_t* desired_promo_size_ptr, size_t* desired_eden_size_ptr) {
|
|
562
|
|
563 // Adjust the young generation size to reduce pause time of
|
|
564 // of collections.
|
|
565 //
|
|
566 // The AdaptiveSizePolicyInitializingSteps test is not used
|
|
567 // here. It has not seemed to be needed but perhaps should
|
|
568 // be added for consistency.
|
|
569 if (minor_pause_young_estimator()->decrement_will_decrease()) {
|
|
570 // reduce eden size
|
|
571 set_change_young_gen_for_min_pauses(
|
|
572 decrease_young_gen_for_min_pauses_true);
|
|
573 *desired_eden_size_ptr = *desired_eden_size_ptr -
|
|
574 eden_decrement_aligned_down(*desired_eden_size_ptr);
|
|
575 } else {
|
|
576 // EXPERIMENTAL ADJUSTMENT
|
|
577 // Only record that the estimator indicated such an action.
|
|
578 // *desired_eden_size_ptr = *desired_eden_size_ptr + eden_heap_delta;
|
|
579 set_change_young_gen_for_min_pauses(
|
|
580 increase_young_gen_for_min_pauses_true);
|
|
581 }
|
|
582 if (PSAdjustTenuredGenForMinorPause) {
|
|
583 // If the desired eden size is as small as it will get,
|
|
584 // try to adjust the old gen size.
|
|
585 if (*desired_eden_size_ptr <= _intra_generation_alignment) {
|
|
586 // Vary the old gen size to reduce the young gen pause. This
|
|
587 // may not be a good idea. This is just a test.
|
|
588 if (minor_pause_old_estimator()->decrement_will_decrease()) {
|
|
589 set_change_old_gen_for_min_pauses(
|
|
590 decrease_old_gen_for_min_pauses_true);
|
|
591 *desired_promo_size_ptr =
|
|
592 _promo_size - promo_decrement_aligned_down(*desired_promo_size_ptr);
|
|
593 } else {
|
|
594 set_change_old_gen_for_min_pauses(
|
|
595 increase_old_gen_for_min_pauses_true);
|
|
596 size_t promo_heap_delta =
|
|
597 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
|
|
598 if ((*desired_promo_size_ptr + promo_heap_delta) >
|
|
599 *desired_promo_size_ptr) {
|
|
600 *desired_promo_size_ptr =
|
|
601 _promo_size + promo_heap_delta;
|
|
602 }
|
|
603 }
|
|
604 }
|
|
605 }
|
|
606 }
|
|
607
|
|
608 void PSAdaptiveSizePolicy::adjust_for_pause_time(bool is_full_gc,
|
|
609 size_t* desired_promo_size_ptr,
|
|
610 size_t* desired_eden_size_ptr) {
|
|
611
|
|
612 size_t promo_heap_delta = 0;
|
|
613 size_t eden_heap_delta = 0;
|
|
614 // Add some checks for a threshhold for a change. For example,
|
|
615 // a change less than the required alignment is probably not worth
|
|
616 // attempting.
|
|
617 if (is_full_gc) {
|
|
618 set_decide_at_full_gc(decide_at_full_gc_true);
|
|
619 }
|
|
620
|
|
621 if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
|
|
622 adjust_for_minor_pause_time(is_full_gc,
|
|
623 desired_promo_size_ptr,
|
|
624 desired_eden_size_ptr);
|
|
625 // major pause adjustments
|
|
626 } else if (is_full_gc) {
|
|
627 // Adjust for the major pause time only at full gc's because the
|
|
628 // affects of a change can only be seen at full gc's.
|
|
629
|
|
630 // Reduce old generation size to reduce pause?
