0
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1 /*
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2 * Copyright 1999-2007 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 // Thread-Local Edens support
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26
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27 # include "incls/_precompiled.incl"
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28 # include "incls/_threadLocalAllocBuffer.cpp.incl"
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29
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30 // static member initialization
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31 unsigned ThreadLocalAllocBuffer::_target_refills = 0;
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32 GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats = NULL;
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33
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34 void ThreadLocalAllocBuffer::clear_before_allocation() {
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35 _slow_refill_waste += (unsigned)remaining();
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36 make_parsable(true); // also retire the TLAB
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37 }
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38
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39 void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
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40 global_stats()->initialize();
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41
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42 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
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43 thread->tlab().accumulate_statistics();
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44 thread->tlab().initialize_statistics();
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45 }
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46
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47 // Publish new stats if some allocation occurred.
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48 if (global_stats()->allocation() != 0) {
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49 global_stats()->publish();
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50 if (PrintTLAB) {
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51 global_stats()->print();
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52 }
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53 }
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54 }
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55
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56 void ThreadLocalAllocBuffer::accumulate_statistics() {
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57 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize;
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58 size_t unused = Universe::heap()->unsafe_max_tlab_alloc(myThread()) / HeapWordSize;
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59 size_t used = capacity - unused;
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60
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61 // Update allocation history if a reasonable amount of eden was allocated.
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62 bool update_allocation_history = used > 0.5 * capacity;
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63
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64 _gc_waste += (unsigned)remaining();
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65
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66 if (PrintTLAB && (_number_of_refills > 0 || Verbose)) {
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67 print_stats("gc");
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68 }
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69
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70 if (_number_of_refills > 0) {
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71
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72 if (update_allocation_history) {
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73 // Average the fraction of eden allocated in a tlab by this
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74 // thread for use in the next resize operation.
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75 // _gc_waste is not subtracted because it's included in
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76 // "used".
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77 size_t allocation = _number_of_refills * desired_size();
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78 double alloc_frac = allocation / (double) used;
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79 _allocation_fraction.sample(alloc_frac);
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80 }
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81 global_stats()->update_allocating_threads();
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82 global_stats()->update_number_of_refills(_number_of_refills);
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83 global_stats()->update_allocation(_number_of_refills * desired_size());
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84 global_stats()->update_gc_waste(_gc_waste);
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85 global_stats()->update_slow_refill_waste(_slow_refill_waste);
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86 global_stats()->update_fast_refill_waste(_fast_refill_waste);
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87
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88 } else {
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89 assert(_number_of_refills == 0 && _fast_refill_waste == 0 &&
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90 _slow_refill_waste == 0 && _gc_waste == 0,
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91 "tlab stats == 0");
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92 }
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93 global_stats()->update_slow_allocations(_slow_allocations);
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94 }
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95
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96 // Fills the current tlab with a dummy filler array to create
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97 // an illusion of a contiguous Eden and optionally retires the tlab.
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98 // Waste accounting should be done in caller as appropriate; see,
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99 // for example, clear_before_allocation().
