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src/share/vm/gc_implementation/shared/adaptiveSizePolicy.cpp@89e0543e1737 (annotated)

src/share/vm/gc_implementation/shared/adaptiveSizePolicy.cpp

Tue, 22 Sep 2009 14:06:10 -0700

author

xdono

date

Tue, 22 Sep 2009 14:06:10 -0700

changeset 1383

89e0543e1737

parent 435

a61af66fc99e

child 1822

0bfd3fb24150

permissions

-rw-r--r--

6884624: Update copyright year
Summary: Update copyright for files that have been modified in 2009 through Septermber
Reviewed-by: tbell, ohair

duke@435	1	/*
duke@435	2	* Copyright 2004-2006 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24	#include "incls/_precompiled.incl"
duke@435	25	#include "incls/_adaptiveSizePolicy.cpp.incl"
duke@435	26
duke@435	27	elapsedTimer AdaptiveSizePolicy::_minor_timer;
duke@435	28	elapsedTimer AdaptiveSizePolicy::_major_timer;
duke@435	29
duke@435	30	// The throughput goal is implemented as
duke@435	31	// _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio))
duke@435	32	// gc_cost_ratio is the ratio
duke@435	33	// application cost / gc cost
duke@435	34	// For example a gc_cost_ratio of 4 translates into a
duke@435	35	// throughput goal of .80
duke@435	36
duke@435	37	AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size,
duke@435	38	size_t init_promo_size,
duke@435	39	size_t init_survivor_size,
duke@435	40	double gc_pause_goal_sec,
duke@435	41	uint gc_cost_ratio) :
duke@435	42	_eden_size(init_eden_size),
duke@435	43	_promo_size(init_promo_size),
duke@435	44	_survivor_size(init_survivor_size),
duke@435	45	_gc_pause_goal_sec(gc_pause_goal_sec),
duke@435	46	_throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))),
duke@435	47	_gc_time_limit_exceeded(false),
duke@435	48	_print_gc_time_limit_would_be_exceeded(false),
duke@435	49	_gc_time_limit_count(0),
duke@435	50	_latest_minor_mutator_interval_seconds(0),
duke@435	51	_threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0),
duke@435	52	_young_gen_change_for_minor_throughput(0),
duke@435	53	_old_gen_change_for_major_throughput(0) {
duke@435	54	_avg_minor_pause =
duke@435	55	new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
duke@435	56	_avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435	57	_avg_minor_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435	58	_avg_major_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435	59
duke@435	60	_avg_young_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
duke@435	61	_avg_old_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
duke@435	62	_avg_eden_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
duke@435	63
duke@435	64	_avg_survived = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight,
duke@435	65	SurvivorPadding);
duke@435	66	_avg_pretenured = new AdaptivePaddedNoZeroDevAverage(
duke@435	67	AdaptiveSizePolicyWeight,
duke@435	68	SurvivorPadding);
duke@435	69
duke@435	70	_minor_pause_old_estimator =
duke@435	71	new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435	72	_minor_pause_young_estimator =
duke@435	73	new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435	74	_minor_collection_estimator =
duke@435	75	new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435	76	_major_collection_estimator =
duke@435	77	new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435	78
duke@435	79	// Start the timers
duke@435	80	_minor_timer.start();
duke@435	81
duke@435	82	_young_gen_policy_is_ready = false;
duke@435	83	}
duke@435	84
duke@435	85	bool AdaptiveSizePolicy::tenuring_threshold_change() const {
duke@435	86	return decrement_tenuring_threshold_for_gc_cost() ||
duke@435	87	increment_tenuring_threshold_for_gc_cost() ||
duke@435	88	decrement_tenuring_threshold_for_survivor_limit();
duke@435	89	}
duke@435	90
duke@435	91	void AdaptiveSizePolicy::minor_collection_begin() {
duke@435	92	// Update the interval time
duke@435	93	_minor_timer.stop();
duke@435	94	// Save most recent collection time
duke@435	95	_latest_minor_mutator_interval_seconds = _minor_timer.seconds();
duke@435	96	_minor_timer.reset();
duke@435	97	_minor_timer.start();
duke@435	98	}
duke@435	99
duke@435	100	void AdaptiveSizePolicy::update_minor_pause_young_estimator(
duke@435	101	double minor_pause_in_ms) {
duke@435	102	double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
duke@435	103	_minor_pause_young_estimator->update(eden_size_in_mbytes,
duke@435	104	minor_pause_in_ms);
duke@435	105	}
duke@435	106
duke@435	107	void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) {
duke@435	108	// Update the pause time.
duke@435	109	_minor_timer.stop();
duke@435	110
duke@435	111	if (gc_cause != GCCause::_java_lang_system_gc ||