|
|
631 if (major_pause_old_estimator()->decrement_will_decrease()) {
|
|
632 // reduce old generation size
|
|
633 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
|
|
634 promo_heap_delta = promo_decrement_aligned_down(*desired_promo_size_ptr);
|
|
635 *desired_promo_size_ptr = _promo_size - promo_heap_delta;
|
|
636 } else {
|
|
637 // EXPERIMENTAL ADJUSTMENT
|
|
638 // Only record that the estimator indicated such an action.
|
|
639 // *desired_promo_size_ptr = _promo_size +
|
|
640 // promo_increment_aligned_up(*desired_promo_size_ptr);
|
|
641 set_change_old_gen_for_maj_pauses(increase_old_gen_for_maj_pauses_true);
|
|
642 }
|
|
643 if (PSAdjustYoungGenForMajorPause) {
|
|
644 // If the promo size is at the minimum (i.e., the old gen
|
|
645 // size will not actually decrease), consider changing the
|
|
646 // young gen size.
|
|
647 if (*desired_promo_size_ptr < _intra_generation_alignment) {
|
|
648 // If increasing the young generation will decrease the old gen
|
|
649 // pause, do it.
|
|
650 // During startup there is noise in the statistics for deciding
|
|
651 // on whether to increase or decrease the young gen size. For
|
|
652 // some number of iterations, just try to increase the young
|
|
653 // gen size if the major pause is too long to try and establish
|
|
654 // good statistics for later decisions.
|
|
655 if (major_pause_young_estimator()->increment_will_decrease() ||
|
|
656 (_young_gen_change_for_major_pause_count
|
|
657 <= AdaptiveSizePolicyInitializingSteps)) {
|
|
658 set_change_young_gen_for_maj_pauses(
|
|
659 increase_young_gen_for_maj_pauses_true);
|
|
660 eden_heap_delta = eden_increment_aligned_up(*desired_eden_size_ptr);
|
|
661 *desired_eden_size_ptr = _eden_size + eden_heap_delta;
|
|
662 _young_gen_change_for_major_pause_count++;
|
|
663 } else {
|
|
664 // Record that decreasing the young gen size would decrease
|
|
665 // the major pause
|
|
666 set_change_young_gen_for_maj_pauses(
|
|
667 decrease_young_gen_for_maj_pauses_true);
|
|
668 eden_heap_delta = eden_decrement_aligned_down(*desired_eden_size_ptr);
|
|
669 *desired_eden_size_ptr = _eden_size - eden_heap_delta;
|
|
670 }
|
|
671 }
|
|
672 }
|
|
673 }
|
|
674
|
|
675 if (PrintAdaptiveSizePolicy && Verbose) {
|
|
676 gclog_or_tty->print_cr(
|
|
677 "AdaptiveSizePolicy::compute_generation_free_space "
|
|
678 "adjusting gen sizes for major pause (avg %f goal %f). "
|
|
679 "desired_promo_size " SIZE_FORMAT "desired_eden_size "
|
|
680 SIZE_FORMAT
|
|
681 " promo delta " SIZE_FORMAT " eden delta " SIZE_FORMAT,
|
|
682 _avg_major_pause->average(), gc_pause_goal_sec(),
|
|
683 *desired_promo_size_ptr, *desired_eden_size_ptr,
|
|
684 promo_heap_delta, eden_heap_delta);
|
|
685 }
|
|
686 }
|
|
687
|
|
688 void PSAdaptiveSizePolicy::adjust_for_throughput(bool is_full_gc,
|
|
689 size_t* desired_promo_size_ptr,
|
|
690 size_t* desired_eden_size_ptr) {
|
|
691
|
|
692 // Add some checks for a threshhold for a change. For example,
|
|
693 // a change less than the required alignment is probably not worth
|
|
694 // attempting.