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100 void ThreadLocalAllocBuffer::make_parsable(bool retire) {
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101 if (end() != NULL) {
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102 invariants();
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103 MemRegion mr(top(), hard_end());
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104 SharedHeap::fill_region_with_object(mr);
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105
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106 if (retire || ZeroTLAB) { // "Reset" the TLAB
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107 set_start(NULL);
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108 set_top(NULL);
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109 set_pf_top(NULL);
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110 set_end(NULL);
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111 }
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112 }
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113 assert(!(retire || ZeroTLAB) ||
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114 (start() == NULL && end() == NULL && top() == NULL),
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115 "TLAB must be reset");
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116 }
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117
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118 void ThreadLocalAllocBuffer::resize_all_tlabs() {
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119 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
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120 thread->tlab().resize();
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121 }
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122 }
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123
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124 void ThreadLocalAllocBuffer::resize() {
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125
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126 if (ResizeTLAB) {
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127 // Compute the next tlab size using expected allocation amount
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128 size_t alloc = (size_t)(_allocation_fraction.average() *
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129 (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize));
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130 size_t new_size = alloc / _target_refills;
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131
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132 new_size = MIN2(MAX2(new_size, min_size()), max_size());
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133
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134 size_t aligned_new_size = align_object_size(new_size);
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135
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136 if (PrintTLAB && Verbose) {
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137 gclog_or_tty->print("TLAB new size: thread: " INTPTR_FORMAT " [id: %2d]"
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138 " refills %d alloc: %8.6f desired_size: " SIZE_FORMAT " -> " SIZE_FORMAT "\n",
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139 myThread(), myThread()->osthread()->thread_id(),
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140 _target_refills, _allocation_fraction.average(), desired_size(), aligned_new_size);
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141 }
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142 set_desired_size(aligned_new_size);
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143
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144 set_refill_waste_limit(initial_refill_waste_limit());
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145 }
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146 }
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147
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148 void ThreadLocalAllocBuffer::initialize_statistics() {
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149 _number_of_refills = 0;
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150 _fast_refill_waste = 0;
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151 _slow_refill_waste = 0;
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152 _gc_waste = 0;
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153 _slow_allocations = 0;
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154 }
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155
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156 void ThreadLocalAllocBuffer::fill(HeapWord* start,
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157 HeapWord* top,
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158 size_t new_size) {
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159 _number_of_refills++;
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160 if (PrintTLAB && Verbose) {
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161 print_stats("fill");
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162 }
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163 assert(top <= start + new_size - alignment_reserve(), "size too small");
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164 initialize(start, top, start + new_size - alignment_reserve());
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165
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166 // Reset amount of internal fragmentation
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167 set_refill_waste_limit(initial_refill_waste_limit());
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168 }
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169
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170 void ThreadLocalAllocBuffer::initialize(HeapWord* start,
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171 HeapWord* top,
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172 HeapWord* end) {
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173 set_start(start);
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174 set_top(top);
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175 set_pf_top(top);
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176 set_end(end);
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177 invariants();
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178 }
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179
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180 void ThreadLocalAllocBuffer::initialize() {
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181 initialize(NULL, // start
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182 NULL, // top
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183 NULL); // end
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184
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185 set_desired_size(initial_desired_size());
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186
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187 // Following check is needed because at startup the main (primordial)
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188 // thread is initialized before the heap is. The initialization for
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189 // this thread is redone in startup_initialization below.
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190 if (Universe::heap() != NULL) {
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191 size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize;
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192 double alloc_frac = desired_size() * target_refills() / (double) capacity;
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193 _allocation_fraction.sample(alloc_frac);
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194 }
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195
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196 set_refill_waste_limit(initial_refill_waste_limit());
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197
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198 initialize_statistics();
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199 }
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200
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201 void ThreadLocalAllocBuffer::startup_initialization() {
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202
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203 // Assuming each thread's active tlab is, on average,
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204 // 1/2 full at a GC
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205 _target_refills = 100 / (2 * TLABWasteTargetPercent);
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206 _target_refills = MAX2(_target_refills, (unsigned)1U);
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207
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208 _global_stats = new GlobalTLABStats();
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209
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210 // During jvm startup, the main (primordial) thread is initialized
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211 // before the heap is initialized. So reinitialize it now.
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212 guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread");
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213 Thread::current()->tlab().initialize();
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214
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215 if (PrintTLAB && Verbose) {
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216 gclog_or_tty->print("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT "\n",
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217 min_size(), Thread::current()->tlab().initial_desired_size(), max_size());
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218 }
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219 }
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220
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221 size_t ThreadLocalAllocBuffer::initial_desired_size() {
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222 size_t init_sz;
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223
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224 if (TLABSize > 0) {
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225 init_sz = MIN2(TLABSize / HeapWordSize, max_size());
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226 } else if (global_stats() == NULL) {
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227 // Startup issue - main thread initialized before heap initialized.
