• file
• revisions
• annotate
• diff
• comparison
• raw

src/share/vm/gc_implementation/g1/g1MMUTracker.cpp@04ff2f6cd0eb (annotated)

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

Tue, 17 Oct 2017 12:58:25 +0800

author

aoqi

date

Tue, 17 Oct 2017 12:58:25 +0800

changeset 7994

04ff2f6cd0eb

parent 6876

710a3c8b516e

child 9931

fd44df5e3bc3

permissions

-rw-r--r--

merge

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2001, 2011, 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	#include "precompiled.hpp"
aoqi@0	26	#include "gc_implementation/g1/g1MMUTracker.hpp"
aoqi@0	27	#include "runtime/mutexLocker.hpp"
aoqi@0	28	#include "utilities/ostream.hpp"
aoqi@0	29
aoqi@0	30	#define _DISABLE_MMU 0
aoqi@0	31
aoqi@0	32	// can't rely on comparing doubles with tolerating a small margin for error
aoqi@0	33	#define SMALL_MARGIN 0.0000001
aoqi@0	34	#define is_double_leq_0(_value) ( (_value) < SMALL_MARGIN )
aoqi@0	35	#define is_double_leq(_val1, _val2) is_double_leq_0((_val1) - (_val2))
aoqi@0	36	#define is_double_geq(_val1, _val2) is_double_leq_0((_val2) - (_val1))
aoqi@0	37
aoqi@0	38	/***** ALL TIMES ARE IN SECS!!!!!!! *****/
aoqi@0	39
aoqi@0	40	G1MMUTracker::G1MMUTracker(double time_slice, double max_gc_time) :
aoqi@0	41	_time_slice(time_slice),
aoqi@0	42	_max_gc_time(max_gc_time) { }
aoqi@0	43
aoqi@0	44	G1MMUTrackerQueue::G1MMUTrackerQueue(double time_slice, double max_gc_time) :
aoqi@0	45	G1MMUTracker(time_slice, max_gc_time),
aoqi@0	46	_head_index(0),
aoqi@0	47	_tail_index(trim_index(_head_index+1)),
aoqi@0	48	_no_entries(0) { }
aoqi@0	49
aoqi@0	50	void G1MMUTrackerQueue::remove_expired_entries(double current_time) {
aoqi@0	51	double limit = current_time - _time_slice;
aoqi@0	52	while (_no_entries > 0) {
aoqi@0	53	if (is_double_geq(limit, _array[_tail_index].end_time())) {
aoqi@0	54	_tail_index = trim_index(_tail_index + 1);
aoqi@0	55	--_no_entries;
aoqi@0	56	} else
aoqi@0	57	return;
aoqi@0	58	}
aoqi@0	59	guarantee(_no_entries == 0, "should have no entries in the array");
aoqi@0	60	}
aoqi@0	61
aoqi@0	62	double G1MMUTrackerQueue::calculate_gc_time(double current_time) {
aoqi@0	63	double gc_time = 0.0;
aoqi@0	64	double limit = current_time - _time_slice;
aoqi@0	65	for (int i = 0; i < _no_entries; ++i) {
aoqi@0	66	int index = trim_index(_tail_index + i);
aoqi@0	67	G1MMUTrackerQueueElem *elem = &_array[index];
aoqi@0	68	if (elem->end_time() > limit) {
aoqi@0	69	if (elem->start_time() > limit)
aoqi@0	70	gc_time += elem->duration();
aoqi@0	71	else
aoqi@0	72	gc_time += elem->end_time() - limit;
aoqi@0	73	}
aoqi@0	74	}
aoqi@0	75	return gc_time;
aoqi@0	76	}
aoqi@0	77
aoqi@0	78	void G1MMUTrackerQueue::add_pause(double start, double end, bool gc_thread) {
aoqi@0	79	double longest_allowed = longest_pause_internal(start);
aoqi@0	80	if (longest_allowed < 0.0)
aoqi@0	81	longest_allowed = 0.0;
aoqi@0	82	double duration = end - start;
aoqi@0	83
aoqi@0	84	remove_expired_entries(end);
aoqi@0	85	if (_no_entries == QueueLength) {
aoqi@0	86	// OK, we've filled up the queue. There are a few ways
aoqi@0	87	// of dealing with this "gracefully"
aoqi@0	88	// increase the array size (:-)
aoqi@0	89	// remove the oldest entry (this might allow more GC time for
aoqi@0	90	// the time slice than what's allowed) - this is what we
aoqi@0	91	// currently do
aoqi@0	92	// consolidate the two entries with the minimum gap between them
aoqi@0	93	// (this might allow less GC time than what's allowed)
aoqi@0	94
aoqi@0	95	// In the case where ScavengeALot is true, such overflow is not