|
|
695 if (is_full_gc) {
|
|
696 set_decide_at_full_gc(decide_at_full_gc_true);
|
|
697 }
|
|
698
|
|
699 if ((gc_cost() + mutator_cost()) == 0.0) {
|
|
700 return;
|
|
701 }
|
|
702
|
|
703 if (PrintAdaptiveSizePolicy && Verbose) {
|
|
704 gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_for_throughput("
|
|
705 "is_full: %d, promo: " SIZE_FORMAT ", cur_eden: " SIZE_FORMAT "): ",
|
|
706 is_full_gc, *desired_promo_size_ptr, *desired_eden_size_ptr);
|
|
707 gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
|
|
708 "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
|
|
709 }
|
|
710
|
|
711 // Tenured generation
|
|
712 if (is_full_gc) {
|
|
713
|
|
714 // Calculate the change to use for the tenured gen.
|
|
715 size_t scaled_promo_heap_delta = 0;
|
|
716 // Can the increment to the generation be scaled?
|
|
717 if (gc_cost() >= 0.0 && major_gc_cost() >= 0.0) {
|
|
718 size_t promo_heap_delta =
|
|
719 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
|
|
720 double scale_by_ratio = major_gc_cost() / gc_cost();
|
|
721 scaled_promo_heap_delta =
|
|
722 (size_t) (scale_by_ratio * (double) promo_heap_delta);
|
|
723 if (PrintAdaptiveSizePolicy && Verbose) {
|
|
724 gclog_or_tty->print_cr(
|
|
725 "Scaled tenured increment: " SIZE_FORMAT " by %f down to "
|
|
726 SIZE_FORMAT,
|
|
727 promo_heap_delta, scale_by_ratio, scaled_promo_heap_delta);
|
|
728 }
|
|
729 } else if (major_gc_cost() >= 0.0) {
|
|
730 // Scaling is not going to work. If the major gc time is the
|
|
731 // larger, give it a full increment.
|
|
732 if (major_gc_cost() >= minor_gc_cost()) {
|
|
733 scaled_promo_heap_delta =
|
|
734 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
|
|
735 }
|
|
736 } else {
|
|
737 // Don't expect to get here but it's ok if it does
|
|
738 // in the product build since the delta will be 0
|
|
739 // and nothing will change.
|
|
740 assert(false, "Unexpected value for gc costs");
|
|
741 }
|
|
742
|
|
743 switch (AdaptiveSizeThroughPutPolicy) {
|
|
744 case 1:
|
|
745 // Early in the run the statistics might not be good. Until
|
|
746 // a specific number of collections have been, use the heuristic
|
|
747 // that a larger generation size means lower collection costs.
|
|
748 if (major_collection_estimator()->increment_will_decrease() ||
|
|
749 (_old_gen_change_for_major_throughput
|
|
750 <= AdaptiveSizePolicyInitializingSteps)) {
|
|
751 // Increase tenured generation size to reduce major collection cost
|
|
752 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
|
|
753 *desired_promo_size_ptr) {
|
|
754 *desired_promo_size_ptr = _promo_size + scaled_promo_heap_delta;
|
|
755 }
|
|
756 set_change_old_gen_for_throughput(
|
|
757 increase_old_gen_for_throughput_true);
|
|
758 _old_gen_change_for_major_throughput++;
|
|
759 } else {
|
|
760 // EXPERIMENTAL ADJUSTMENT
|
|
761 // Record that decreasing the old gen size would decrease
|
|
762 // the major collection cost but don't do it.