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228 init_sz = min_size();
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229 } else {
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230 // Initial size is a function of the average number of allocating threads.
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231 unsigned nof_threads = global_stats()->allocating_threads_avg();
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232
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233 init_sz = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) /
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234 (nof_threads * target_refills());
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235 init_sz = align_object_size(init_sz);
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236 init_sz = MIN2(MAX2(init_sz, min_size()), max_size());
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237 }
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238 return init_sz;
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239 }
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240
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241 const size_t ThreadLocalAllocBuffer::max_size() {
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242
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243 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
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244 // This restriction could be removed by enabling filling with multiple arrays.
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245 // If we compute that the reasonable way as
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246 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
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247 // we'll overflow on the multiply, so we do the divide first.
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248 // We actually lose a little by dividing first,
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249 // but that just makes the TLAB somewhat smaller than the biggest array,
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250 // which is fine, since we'll be able to fill that.
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251
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252 size_t unaligned_max_size = typeArrayOopDesc::header_size(T_INT) +
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253 sizeof(jint) *
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254 ((juint) max_jint / (size_t) HeapWordSize);
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255 return align_size_down(unaligned_max_size, MinObjAlignment);
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256 }
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257
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258 void ThreadLocalAllocBuffer::print_stats(const char* tag) {
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259 Thread* thrd = myThread();
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260 size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste;
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261 size_t alloc = _number_of_refills * _desired_size;
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262 double waste_percent = alloc == 0 ? 0.0 :
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263 100.0 * waste / alloc;
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264 size_t tlab_used = Universe::heap()->tlab_capacity(thrd) -
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265 Universe::heap()->unsafe_max_tlab_alloc(thrd);
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266 gclog_or_tty->print("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]"
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267 " desired_size: " SIZE_FORMAT "KB"
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268 " slow allocs: %d refill waste: " SIZE_FORMAT "B"
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269 " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB"
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270 " slow: %dB fast: %dB\n",
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271 tag, thrd, thrd->osthread()->thread_id(),
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272 _desired_size / (K / HeapWordSize),
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273 _slow_allocations, _refill_waste_limit * HeapWordSize,
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274 _allocation_fraction.average(),
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275 _allocation_fraction.average() * tlab_used / K,
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276 _number_of_refills, waste_percent,
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277 _gc_waste * HeapWordSize,
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278 _slow_refill_waste * HeapWordSize,
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279 _fast_refill_waste * HeapWordSize);
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280 }
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281
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282 void ThreadLocalAllocBuffer::verify() {
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283 HeapWord* p = start();
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284 HeapWord* t = top();
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285 HeapWord* prev_p = NULL;
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286 while (p < t) {
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287 oop(p)->verify();
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288 prev_p = p;
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289 p += oop(p)->size();
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290 }
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291 guarantee(p == top(), "end of last object must match end of space");
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292 }
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293
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294 Thread* ThreadLocalAllocBuffer::myThread() {
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295 return (Thread*)(((char *)this) +
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296 in_bytes(start_offset()) -
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297 in_bytes(Thread::tlab_start_offset()));
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298 }
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299
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300
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301 GlobalTLABStats::GlobalTLABStats() :
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302 _allocating_threads_avg(TLABAllocationWeight) {
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303
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304 initialize();
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305
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306 _allocating_threads_avg.sample(1); // One allocating thread at startup
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307
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308 if (UsePerfData) {
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309
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310 EXCEPTION_MARK;
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311 ResourceMark rm;
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312
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313 char* cname = PerfDataManager::counter_name("tlab", "allocThreads");
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314 _perf_allocating_threads =
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315 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
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316
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317 cname = PerfDataManager::counter_name("tlab", "fills");
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318 _perf_total_refills =
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319 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
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320
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321 cname = PerfDataManager::counter_name("tlab", "maxFills");
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322 _perf_max_refills =
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323 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
