Mercurial > hg > truffle
view src/share/vm/interpreter/invocationCounter.hpp @ 20543:e7d0505c8a30
8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso
author | tschatzl |
---|---|
date | Fri, 10 Oct 2014 15:51:58 +0200 |
parents | abe03600372a |
children | d8041d695d19 |
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/* * Copyright (c) 1997, 2012, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP #define SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP #include "memory/allocation.hpp" #include "runtime/handles.hpp" #include "utilities/exceptions.hpp" // 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; friend class ciReplay; 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), 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 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 count_shift = number_of_noncount_bits, count_limit = nth_bit(number_of_count_bits - 1) }; 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 void set_carry_flag() { _counter |= carry_mask; } int raw_counter() { return _counter; } // 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; } #ifdef CC_INTERP // Test counter using scaled limits like the asm interpreter would do rather than doing // the shifts to normalize the counter. // Checks sum of invocation_counter and backedge_counter as the template interpreter does. bool reached_InvocationLimit(InvocationCounter *back_edge_count) const { return (_counter & count_mask) + (back_edge_count->_counter & count_mask) >= (unsigned int) InterpreterInvocationLimit; } bool reached_BackwardBranchLimit(InvocationCounter *back_edge_count) const { return (_counter & count_mask) + (back_edge_count->_counter & count_mask) >= (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 & count_mask) >= (unsigned int) InterpreterProfileLimit; } #endif // CC_INTERP 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); } #endif // SHARE_VM_INTERPRETER_INVOCATIONCOUNTER_HPP