|
|
763 // *desired_promo_size_ptr = _promo_size -
|
|
764 // promo_decrement_aligned_down(*desired_promo_size_ptr);
|
|
765 set_change_old_gen_for_throughput(
|
|
766 decrease_old_gen_for_throughput_true);
|
|
767 }
|
|
768
|
|
769 break;
|
|
770 default:
|
|
771 // Simplest strategy
|
|
772 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
|
|
773 *desired_promo_size_ptr) {
|
|
774 *desired_promo_size_ptr = *desired_promo_size_ptr +
|
|
775 scaled_promo_heap_delta;
|
|
776 }
|
|
777 set_change_old_gen_for_throughput(
|
|
778 increase_old_gen_for_throughput_true);
|
|
779 _old_gen_change_for_major_throughput++;
|
|
780 }
|
|
781
|
|
782 if (PrintAdaptiveSizePolicy && Verbose) {
|
|
783 gclog_or_tty->print_cr(
|
|
784 "adjusting tenured gen for throughput (avg %f goal %f). "
|
|
785 "desired_promo_size " SIZE_FORMAT " promo_delta " SIZE_FORMAT ,
|
|
786 mutator_cost(), _throughput_goal,
|
|
787 *desired_promo_size_ptr, scaled_promo_heap_delta);
|
|
788 }
|
|
789 }
|
|
790
|
|
791 // Young generation
|
|
792 size_t scaled_eden_heap_delta = 0;
|
|
793 // Can the increment to the generation be scaled?
|
|
794 if (gc_cost() >= 0.0 && minor_gc_cost() >= 0.0) {
|
|
795 size_t eden_heap_delta =
|
|
796 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
|
|
797 double scale_by_ratio = minor_gc_cost() / gc_cost();
|
|
798 assert(scale_by_ratio <= 1.0 && scale_by_ratio >= 0.0, "Scaling is wrong");
|
|
799 scaled_eden_heap_delta =
|
|
800 (size_t) (scale_by_ratio * (double) eden_heap_delta);
|
|
801 if (PrintAdaptiveSizePolicy && Verbose) {
|
|
802 gclog_or_tty->print_cr(
|
|
803 "Scaled eden increment: " SIZE_FORMAT " by %f down to "
|
|
804 SIZE_FORMAT,
|
|
805 eden_heap_delta, scale_by_ratio, scaled_eden_heap_delta);
|
|
806 }
|
|
807 } else if (minor_gc_cost() >= 0.0) {
|
|
808 // Scaling is not going to work. If the minor gc time is the
|
|
809 // larger, give it a full increment.
|
|
810 if (minor_gc_cost() > major_gc_cost()) {
|
|
811 scaled_eden_heap_delta =
|
|
812 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
|
|
813 }
|
|
814 } else {
|
|
815 // Don't expect to get here but it's ok if it does
|
|
816 // in the product build since the delta will be 0
|
|
817 // and nothing will change.
|
|
818 assert(false, "Unexpected value for gc costs");
|
|
819 }
|
|
820
|
|
821 // Use a heuristic for some number of collections to give
|
|
822 // the averages time to settle down.
|
|
823 switch (AdaptiveSizeThroughPutPolicy) {
|
|
824 case 1:
|
|
825 if (minor_collection_estimator()->increment_will_decrease() ||
|
|
826 (_young_gen_change_for_minor_throughput
|
|
827 <= AdaptiveSizePolicyInitializingSteps)) {
|
|
828 // Expand young generation size to reduce frequency of
|
|
829 // of collections.
|
|
830 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
|
|
831 *desired_eden_size_ptr) {
|
|
832 *desired_eden_size_ptr =
|
|
833 *desired_eden_size_ptr + scaled_eden_heap_delta;
|
|
834 }
|
|
835 set_change_young_gen_for_throughput(
|
|
836 increase_young_gen_for_througput_true);
|
|
837 _young_gen_change_for_minor_throughput++;
|
|
838 } else {
|
|
839 // EXPERIMENTAL ADJUSTMENT
|
|
840 // Record that decreasing the young gen size would decrease
|
|
841 // the minor collection cost but don't do it.
