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1 /* |
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2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 #ifndef SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP |
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26 #define SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP |
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27 |
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28 #include "memory/allocation.hpp" |
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29 #include "runtime/handles.hpp" |
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30 #include "utilities/exceptions.hpp" |
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31 |
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32 // InvocationCounters are used to trigger actions when a limit (threshold) is reached. |
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33 // For different states, different limits and actions can be defined in the initialization |
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34 // routine of InvocationCounters. |
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35 // |
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36 // Implementation notes: For space reasons, state & counter are both encoded in one word, |
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37 // The state is encoded using some of the least significant bits, the counter is using the |
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38 // more significant bits. The counter is incremented before a method is activated and an |
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39 // action is triggered when when count() > limit(). |
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40 |
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41 class InvocationCounter VALUE_OBJ_CLASS_SPEC { |
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42 friend class VMStructs; |
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43 friend class ciReplay; |
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44 private: // bit no: |31 3| 2 | 1 0 | |
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45 unsigned int _counter; // format: [count|carry|state] |
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46 |
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47 enum PrivateConstants { |
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48 number_of_state_bits = 2, |
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49 number_of_carry_bits = 1, |
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50 number_of_noncount_bits = number_of_state_bits + number_of_carry_bits, |
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51 number_of_count_bits = BitsPerInt - number_of_noncount_bits, |
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52 state_limit = nth_bit(number_of_state_bits), |
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53 count_grain = nth_bit(number_of_state_bits + number_of_carry_bits), |
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54 carry_mask = right_n_bits(number_of_carry_bits) << number_of_state_bits, |
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55 state_mask = right_n_bits(number_of_state_bits), |
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56 status_mask = right_n_bits(number_of_state_bits + number_of_carry_bits), |
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57 count_mask = ((int)(-1) ^ status_mask) |
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58 }; |
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59 |
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60 public: |
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61 static int InterpreterInvocationLimit; // CompileThreshold scaled for interpreter use |
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62 static int InterpreterBackwardBranchLimit; // A separate threshold for on stack replacement |
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63 static int InterpreterProfileLimit; // Profiling threshold scaled for interpreter use |
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64 |
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65 typedef address (*Action)(methodHandle method, TRAPS); |
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66 |
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67 enum PublicConstants { |
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68 count_increment = count_grain, // use this value to increment the 32bit _counter word |
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69 count_mask_value = count_mask, // use this value to mask the backedge counter |
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70 count_shift = number_of_noncount_bits, |
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71 count_limit = nth_bit(number_of_count_bits - 1) |
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72 }; |
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73 |
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74 enum State { |
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75 wait_for_nothing, // do nothing when count() > limit() |
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76 wait_for_compile, // introduce nmethod when count() > limit() |
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77 number_of_states // must be <= state_limit |
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78 }; |
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79 |
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80 // Manipulation |
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81 void reset(); // sets state to wait state |
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82 void init(); // sets state into original state |
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83 void set_state(State state); // sets state and initializes counter correspondingly |
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84 inline void set(State state, int count); // sets state and counter |
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85 inline void decay(); // decay counter (divide by two) |
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86 void set_carry(); // set the sticky carry bit |
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87 void set_carry_flag() { _counter |= carry_mask; } |
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88 |
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89 int raw_counter() { return _counter; } |
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90 |
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91 // Accessors |
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92 State state() const { return (State)(_counter & state_mask); } |
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93 bool carry() const { return (_counter & carry_mask) != 0; } |
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94 int limit() const { return CompileThreshold; } |
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95 Action action() const { return _action[state()]; } |
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96 int count() const { return _counter >> number_of_noncount_bits; } |
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97 |
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98 int get_InvocationLimit() const { return InterpreterInvocationLimit >> number_of_noncount_bits; } |
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99 int get_BackwardBranchLimit() const { return InterpreterBackwardBranchLimit >> number_of_noncount_bits; } |
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100 int get_ProfileLimit() const { return InterpreterProfileLimit >> number_of_noncount_bits; } |
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101 |
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102 #ifdef CC_INTERP |
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103 // Test counter using scaled limits like the asm interpreter would do rather than doing |
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104 // the shifts to normalize the counter. |
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105 // Checks sum of invocation_counter and backedge_counter as the template interpreter does. |
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106 bool reached_InvocationLimit(InvocationCounter *back_edge_count) const { |
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107 return (_counter & count_mask) + (back_edge_count->_counter & count_mask) >= |
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108 (unsigned int) InterpreterInvocationLimit; |
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109 } |
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110 bool reached_BackwardBranchLimit(InvocationCounter *back_edge_count) const { |
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111 return (_counter & count_mask) + (back_edge_count->_counter & count_mask) >= |
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112 (unsigned int) InterpreterBackwardBranchLimit; |
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113 } |
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114 // Do this just like asm interpreter does for max speed. |
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115 bool reached_ProfileLimit(InvocationCounter *back_edge_count) const { |
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116 return (_counter & count_mask) + (back_edge_count->_counter & count_mask) >= |
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117 (unsigned int) InterpreterProfileLimit; |
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118 } |
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119 #endif // CC_INTERP |
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120 |
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121 void increment() { _counter += count_increment; } |
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122 |
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123 |
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124 // Printing |
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125 void print(); |
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126 void print_short(); |
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127 |
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128 // Miscellaneous |
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129 static ByteSize counter_offset() { return byte_offset_of(InvocationCounter, _counter); } |
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130 static void reinitialize(bool delay_overflow); |
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131 |
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132 private: |
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133 static int _init [number_of_states]; // the counter limits |
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134 static Action _action[number_of_states]; // the actions |
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135 |
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136 static void def(State state, int init, Action action); |
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137 static const char* state_as_string(State state); |
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138 static const char* state_as_short_string(State state); |
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139 }; |
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140 |
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141 inline void InvocationCounter::set(State state, int count) { |
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142 assert(0 <= state && state < number_of_states, "illegal state"); |
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143 int carry = (_counter & carry_mask); // the carry bit is sticky |
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144 _counter = (count << number_of_noncount_bits) | carry | state; |
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145 } |
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146 |
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147 inline void InvocationCounter::decay() { |
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148 int c = count(); |
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149 int new_count = c >> 1; |
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150 // prevent from going to zero, to distinguish from never-executed methods |
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151 if (c > 0 && new_count == 0) new_count = 1; |
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152 set(state(), new_count); |
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153 } |
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154 |
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155 |
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156 #endif // SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP |