Mercurial > hg > graal-compiler
diff src/share/vm/gc_implementation/g1/g1MMUTracker.hpp @ 342:37f87013dfd8
6711316: Open source the Garbage-First garbage collector
Summary: First mercurial integration of the code for the Garbage-First garbage collector.
Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
author | ysr |
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date | Thu, 05 Jun 2008 15:57:56 -0700 |
parents | |
children | fe3d7c11b4b7 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/g1/g1MMUTracker.hpp Thu Jun 05 15:57:56 2008 -0700 @@ -0,0 +1,130 @@ +/* + * Copyright 2001-2007 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. + * + */ + +// Keeps track of the GC work and decides when it is OK to do GC work +// and for how long so that the MMU invariants are maintained. + +/***** ALL TIMES ARE IN SECS!!!!!!! *****/ + +// this is the "interface" +class G1MMUTracker { +protected: + double _time_slice; + double _max_gc_time; // this is per time slice + + double _conc_overhead_time_sec; + +public: + G1MMUTracker(double time_slice, double max_gc_time); + + void update_conc_overhead(double conc_overhead); + + virtual void add_pause(double start, double end, bool gc_thread) = 0; + virtual double longest_pause(double current_time) = 0; + virtual double when_sec(double current_time, double pause_time) = 0; + + double max_gc_time() { + return _max_gc_time - _conc_overhead_time_sec; + } + + inline bool now_max_gc(double current_time) { + return when_sec(current_time, max_gc_time()) < 0.00001; + } + + inline double when_max_gc_sec(double current_time) { + return when_sec(current_time, max_gc_time()); + } + + inline jlong when_max_gc_ms(double current_time) { + double when = when_max_gc_sec(current_time); + return (jlong) (when * 1000.0); + } + + inline jlong when_ms(double current_time, double pause_time) { + double when = when_sec(current_time, pause_time); + return (jlong) (when * 1000.0); + } +}; + +class G1MMUTrackerQueueElem { +private: + double _start_time; + double _end_time; + +public: + inline double start_time() { return _start_time; } + inline double end_time() { return _end_time; } + inline double duration() { return _end_time - _start_time; } + + G1MMUTrackerQueueElem() { + _start_time = 0.0; + _end_time = 0.0; + } + + G1MMUTrackerQueueElem(double start_time, double end_time) { + _start_time = start_time; + _end_time = end_time; + } +}; + +// this is an implementation of the MMUTracker using a (fixed-size) queue +// that keeps track of all the recent pause times +class G1MMUTrackerQueue: public G1MMUTracker { +private: + enum PrivateConstants { + QueueLength = 64 + }; + + // The array keeps track of all the pauses that fall within a time + // slice (the last time slice during which pauses took place). + // The data structure implemented is a circular queue. + // Head "points" to the most recent addition, tail to the oldest one. + // The array is of fixed size and I don't think we'll need more than + // two or three entries with the current behaviour of G1 pauses. + // If the array is full, an easy fix is to look for the pauses with + // the shortest gap between them and concolidate them. + + G1MMUTrackerQueueElem _array[QueueLength]; + int _head_index; + int _tail_index; + int _no_entries; + + inline int trim_index(int index) { + return (index + QueueLength) % QueueLength; + } + + void remove_expired_entries(double current_time); + double calculate_gc_time(double current_time); + + double longest_pause_internal(double current_time); + double when_internal(double current_time, double pause_time); + +public: + G1MMUTrackerQueue(double time_slice, double max_gc_time); + + virtual void add_pause(double start, double end, bool gc_thread); + + virtual double longest_pause(double current_time); + virtual double when_sec(double current_time, double pause_time); +};