|
|
842 // *desired_eden_size_ptr = _eden_size -
|
|
843 // eden_decrement_aligned_down(*desired_eden_size_ptr);
|
|
844 set_change_young_gen_for_throughput(
|
|
845 decrease_young_gen_for_througput_true);
|
|
846 }
|
|
847 break;
|
|
848 default:
|
|
849 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
|
|
850 *desired_eden_size_ptr) {
|
|
851 *desired_eden_size_ptr =
|
|
852 *desired_eden_size_ptr + scaled_eden_heap_delta;
|
|
853 }
|
|
854 set_change_young_gen_for_throughput(
|
|
855 increase_young_gen_for_througput_true);
|
|
856 _young_gen_change_for_minor_throughput++;
|
|
857 }
|
|
858
|
|
859 if (PrintAdaptiveSizePolicy && Verbose) {
|
|
860 gclog_or_tty->print_cr(
|
|
861 "adjusting eden for throughput (avg %f goal %f). desired_eden_size "
|
|
862 SIZE_FORMAT " eden delta " SIZE_FORMAT "\n",
|
|
863 mutator_cost(), _throughput_goal,
|
|
864 *desired_eden_size_ptr, scaled_eden_heap_delta);
|
|
865 }
|
|
866 }
|
|
867
|
|
868 size_t PSAdaptiveSizePolicy::adjust_promo_for_footprint(
|
|
869 size_t desired_promo_size, size_t desired_sum) {
|
|
870 assert(desired_promo_size <= desired_sum, "Inconsistent parameters");
|
|
871 set_decrease_for_footprint(decrease_old_gen_for_footprint_true);
|
|
872
|
|
873 size_t change = promo_decrement(desired_promo_size);
|
|
874 change = scale_down(change, desired_promo_size, desired_sum);
|
|
875
|
|
876 size_t reduced_size = desired_promo_size - change;
|
|
877
|
|
878 if (PrintAdaptiveSizePolicy && Verbose) {
|
|
879 gclog_or_tty->print_cr(
|
|
880 "AdaptiveSizePolicy::compute_generation_free_space "
|
|
881 "adjusting tenured gen for footprint. "
|
|
882 "starting promo size " SIZE_FORMAT
|
|
883 " reduced promo size " SIZE_FORMAT,
|
|
884 " promo delta " SIZE_FORMAT,
|
|
885 desired_promo_size, reduced_size, change );
|
|
886 }
|
|
887
|
|
888 assert(reduced_size <= desired_promo_size, "Inconsistent result");
|
|
889 return reduced_size;
|
|
890 }
|
|
891
|
|
892 size_t PSAdaptiveSizePolicy::adjust_eden_for_footprint(
|
|
893 size_t desired_eden_size, size_t desired_sum) {
|
|
894 assert(desired_eden_size <= desired_sum, "Inconsistent parameters");
|
|
895 set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
|
|
896
|
|
897 size_t change = eden_decrement(desired_eden_size);
|
|
898 change = scale_down(change, desired_eden_size, desired_sum);
|
|
899
|
|
900 size_t reduced_size = desired_eden_size - change;
|
|
901
|
|
902 if (PrintAdaptiveSizePolicy && Verbose) {
|
|
903 gclog_or_tty->print_cr(
|
|
904 "AdaptiveSizePolicy::compute_generation_free_space "
|
|
905 "adjusting eden for footprint. "
|
|
906 " starting eden size " SIZE_FORMAT
|
|
907 " reduced eden size " SIZE_FORMAT
|
|
908 " eden delta " SIZE_FORMAT,
|
|
909 desired_eden_size, reduced_size, change);
|
|
910 }
|
|
911
|
|
912 assert(reduced_size <= desired_eden_size, "Inconsistent result");
|
|
913 return reduced_size;
|
|
914 }
|
|
915
|
|
916 // Scale down "change" by the factor
|
|
917 // part / total
|
|
918 // Don't align the results.
