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src/share/vm/gc_implementation/g1/g1MMUTracker.hpp@710a3c8b516e (annotated)

src/share/vm/gc_implementation/g1/g1MMUTracker.hpp

Tue, 08 Aug 2017 15:57:29 +0800

author

aoqi

date

Tue, 08 Aug 2017 15:57:29 +0800

changeset 6876

710a3c8b516e

parent 4153

b9a9ed0f8eeb

parent 0

f90c822e73f8

permissions

-rw-r--r--

merge

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation.
aoqi@0	8	*
aoqi@0	9	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	12	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	13	* accompanied this code).
aoqi@0	14	*
aoqi@0	15	* You should have received a copy of the GNU General Public License version
aoqi@0	16	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	18	*
aoqi@0	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	20	* or visit www.oracle.com if you need additional information or have any
aoqi@0	21	* questions.
aoqi@0	22	*
aoqi@0	23	*/
aoqi@0	24
aoqi@0	25	#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1MMUTRACKER_HPP
aoqi@0	26	#define SHARE_VM_GC_IMPLEMENTATION_G1_G1MMUTRACKER_HPP
aoqi@0	27
aoqi@0	28	#include "memory/allocation.hpp"
aoqi@0	29	#include "utilities/debug.hpp"
aoqi@0	30
aoqi@0	31	// Keeps track of the GC work and decides when it is OK to do GC work
aoqi@0	32	// and for how long so that the MMU invariants are maintained.
aoqi@0	33
aoqi@0	34	/***** ALL TIMES ARE IN SECS!!!!!!! *****/
aoqi@0	35
aoqi@0	36	// this is the "interface"
aoqi@0	37	class G1MMUTracker: public CHeapObj<mtGC> {
aoqi@0	38	protected:
aoqi@0	39	double _time_slice;
aoqi@0	40	double _max_gc_time; // this is per time slice
aoqi@0	41
aoqi@0	42	public:
aoqi@0	43	G1MMUTracker(double time_slice, double max_gc_time);
aoqi@0	44
aoqi@0	45	virtual void add_pause(double start, double end, bool gc_thread) = 0;
aoqi@0	46	virtual double longest_pause(double current_time) = 0;
aoqi@0	47	virtual double when_sec(double current_time, double pause_time) = 0;
aoqi@0	48
aoqi@0	49	double max_gc_time() {
aoqi@0	50	return _max_gc_time;
aoqi@0	51	}
aoqi@0	52
aoqi@0	53	inline bool now_max_gc(double current_time) {
aoqi@0	54	return when_sec(current_time, max_gc_time()) < 0.00001;
aoqi@0	55	}
aoqi@0	56
aoqi@0	57	inline double when_max_gc_sec(double current_time) {
aoqi@0	58	return when_sec(current_time, max_gc_time());
aoqi@0	59	}
aoqi@0	60
aoqi@0	61	inline jlong when_max_gc_ms(double current_time) {
aoqi@0	62	double when = when_max_gc_sec(current_time);
aoqi@0	63	return (jlong) (when * 1000.0);
aoqi@0	64	}
aoqi@0	65
aoqi@0	66	inline jlong when_ms(double current_time, double pause_time) {
aoqi@0	67	double when = when_sec(current_time, pause_time);
aoqi@0	68	return (jlong) (when * 1000.0);
aoqi@0	69	}
aoqi@0	70	};
aoqi@0	71
aoqi@0	72	class G1MMUTrackerQueueElem VALUE_OBJ_CLASS_SPEC {
aoqi@0	73	private:
aoqi@0	74	double _start_time;
aoqi@0	75	double _end_time;
aoqi@0	76
aoqi@0	77	public:
aoqi@0	78	inline double start_time() { return _start_time; }
aoqi@0	79	inline double end_time() { return _end_time; }
aoqi@0	80	inline double duration() { return _end_time - _start_time; }
aoqi@0	81
aoqi@0	82	G1MMUTrackerQueueElem() {
aoqi@0	83	_start_time = 0.0;
aoqi@0	84	_end_time = 0.0;
aoqi@0	85	}
aoqi@0	86
aoqi@0	87	G1MMUTrackerQueueElem(double start_time, double end_time) {
aoqi@0	88	_start_time = start_time;
aoqi@0	89	_end_time = end_time;
aoqi@0	90	}
aoqi@0	91	};
aoqi@0	92
aoqi@0	93	// this is an implementation of the MMUTracker using a (fixed-size) queue
aoqi@0	94	// that keeps track of all the recent pause times
aoqi@0	95	class G1MMUTrackerQueue: public G1MMUTracker {
aoqi@0	96	private:
aoqi@0	97	enum PrivateConstants {
aoqi@0	98	QueueLength = 64
aoqi@0	99	};
aoqi@0	100
aoqi@0	101	// The array keeps track of all the pauses that fall within a time
aoqi@0	102	// slice (the last time slice during which pauses took place).
aoqi@0	103	// The data structure implemented is a circular queue.
aoqi@0	104	// Head "points" to the most recent addition, tail to the oldest one.
aoqi@0	105	// The array is of fixed size and I don't think we'll need more than
aoqi@0	106	// two or three entries with the current behaviour of G1 pauses.
aoqi@0	107	// If the array is full, an easy fix is to look for the pauses with
aoqi@0	108	// the shortest gap between them and consolidate them.
aoqi@0	109	// For now, we have taken the expedient alternative of forgetting
aoqi@0	110	// the oldest entry in the event that +G1UseFixedWindowMMUTracker, thus
aoqi@0	111	// potentially violating MMU specs for some time thereafter.
aoqi@0	112
aoqi@0	113	G1MMUTrackerQueueElem _array[QueueLength];
aoqi@0	114	int _head_index;
aoqi@0	115	int _tail_index;
aoqi@0	116	int _no_entries;
aoqi@0	117
aoqi@0	118	inline int trim_index(int index) {
aoqi@0	119	return (index + QueueLength) % QueueLength;
aoqi@0	120	}
aoqi@0	121
aoqi@0	122	void remove_expired_entries(double current_time);
aoqi@0	123	double calculate_gc_time(double current_time);
aoqi@0	124
aoqi@0	125	double longest_pause_internal(double current_time);
aoqi@0	126	double when_internal(double current_time, double pause_time);
aoqi@0	127
aoqi@0	128	public:
aoqi@0	129	G1MMUTrackerQueue(double time_slice, double max_gc_time);
aoqi@0	130
aoqi@0	131	virtual void add_pause(double start, double end, bool gc_thread);
aoqi@0	132
aoqi@0	133	virtual double longest_pause(double current_time);
aoqi@0	134	virtual double when_sec(double current_time, double pause_time);
aoqi@0	135	};
aoqi@0	136
aoqi@0	137	#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1MMUTRACKER_HPP