1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "interpreter/invocationCounter.hpp"
  27 #include "runtime/frame.hpp"
  28 #include "runtime/handles.inline.hpp"
  29 
  30 
  31 // Implementation of InvocationCounter
  32 
  33 void InvocationCounter::init() {
  34   _counter = 0;  // reset all the bits, including the sticky carry
  35   reset();
  36 }
  37 
  38 void InvocationCounter::reset() {
  39   // Only reset the state and don't make the method look like it's never
  40   // been executed
  41   set_state(wait_for_compile);
  42 }
  43 
  44 void InvocationCounter::set_carry() {
  45   set_carry_flag();
  46   // The carry bit now indicates that this counter had achieved a very
  47   // large value.  Now reduce the value, so that the method can be
  48   // executed many more times before re-entering the VM.
  49   int old_count = count();
  50   int new_count = MIN2(old_count, (int) (CompileThreshold / 2));
  51   // prevent from going to zero, to distinguish from never-executed methods
  52   if (new_count == 0)  new_count = 1;
  53   if (old_count != new_count)  set(state(), new_count);
  54 }
  55 
  56 void InvocationCounter::set_state(State state) {
  57   assert(0 <= state && state < number_of_states, "illegal state");
  58   int init = _init[state];
  59   // prevent from going to zero, to distinguish from never-executed methods
  60   if (init == 0 && count() > 0)  init = 1;
  61   int carry = (_counter & carry_mask);    // the carry bit is sticky
  62   _counter = (init << number_of_noncount_bits) | carry | state;
  63 }
  64 
  65 
  66 void InvocationCounter::print() {
  67   tty->print_cr("invocation count: up = %d, limit = %d, carry = %s, state = %s",
  68                                    count(), limit(),
  69                                    carry() ? "true" : "false",
  70                                    state_as_string(state()));
  71 }
  72 
  73 void InvocationCounter::print_short() {
  74   tty->print(" [%d%s;%s]", count(), carry()?"+carry":"", state_as_short_string(state()));
  75 }
  76 
  77 // Initialization
  78 
  79 int                       InvocationCounter::_init  [InvocationCounter::number_of_states];
  80 InvocationCounter::Action InvocationCounter::_action[InvocationCounter::number_of_states];
  81 int                       InvocationCounter::InterpreterInvocationLimit;
  82 int                       InvocationCounter::InterpreterBackwardBranchLimit;
  83 int                       InvocationCounter::InterpreterProfileLimit;
  84 
  85 
  86 const char* InvocationCounter::state_as_string(State state) {
  87   switch (state) {
  88     case wait_for_nothing            : return "wait_for_nothing";
  89     case wait_for_compile            : return "wait_for_compile";
  90   }
  91   ShouldNotReachHere();
  92   return NULL;
  93 }
  94 
  95 const char* InvocationCounter::state_as_short_string(State state) {
  96   switch (state) {
  97     case wait_for_nothing            : return "not comp.";
  98     case wait_for_compile            : return "compileable";
  99   }
 100   ShouldNotReachHere();
 101   return NULL;
 102 }
 103 
 104 
 105 static address do_nothing(methodHandle method, TRAPS) {
 106   // dummy action for inactive invocation counters
 107   MethodCounters* mcs = method->method_counters();
 108   assert(mcs != NULL, "");
 109   mcs->invocation_counter()->set_carry();
 110   mcs->invocation_counter()->set_state(InvocationCounter::wait_for_nothing);
 111   return NULL;
 112 }
 113 
 114 
 115 static address do_decay(methodHandle method, TRAPS) {
 116   // decay invocation counters so compilation gets delayed
 117   MethodCounters* mcs = method->method_counters();
 118   assert(mcs != NULL, "");
 119   mcs->invocation_counter()->decay();
 120   return NULL;
 121 }
 122 
 123 
 124 void InvocationCounter::def(State state, int init, Action action) {
 125   assert(0 <= state && state < number_of_states, "illegal state");
 126   assert(0 <= init  && init  < count_limit, "initial value out of range");
 127   _init  [state] = init;
 128   _action[state] = action;
 129 }
 130 
 131 address dummy_invocation_counter_overflow(methodHandle m, TRAPS) {
 132   ShouldNotReachHere();
 133   return NULL;
 134 }
 135 
 136 void InvocationCounter::reinitialize(bool delay_overflow) {
 137   // define states
 138   guarantee((int)number_of_states <= (int)state_limit, "adjust number_of_state_bits");
 139   def(wait_for_nothing, 0, do_nothing);
 140   if (delay_overflow) {
 141     def(wait_for_compile, 0, do_decay);
 142   } else {
 143     def(wait_for_compile, 0, dummy_invocation_counter_overflow);
 144   }
 145 
 146   InterpreterInvocationLimit = CompileThreshold << number_of_noncount_bits;
 147   InterpreterProfileLimit = ((CompileThreshold * InterpreterProfilePercentage) / 100)<< number_of_noncount_bits;
 148 
 149   // When methodData is collected, the backward branch limit is compared against a
 150   // methodData counter, rather than an InvocationCounter.  In the former case, we
 151   // don't need the shift by number_of_noncount_bits, but we do need to adjust
 152   // the factor by which we scale the threshold.
 153   if (ProfileInterpreter) {
 154     InterpreterBackwardBranchLimit = (CompileThreshold * (OnStackReplacePercentage - InterpreterProfilePercentage)) / 100;
 155   } else {
 156     InterpreterBackwardBranchLimit = ((CompileThreshold * OnStackReplacePercentage) / 100) << number_of_noncount_bits;
 157   }
 158 
 159   assert(0 <= InterpreterBackwardBranchLimit,
 160          "OSR threshold should be non-negative");
 161   assert(0 <= InterpreterProfileLimit &&
 162          InterpreterProfileLimit <= InterpreterInvocationLimit,
 163          "profile threshold should be less than the compilation threshold "
 164          "and non-negative");
 165 }
 166 
 167 void invocationCounter_init() {
 168   InvocationCounter::reinitialize(DelayCompilationDuringStartup);
 169 }