|
|
919
|
|
920 size_t PSAdaptiveSizePolicy::scale_down(size_t change,
|
|
921 double part,
|
|
922 double total) {
|
|
923 assert(part <= total, "Inconsistent input");
|
|
924 size_t reduced_change = change;
|
|
925 if (total > 0) {
|
|
926 double fraction = part / total;
|
|
927 reduced_change = (size_t) (fraction * (double) change);
|
|
928 }
|
|
929 assert(reduced_change <= change, "Inconsistent result");
|
|
930 return reduced_change;
|
|
931 }
|
|
932
|
|
933 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden,
|
|
934 uint percent_change) {
|
|
935 size_t eden_heap_delta;
|
|
936 eden_heap_delta = cur_eden / 100 * percent_change;
|
|
937 return eden_heap_delta;
|
|
938 }
|
|
939
|
|
940 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden) {
|
|
941 return eden_increment(cur_eden, YoungGenerationSizeIncrement);
|
|
942 }
|
|
943
|
|
944 size_t PSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) {
|
|
945 size_t result = eden_increment(cur_eden, YoungGenerationSizeIncrement);
|
|
946 return align_size_up(result, _intra_generation_alignment);
|
|
947 }
|
|
948
|
|
949 size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) {
|
|
950 size_t result = eden_increment(cur_eden);
|
|
951 return align_size_down(result, _intra_generation_alignment);
|
|
952 }
|
|
953
|
|
954 size_t PSAdaptiveSizePolicy::eden_increment_with_supplement_aligned_up(
|
|
955 size_t cur_eden) {
|
|
956 size_t result = eden_increment(cur_eden,
|
|
957 YoungGenerationSizeIncrement + _young_gen_size_increment_supplement);
|
|
958 return align_size_up(result, _intra_generation_alignment);
|
|
959 }
|
|
960
|
|
961 size_t PSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) {
|
|
962 size_t eden_heap_delta = eden_decrement(cur_eden);
|
|
963 return align_size_down(eden_heap_delta, _intra_generation_alignment);
|
|
964 }
|
|
965
|
|
966 size_t PSAdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
|
|
967 size_t eden_heap_delta = eden_increment(cur_eden) /
|
|
968 AdaptiveSizeDecrementScaleFactor;
|
|
969 return eden_heap_delta;
|
|
970 }
|
|
971
|
|
972 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo,
|
|
973 uint percent_change) {
|
|
974 size_t promo_heap_delta;
|
|
975 promo_heap_delta = cur_promo / 100 * percent_change;
|
|
976 return promo_heap_delta;
|
|
977 }
|
|
978
|
|
979 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo) {
|
|
980 return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
|
|
981 }
|
|
982
|
|
983 size_t PSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) {
|
|
984 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
|
|
985 return align_size_up(result, _intra_generation_alignment);
|
|
986 }
|
|
987
|
|
988 size_t PSAdaptiveSizePolicy::promo_increment_aligned_down(size_t cur_promo) {
|
|
989 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
|
|
990 return align_size_down(result, _intra_generation_alignment);
|
|
991 }
|
|
992
|
|
993 size_t PSAdaptiveSizePolicy::promo_increment_with_supplement_aligned_up(
|
|
994 size_t cur_promo) {
|
|
995 size_t result = promo_increment(cur_promo,
|
|
996 TenuredGenerationSizeIncrement + _old_gen_size_increment_supplement);
|
|
997 return align_size_up(result, _intra_generation_alignment);
|
|
998 }
|
|
999
|
|
1000 size_t PSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) {
|
|
1001 size_t promo_heap_delta = promo_decrement(cur_promo);
|
|
1002 return align_size_down(promo_heap_delta, _intra_generation_alignment);
|
|
1003 }
|
|
1004
|
|
1005 size_t PSAdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
|
|
1006 size_t promo_heap_delta = promo_increment(cur_promo);
|
|
1007 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
|
|
1008 return promo_heap_delta;
|
|
1009 }
|
|
1010
|
|
1011 int PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold(
|
|
1012 bool is_survivor_overflow,
|
|
1013 int tenuring_threshold,
|
|
1014 size_t survivor_limit) {
|
|
1015 assert(survivor_limit >= _intra_generation_alignment,
|
|
1016 "survivor_limit too small");
|
|
1017 assert((size_t)align_size_down(survivor_limit, _intra_generation_alignment)
|
|
1018 == survivor_limit, "survivor_limit not aligned");
|
|
1019
|
|
1020 // This method is called even if the tenuring threshold and survivor
|
|
1021 // spaces are not adjusted so that the averages are sampled above.
