*** old/src/share/vm/interpreter/invocationCounter.cpp	Wed Sep 17 15:59:02 2014
--- new/src/share/vm/interpreter/invocationCounter.cpp	Wed Sep 17 15:59:02 2014

*** 30,150 ****
--- 30,98 ----
  
  // Implementation of InvocationCounter
  
  void InvocationCounter::init() {
    _counter = 0;  // reset all the bits, including the sticky carry
    reset();
  }
  
  void InvocationCounter::reset() {
    // Only reset the state and don't make the method look like it's never
    // been executed
    set_state(wait_for_compile);
+   uint counter = raw_counter();
+   int init = 0;
+   // prevent from going to zero, to distinguish from never-executed methods
+   if (count(counter) > 0) {
+     init = 1;
+   }
+   counter = (init << number_of_noncount_bits) | (counter & carry_mask);
+   set_raw(counter);
  }
  
! void InvocationCounter::set_carry_and_reduce() {
    set_carry_flag();
    // The carry bit now indicates that this counter had achieved a very
    // large value.  Now reduce the value, so that the method can be
    // executed many more times before re-entering the VM.
!   int old_count = count();
+   // single read
+   uint counter = raw_counter();
+ 
+   //update
!   set_carry_flag(&counter);
+   int old_count = count(counter);
    int new_count = MIN2(old_count, (int) (CompileThreshold / 2));
    // prevent from going to zero, to distinguish from never-executed methods
!   if (new_count == 0)  new_count = 1;
!   if (old_count != new_count)  set(state(), new_count);
! }
!   if (new_count == 0) {
!     new_count = 1;
!   }
+   if (old_count != new_count) {
+     set_count(&counter, new_count);
+   }
  
  void InvocationCounter::set_state(State state) {
!   assert(0 <= state && state < number_of_states, "illegal state");
    int init = _init[state];
    // prevent from going to zero, to distinguish from never-executed methods
    if (init == 0 && count() > 0)  init = 1;
    int carry = (_counter & carry_mask);    // the carry bit is sticky
    _counter = (init << number_of_noncount_bits) | carry | state;
+   // single write
!   set_raw(counter);
  }
  
+ void InvocationCounter::set_carry_if_necessary() {
+   // single read
+   uint counter = raw_counter();
+ 
+   //update
+   if (!carry(counter) && count(counter) > count_limit / 2) {
+     set_carry_flag(&counter);
+     set_raw(counter);
+   }
+ }
  
  void InvocationCounter::print() {
!   tty->print_cr("invocation count: up = %d, limit = %d, carry = %s, state = %s",
!                                    count(), limit(),
                                     carry() ? "true" : "false",
                                     state_as_string(state()));
!                                    count(), carry() ? "true" : "false");
  }
  
  void InvocationCounter::print_short() {
!   tty->print(" [%d%s;%s]", count(), carry()?"+carry":"", state_as_short_string(state()));
  }
  
  // Initialization
  
  int                       InvocationCounter::_init  [InvocationCounter::number_of_states];
  InvocationCounter::Action InvocationCounter::_action[InvocationCounter::number_of_states];
  int                       InvocationCounter::InterpreterInvocationLimit;
  int                       InvocationCounter::InterpreterBackwardBranchLimit;
  int                       InvocationCounter::InterpreterProfileLimit;
  
  
  const char* InvocationCounter::state_as_string(State state) {
    switch (state) {
      case wait_for_nothing            : return "wait_for_nothing";
      case wait_for_compile            : return "wait_for_compile";
    }
    ShouldNotReachHere();
    return NULL;
  }
  
  const char* InvocationCounter::state_as_short_string(State state) {
    switch (state) {
      case wait_for_nothing            : return "not comp.";
      case wait_for_compile            : return "compileable";
    }
    ShouldNotReachHere();
    return NULL;
  }
  
  
  static address do_nothing(methodHandle method, TRAPS) {
    // dummy action for inactive invocation counters
    MethodCounters* mcs = method->method_counters();
    assert(mcs != NULL, "");
    mcs->invocation_counter()->set_carry();
    mcs->invocation_counter()->set_state(InvocationCounter::wait_for_nothing);
    return NULL;
  }
  
  
  static address do_decay(methodHandle method, TRAPS) {
    // decay invocation counters so compilation gets delayed
    MethodCounters* mcs = method->method_counters();
    assert(mcs != NULL, "");
    mcs->invocation_counter()->decay();
    return NULL;
  }
  
  
  void InvocationCounter::def(State state, int init, Action action) {
    assert(0 <= state && state < number_of_states, "illegal state");
    assert(0 <= init  && init  < count_limit, "initial value out of range");
    _init  [state] = init;
    _action[state] = action;
  }
  
  address dummy_invocation_counter_overflow(methodHandle m, TRAPS) {
    ShouldNotReachHere();
    return NULL;
  }
  
  void InvocationCounter::reinitialize(bool delay_overflow) {
    // define states
    guarantee((int)number_of_states <= (int)state_limit, "adjust number_of_state_bits");
    def(wait_for_nothing, 0, do_nothing);
    if (delay_overflow) {
      def(wait_for_compile, 0, do_decay);
    } else {
      def(wait_for_compile, 0, dummy_invocation_counter_overflow);
    }
  
    InterpreterInvocationLimit = CompileThreshold << number_of_noncount_bits;
    InterpreterProfileLimit = ((CompileThreshold * InterpreterProfilePercentage) / 100)<< number_of_noncount_bits;
  
    // When methodData is collected, the backward branch limit is compared against a
    // methodData counter, rather than an InvocationCounter.  In the former case, we