duke@435	112	UseAdaptiveSizePolicyWithSystemGC) {
duke@435	113	double minor_pause_in_seconds = _minor_timer.seconds();
duke@435	114	double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS;
duke@435	115
duke@435	116	// Sample for performance counter
duke@435	117	_avg_minor_pause->sample(minor_pause_in_seconds);
duke@435	118
duke@435	119	// Cost of collection (unit-less)
duke@435	120	double collection_cost = 0.0;
duke@435	121	if ((_latest_minor_mutator_interval_seconds > 0.0) &&
duke@435	122	(minor_pause_in_seconds > 0.0)) {
duke@435	123	double interval_in_seconds =
duke@435	124	_latest_minor_mutator_interval_seconds + minor_pause_in_seconds;
duke@435	125	collection_cost =
duke@435	126	minor_pause_in_seconds / interval_in_seconds;
duke@435	127	_avg_minor_gc_cost->sample(collection_cost);
duke@435	128	// Sample for performance counter
duke@435	129	_avg_minor_interval->sample(interval_in_seconds);
duke@435	130	}
duke@435	131
duke@435	132	// The policy does not have enough data until at least some
duke@435	133	// minor collections have been done.
duke@435	134	_young_gen_policy_is_ready =
duke@435	135	(_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold);
duke@435	136
duke@435	137	// Calculate variables used to estimate pause time vs. gen sizes
duke@435	138	double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
duke@435	139	update_minor_pause_young_estimator(minor_pause_in_ms);
duke@435	140	update_minor_pause_old_estimator(minor_pause_in_ms);
duke@435	141
duke@435	142	if (PrintAdaptiveSizePolicy && Verbose) {
duke@435	143	gclog_or_tty->print("AdaptiveSizePolicy::minor_collection_end: "
duke@435	144	"minor gc cost: %f average: %f", collection_cost,
duke@435	145	_avg_minor_gc_cost->average());
duke@435	146	gclog_or_tty->print_cr(" minor pause: %f minor period %f",
duke@435	147	minor_pause_in_ms,
duke@435	148	_latest_minor_mutator_interval_seconds * MILLIUNITS);
duke@435	149	}
duke@435	150
duke@435	151	// Calculate variable used to estimate collection cost vs. gen sizes
duke@435	152	assert(collection_cost >= 0.0, "Expected to be non-negative");
duke@435	153	_minor_collection_estimator->update(eden_size_in_mbytes, collection_cost);
duke@435	154	}
duke@435	155
duke@435	156	// Interval times use this timer to measure the mutator time.
duke@435	157	// Reset the timer after the GC pause.
duke@435	158	_minor_timer.reset();
duke@435	159	_minor_timer.start();
duke@435	160	}
duke@435	161
duke@435	162	size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden,
duke@435	163	uint percent_change) {
duke@435	164	size_t eden_heap_delta;
duke@435	165	eden_heap_delta = cur_eden / 100 * percent_change;
duke@435	166	return eden_heap_delta;
duke@435	167	}
duke@435	168
duke@435	169	size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) {
duke@435	170	return eden_increment(cur_eden, YoungGenerationSizeIncrement);
duke@435	171	}
duke@435	172
duke@435	173	size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
duke@435	174	size_t eden_heap_delta = eden_increment(cur_eden) /
duke@435	175	AdaptiveSizeDecrementScaleFactor;
duke@435	176	return eden_heap_delta;
duke@435	177	}
duke@435	178
duke@435	179	size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo,
duke@435	180	uint percent_change) {
duke@435	181	size_t promo_heap_delta;
duke@435	182	promo_heap_delta = cur_promo / 100 * percent_change;
duke@435	183	return promo_heap_delta;
duke@435	184	}
duke@435	185
duke@435	186	size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) {
duke@435	187	return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
duke@435	188	}
duke@435	189
duke@435	190	size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
duke@435	191	size_t promo_heap_delta = promo_increment(cur_promo);
duke@435	192	promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
duke@435	193	return promo_heap_delta;
duke@435	194	}
duke@435	195
duke@435	196	double AdaptiveSizePolicy::time_since_major_gc() const {
duke@435	197	_major_timer.stop();
duke@435	198	double result = _major_timer.seconds();
duke@435	199	_major_timer.start();
duke@435	200	return result;
duke@435	201	}
duke@435	202
duke@435	203	// Linear decay of major gc cost
duke@435	204	double AdaptiveSizePolicy::decaying_major_gc_cost() const {
duke@435	205	double major_interval = major_gc_interval_average_for_decay();
duke@435	206	double major_gc_cost_average = major_gc_cost();
duke@435	207	double decayed_major_gc_cost = major_gc_cost_average;
duke@435	208	if(time_since_major_gc() > 0.0) {
duke@435	209	decayed_major_gc_cost = major_gc_cost() *
duke@435	210	(((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval)