|
|
1022 if (!UsePSAdaptiveSurvivorSizePolicy ||
|
|
1023 !young_gen_policy_is_ready()) {
|
|
1024 return tenuring_threshold;
|
|
1025 }
|
|
1026
|
|
1027 // We'll decide whether to increase or decrease the tenuring
|
|
1028 // threshold based partly on the newly computed survivor size
|
|
1029 // (if we hit the maximum limit allowed, we'll always choose to
|
|
1030 // decrement the threshold).
|
|
1031 bool incr_tenuring_threshold = false;
|
|
1032 bool decr_tenuring_threshold = false;
|
|
1033
|
|
1034 set_decrement_tenuring_threshold_for_gc_cost(false);
|
|
1035 set_increment_tenuring_threshold_for_gc_cost(false);
|
|
1036 set_decrement_tenuring_threshold_for_survivor_limit(false);
|
|
1037
|
|
1038 if (!is_survivor_overflow) {
|
|
1039 // Keep running averages on how much survived
|
|
1040
|
|
1041 // We use the tenuring threshold to equalize the cost of major
|
|
1042 // and minor collections.
|
|
1043 // ThresholdTolerance is used to indicate how sensitive the
|
|
1044 // tenuring threshold is to differences in cost betweent the
|
|
1045 // collection types.
|
|
1046
|
|
1047 // Get the times of interest. This involves a little work, so
|
|
1048 // we cache the values here.
|
|
1049 const double major_cost = major_gc_cost();
|
|
1050 const double minor_cost = minor_gc_cost();
|
|
1051
|
|
1052 if (minor_cost > major_cost * _threshold_tolerance_percent) {
|
|
1053 // Minor times are getting too long; lower the threshold so
|
|
1054 // less survives and more is promoted.
|
|
1055 decr_tenuring_threshold = true;
|
|
1056 set_decrement_tenuring_threshold_for_gc_cost(true);
|
|
1057 } else if (major_cost > minor_cost * _threshold_tolerance_percent) {
|
|
1058 // Major times are too long, so we want less promotion.
|
|
1059 incr_tenuring_threshold = true;
|
|
1060 set_increment_tenuring_threshold_for_gc_cost(true);
|
|
1061 }
|
|
1062
|
|
1063 } else {
|
|
1064 // Survivor space overflow occurred, so promoted and survived are
|
|
1065 // not accurate. We'll make our best guess by combining survived
|
|
1066 // and promoted and count them as survivors.
|
|
1067 //
|
|
1068 // We'll lower the tenuring threshold to see if we can correct
|
|
1069 // things. Also, set the survivor size conservatively. We're
|
|
1070 // trying to avoid many overflows from occurring if defnew size
|
|
1071 // is just too small.
|
|
1072
|
|
1073 decr_tenuring_threshold = true;
|
|
1074 }
|
|
1075
|
|
1076 // The padded average also maintains a deviation from the average;
|
|
1077 // we use this to see how good of an estimate we have of what survived.
|
|
1078 // We're trying to pad the survivor size as little as possible without
|
|
1079 // overflowing the survivor spaces.
|
|
1080 size_t target_size = align_size_up((size_t)_avg_survived->padded_average(),
|
|
1081 _intra_generation_alignment);
|
|
1082 target_size = MAX2(target_size, _intra_generation_alignment);
|
|
1083
|
|
1084 if (target_size > survivor_limit) {
|
|
1085 // Target size is bigger than we can handle. Let's also reduce
|
|
1086 // the tenuring threshold.
|
|
1087 target_size = survivor_limit;
|
|
1088 decr_tenuring_threshold = true;
|
|
1089 set_decrement_tenuring_threshold_for_survivor_limit(true);
|
|
1090 }
|
|
1091
|
|
1092 // Finally, increment or decrement the tenuring threshold, as decided above.