aoqi@0	96	// uncommon; in such cases, we can, without much loss of precision
aoqi@0	97	// or performance (we are GC'ing most of the time anyway!),
aoqi@0	98	// simply overwrite the oldest entry in the tracker.
aoqi@0	99
aoqi@0	100	_head_index = trim_index(_head_index + 1);
aoqi@0	101	assert(_head_index == _tail_index, "Because we have a full circular buffer");
aoqi@0	102	_tail_index = trim_index(_tail_index + 1);
aoqi@0	103	} else {
aoqi@0	104	_head_index = trim_index(_head_index + 1);
aoqi@0	105	++_no_entries;
aoqi@0	106	}
aoqi@0	107	_array[_head_index] = G1MMUTrackerQueueElem(start, end);
aoqi@0	108	}
aoqi@0	109
aoqi@0	110	// basically the _internal call does not remove expired entries
aoqi@0	111	// this is for trying things out in the future and a couple
aoqi@0	112	// of other places (debugging)
aoqi@0	113
aoqi@0	114	double G1MMUTrackerQueue::longest_pause(double current_time) {
aoqi@0	115	if (_DISABLE_MMU)
aoqi@0	116	return _max_gc_time;
aoqi@0	117
aoqi@0	118	MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag);
aoqi@0	119	remove_expired_entries(current_time);
aoqi@0	120
aoqi@0	121	return longest_pause_internal(current_time);
aoqi@0	122	}
aoqi@0	123
aoqi@0	124	double G1MMUTrackerQueue::longest_pause_internal(double current_time) {
aoqi@0	125	double target_time = _max_gc_time;
aoqi@0	126
aoqi@0	127	while( 1 ) {
aoqi@0	128	double gc_time =
aoqi@0	129	calculate_gc_time(current_time + target_time);
aoqi@0	130	double diff = target_time + gc_time - _max_gc_time;
aoqi@0	131	if (!is_double_leq_0(diff)) {
aoqi@0	132	target_time -= diff;
aoqi@0	133	if (is_double_leq_0(target_time)) {
aoqi@0	134	target_time = -1.0;
aoqi@0	135	break;
aoqi@0	136	}
aoqi@0	137	} else {
aoqi@0	138	break;
aoqi@0	139	}
aoqi@0	140	}
aoqi@0	141
aoqi@0	142	return target_time;
aoqi@0	143	}
aoqi@0	144
aoqi@0	145	// basically the _internal call does not remove expired entries
aoqi@0	146	// this is for trying things out in the future and a couple
aoqi@0	147	// of other places (debugging)
aoqi@0	148
aoqi@0	149	double G1MMUTrackerQueue::when_sec(double current_time, double pause_time) {
aoqi@0	150	if (_DISABLE_MMU)
aoqi@0	151	return 0.0;
aoqi@0	152
aoqi@0	153	MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag);
aoqi@0	154	remove_expired_entries(current_time);
aoqi@0	155
aoqi@0	156	return when_internal(current_time, pause_time);
aoqi@0	157	}
aoqi@0	158
aoqi@0	159	double G1MMUTrackerQueue::when_internal(double current_time,
aoqi@0	160	double pause_time) {
aoqi@0	161	// if the pause is over the maximum, just assume that it's the maximum
aoqi@0	162	double adjusted_pause_time =
aoqi@0	163	(pause_time > max_gc_time()) ? max_gc_time() : pause_time;
aoqi@0	164	double earliest_end = current_time + adjusted_pause_time;
aoqi@0	165	double limit = earliest_end - _time_slice;
aoqi@0	166	double gc_time = calculate_gc_time(earliest_end);
aoqi@0	167	double diff = gc_time + adjusted_pause_time - max_gc_time();
aoqi@0	168	if (is_double_leq_0(diff))
aoqi@0	169	return 0.0;
aoqi@0	170
aoqi@0	171	int index = _tail_index;
aoqi@0	172	while ( 1 ) {
aoqi@0	173	G1MMUTrackerQueueElem *elem = &_array[index];
aoqi@0	174	if (elem->end_time() > limit) {
aoqi@0	175	if (elem->start_time() > limit)
aoqi@0	176	diff -= elem->duration();
aoqi@0	177	else
aoqi@0	178	diff -= elem->end_time() - limit;
aoqi@0	179	if (is_double_leq_0(diff))
aoqi@0	180	return elem->end_time() + diff + _time_slice - adjusted_pause_time - current_time;
aoqi@0	181	}
aoqi@0	182	index = trim_index(index+1);
aoqi@0	183	guarantee(index != trim_index(_head_index + 1), "should not go past head");
aoqi@0	184	}
aoqi@0	185	}