Mercurial > hg > truffle
diff src/share/vm/interpreter/invocationCounter.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | c18cbe5936b8 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/interpreter/invocationCounter.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,137 @@ +/* + * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +// InvocationCounters are used to trigger actions when a limit (threshold) is reached. +// For different states, different limits and actions can be defined in the initialization +// routine of InvocationCounters. +// +// Implementation notes: For space reasons, state & counter are both encoded in one word, +// The state is encoded using some of the least significant bits, the counter is using the +// more significant bits. The counter is incremented before a method is activated and an +// action is triggered when when count() > limit(). + +class InvocationCounter VALUE_OBJ_CLASS_SPEC { + friend class VMStructs; + private: // bit no: |31 3| 2 | 1 0 | + unsigned int _counter; // format: [count|carry|state] + + enum PrivateConstants { + number_of_state_bits = 2, + number_of_carry_bits = 1, + number_of_noncount_bits = number_of_state_bits + number_of_carry_bits, + number_of_count_bits = BitsPerInt - number_of_noncount_bits, + state_limit = nth_bit(number_of_state_bits), + count_grain = nth_bit(number_of_state_bits + number_of_carry_bits), + count_limit = nth_bit(number_of_count_bits - 1), + carry_mask = right_n_bits(number_of_carry_bits) << number_of_state_bits, + state_mask = right_n_bits(number_of_state_bits), + status_mask = right_n_bits(number_of_state_bits + number_of_carry_bits), + count_mask = ((int)(-1) ^ status_mask) + }; + + public: + static int InterpreterInvocationLimit; // CompileThreshold scaled for interpreter use + static int Tier1InvocationLimit; // CompileThreshold scaled for tier1 use + static int Tier1BackEdgeLimit; // BackEdgeThreshold scaled for tier1 use + + static int InterpreterBackwardBranchLimit; // A separate threshold for on stack replacement + + static int InterpreterProfileLimit; // Profiling threshold scaled for interpreter use + + typedef address (*Action)(methodHandle method, TRAPS); + + enum PublicConstants { + count_increment = count_grain, // use this value to increment the 32bit _counter word + count_mask_value = count_mask // use this value to mask the backedge counter + }; + + enum State { + wait_for_nothing, // do nothing when count() > limit() + wait_for_compile, // introduce nmethod when count() > limit() + number_of_states // must be <= state_limit + }; + + // Manipulation + void reset(); // sets state to wait state + void init(); // sets state into original state + void set_state(State state); // sets state and initializes counter correspondingly + inline void set(State state, int count); // sets state and counter + inline void decay(); // decay counter (divide by two) + void set_carry(); // set the sticky carry bit + + // Accessors + State state() const { return (State)(_counter & state_mask); } + bool carry() const { return (_counter & carry_mask) != 0; } + int limit() const { return CompileThreshold; } + Action action() const { return _action[state()]; } + int count() const { return _counter >> number_of_noncount_bits; } + + int get_InvocationLimit() const { return InterpreterInvocationLimit >> number_of_noncount_bits; } + int get_BackwardBranchLimit() const { return InterpreterBackwardBranchLimit >> number_of_noncount_bits; } + int get_ProfileLimit() const { return InterpreterProfileLimit >> number_of_noncount_bits; } + + // Test counter using scaled limits like the asm interpreter would do rather than doing + // the shifts to normalize the counter. + + bool reached_InvocationLimit() const { return _counter >= (unsigned int) InterpreterInvocationLimit; } + bool reached_BackwardBranchLimit() const { return _counter >= (unsigned int) InterpreterBackwardBranchLimit; } + + // Do this just like asm interpreter does for max speed + bool reached_ProfileLimit(InvocationCounter *back_edge_count) const { + return (_counter && count_mask) + back_edge_count->_counter >= (unsigned int) InterpreterProfileLimit; + } + + void increment() { _counter += count_increment; } + + + // Printing + void print(); + void print_short(); + + // Miscellaneous + static ByteSize counter_offset() { return byte_offset_of(InvocationCounter, _counter); } + static void reinitialize(bool delay_overflow); + + private: + static int _init [number_of_states]; // the counter limits + static Action _action[number_of_states]; // the actions + + static void def(State state, int init, Action action); + static const char* state_as_string(State state); + static const char* state_as_short_string(State state); +}; + +inline void InvocationCounter::set(State state, int count) { + assert(0 <= state && state < number_of_states, "illegal state"); + int carry = (_counter & carry_mask); // the carry bit is sticky + _counter = (count << number_of_noncount_bits) | carry | state; +} + +inline void InvocationCounter::decay() { + int c = count(); + int new_count = c >> 1; + // prevent from going to zero, to distinguish from never-executed methods + if (c > 0 && new_count == 0) new_count = 1; + set(state(), new_count); +}