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324
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325 cname = PerfDataManager::counter_name("tlab", "alloc");
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326 _perf_allocation =
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327 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
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328
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329 cname = PerfDataManager::counter_name("tlab", "gcWaste");
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330 _perf_gc_waste =
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331 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
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332
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333 cname = PerfDataManager::counter_name("tlab", "maxGcWaste");
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334 _perf_max_gc_waste =
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335 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
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336
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337 cname = PerfDataManager::counter_name("tlab", "slowWaste");
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338 _perf_slow_refill_waste =
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339 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
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340
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341 cname = PerfDataManager::counter_name("tlab", "maxSlowWaste");
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342 _perf_max_slow_refill_waste =
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343 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
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344
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345 cname = PerfDataManager::counter_name("tlab", "fastWaste");
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346 _perf_fast_refill_waste =
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347 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
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348
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349 cname = PerfDataManager::counter_name("tlab", "maxFastWaste");
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350 _perf_max_fast_refill_waste =
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351 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK);
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352
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353 cname = PerfDataManager::counter_name("tlab", "slowAlloc");
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354 _perf_slow_allocations =
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355 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
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356
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357 cname = PerfDataManager::counter_name("tlab", "maxSlowAlloc");
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358 _perf_max_slow_allocations =
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359 PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK);
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360 }
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361 }
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362
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363 void GlobalTLABStats::initialize() {
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364 // Clear counters summarizing info from all threads
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365 _allocating_threads = 0;
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366 _total_refills = 0;
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367 _max_refills = 0;
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368 _total_allocation = 0;
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369 _total_gc_waste = 0;
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370 _max_gc_waste = 0;
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371 _total_slow_refill_waste = 0;
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372 _max_slow_refill_waste = 0;
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373 _total_fast_refill_waste = 0;
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374 _max_fast_refill_waste = 0;
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375 _total_slow_allocations = 0;
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376 _max_slow_allocations = 0;
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377 }
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378
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379 void GlobalTLABStats::publish() {
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380 _allocating_threads_avg.sample(_allocating_threads);
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381 if (UsePerfData) {
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382 _perf_allocating_threads ->set_value(_allocating_threads);
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383 _perf_total_refills ->set_value(_total_refills);
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384 _perf_max_refills ->set_value(_max_refills);
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385 _perf_allocation ->set_value(_total_allocation);
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386 _perf_gc_waste ->set_value(_total_gc_waste);
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387 _perf_max_gc_waste ->set_value(_max_gc_waste);
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388 _perf_slow_refill_waste ->set_value(_total_slow_refill_waste);
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389 _perf_max_slow_refill_waste->set_value(_max_slow_refill_waste);
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390 _perf_fast_refill_waste ->set_value(_total_fast_refill_waste);
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391 _perf_max_fast_refill_waste->set_value(_max_fast_refill_waste);
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392 _perf_slow_allocations ->set_value(_total_slow_allocations);
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393 _perf_max_slow_allocations ->set_value(_max_slow_allocations);
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394 }
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395 }
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396
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397 void GlobalTLABStats::print() {
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398 size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste;
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399 double waste_percent = _total_allocation == 0 ? 0.0 :
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400 100.0 * waste / _total_allocation;
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401 gclog_or_tty->print("TLAB totals: thrds: %d refills: %d max: %d"
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402 " slow allocs: %d max %d waste: %4.1f%%"
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403 " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"
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404 " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B"
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405 " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B\n",
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406 _allocating_threads,
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407 _total_refills, _max_refills,
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408 _total_slow_allocations, _max_slow_allocations,
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409 waste_percent,
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410 _total_gc_waste * HeapWordSize,
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411 _max_gc_waste * HeapWordSize,
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412 _total_slow_refill_waste * HeapWordSize,
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413 _max_slow_refill_waste * HeapWordSize,
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414 _total_fast_refill_waste * HeapWordSize,
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415 _max_fast_refill_waste * HeapWordSize);
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416 }
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