|
|
1093 // We test for decrementing first, as we might have hit the target size
|
|
1094 // limit.
|
|
1095 if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
|
|
1096 if (tenuring_threshold > 1) {
|
|
1097 tenuring_threshold--;
|
|
1098 }
|
|
1099 } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
|
|
1100 if (tenuring_threshold < MaxTenuringThreshold) {
|
|
1101 tenuring_threshold++;
|
|
1102 }
|
|
1103 }
|
|
1104
|
|
1105 // We keep a running average of the amount promoted which is used
|
|
1106 // to decide when we should collect the old generation (when
|
|
1107 // the amount of old gen free space is less than what we expect to
|
|
1108 // promote).
|
|
1109
|
|
1110 if (PrintAdaptiveSizePolicy) {
|
|
1111 // A little more detail if Verbose is on
|
|
1112 if (Verbose) {
|
|
1113 gclog_or_tty->print( " avg_survived: %f"
|
|
1114 " avg_deviation: %f",
|
|
1115 _avg_survived->average(),
|
|
1116 _avg_survived->deviation());
|
|
1117 }
|
|
1118
|
|
1119 gclog_or_tty->print( " avg_survived_padded_avg: %f",
|
|
1120 _avg_survived->padded_average());
|
|
1121
|
|
1122 if (Verbose) {
|
|
1123 gclog_or_tty->print( " avg_promoted_avg: %f"
|
|
1124 " avg_promoted_dev: %f",
|
|
1125 avg_promoted()->average(),
|
|
1126 avg_promoted()->deviation());
|
|
1127 }
|
|
1128
|
|
1129 gclog_or_tty->print( " avg_promoted_padded_avg: %f"
|
|
1130 " avg_pretenured_padded_avg: %f"
|
|
1131 " tenuring_thresh: %d"
|
|
1132 " target_size: " SIZE_FORMAT,
|
|
1133 avg_promoted()->padded_average(),
|
|
1134 _avg_pretenured->padded_average(),
|
|
1135 tenuring_threshold, target_size);
|
|
1136 tty->cr();
|
|
1137 }
|
|
1138
|
|
1139 set_survivor_size(target_size);
|
|
1140
|
|
1141 return tenuring_threshold;
|
|
1142 }
|
|
1143
|
|
1144 void PSAdaptiveSizePolicy::update_averages(bool is_survivor_overflow,
|
|
1145 size_t survived,
|
|
1146 size_t promoted) {
|
|
1147 // Update averages
|
|
1148 if (!is_survivor_overflow) {
|
|
1149 // Keep running averages on how much survived
|
|
1150 _avg_survived->sample(survived);
|
|
1151 } else {
|
|
1152 size_t survived_guess = survived + promoted;
|
|
1153 _avg_survived->sample(survived_guess);
|
|
1154 }
|
|
1155 avg_promoted()->sample(promoted + _avg_pretenured->padded_average());
|
|
1156
|
|
1157 if (PrintAdaptiveSizePolicy) {
|
|
1158 gclog_or_tty->print(
|
|
1159 "AdaptiveSizePolicy::compute_survivor_space_size_and_thresh:"
|
|
1160 " survived: " SIZE_FORMAT
|
|
1161 " promoted: " SIZE_FORMAT
|
|
1162 " overflow: %s",
|
|
1163 survived, promoted, is_survivor_overflow ? "true" : "false");
|
|
1164 }
|
|
1165 }
|
|
1166
|
|
1167 bool PSAdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st)
|
|
1168 const {
|
|
1169
|
|
1170 if (!UseAdaptiveSizePolicy) return false;
|
|
1171
|
|
1172 return AdaptiveSizePolicy::print_adaptive_size_policy_on(
|
|
1173 st,
|
|
1174 PSScavenge::tenuring_threshold());
|
|
1175 }
|