duke@435	211	/ time_since_major_gc();
duke@435	212	}
duke@435	213
duke@435	214	// The decayed cost should always be smaller than the
duke@435	215	// average cost but the vagaries of finite arithmetic could
duke@435	216	// produce a larger value in decayed_major_gc_cost so protect
duke@435	217	// against that.
duke@435	218	return MIN2(major_gc_cost_average, decayed_major_gc_cost);
duke@435	219	}
duke@435	220
duke@435	221	// Use a value of the major gc cost that has been decayed
duke@435	222	// by the factor
duke@435	223	//
duke@435	224	// average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale /
duke@435	225	// time-since-last-major-gc
duke@435	226	//
duke@435	227	// if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale
duke@435	228	// is less than time-since-last-major-gc.
duke@435	229	//
duke@435	230	// In cases where there are initial major gc's that
duke@435	231	// are of a relatively high cost but no later major
duke@435	232	// gc's, the total gc cost can remain high because
duke@435	233	// the major gc cost remains unchanged (since there are no major
duke@435	234	// gc's). In such a situation the value of the unchanging
duke@435	235	// major gc cost can keep the mutator throughput below
duke@435	236	// the goal when in fact the major gc cost is becoming diminishingly
duke@435	237	// small. Use the decaying gc cost only to decide whether to
duke@435	238	// adjust for throughput. Using it also to determine the adjustment
duke@435	239	// to be made for throughput also seems reasonable but there is
duke@435	240	// no test case to use to decide if it is the right thing to do
duke@435	241	// don't do it yet.
duke@435	242
duke@435	243	double AdaptiveSizePolicy::decaying_gc_cost() const {
duke@435	244	double decayed_major_gc_cost = major_gc_cost();
duke@435	245	double avg_major_interval = major_gc_interval_average_for_decay();
duke@435	246	if (UseAdaptiveSizeDecayMajorGCCost &&
duke@435	247	(AdaptiveSizeMajorGCDecayTimeScale > 0) &&
duke@435	248	(avg_major_interval > 0.00)) {
duke@435	249	double time_since_last_major_gc = time_since_major_gc();
duke@435	250
duke@435	251	// Decay the major gc cost?
duke@435	252	if (time_since_last_major_gc >
duke@435	253	((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) {
duke@435	254
duke@435	255	// Decay using the time-since-last-major-gc
duke@435	256	decayed_major_gc_cost = decaying_major_gc_cost();
duke@435	257	if (PrintGCDetails && Verbose) {
duke@435	258	gclog_or_tty->print_cr("\ndecaying_gc_cost: major interval average:"
duke@435	259	" %f time since last major gc: %f",
duke@435	260	avg_major_interval, time_since_last_major_gc);
duke@435	261	gclog_or_tty->print_cr(" major gc cost: %f decayed major gc cost: %f",
duke@435	262	major_gc_cost(), decayed_major_gc_cost);
duke@435	263	}
duke@435	264	}
duke@435	265	}
duke@435	266	double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost());
duke@435	267	return result;
duke@435	268	}
duke@435	269
duke@435	270
duke@435	271	void AdaptiveSizePolicy::clear_generation_free_space_flags() {
duke@435	272	set_change_young_gen_for_min_pauses(0);
duke@435	273	set_change_old_gen_for_maj_pauses(0);
duke@435	274
duke@435	275	set_change_old_gen_for_throughput(0);
duke@435	276	set_change_young_gen_for_throughput(0);
duke@435	277	set_decrease_for_footprint(0);
duke@435	278	set_decide_at_full_gc(0);
duke@435	279	}
duke@435	280
duke@435	281	// Printing
duke@435	282
duke@435	283	bool AdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) const {
duke@435	284
duke@435	285	// Should only be used with adaptive size policy turned on.
duke@435	286	// Otherwise, there may be variables that are undefined.
duke@435	287	if (!UseAdaptiveSizePolicy) return false;
duke@435	288
duke@435	289	// Print goal for which action is needed.
duke@435	290	char* action = NULL;
duke@435	291	bool change_for_pause = false;
duke@435	292	if ((change_old_gen_for_maj_pauses() ==
duke@435	293	decrease_old_gen_for_maj_pauses_true) ||
duke@435	294	(change_young_gen_for_min_pauses() ==
duke@435	295	decrease_young_gen_for_min_pauses_true)) {
duke@435	296	action = (char*) " *** pause time goal ***";
duke@435	297	change_for_pause = true;
duke@435	298	} else if ((change_old_gen_for_throughput() ==
duke@435	299	increase_old_gen_for_throughput_true) ||
duke@435	300	(change_young_gen_for_throughput() ==
duke@435	301	increase_young_gen_for_througput_true)) {
duke@435	302	action = (char*) " *** throughput goal ***";
duke@435	303	} else if (decrease_for_footprint()) {
duke@435	304	action = (char*) " *** reduced footprint ***";
duke@435	305	} else {
duke@435	306	// No actions were taken. This can legitimately be the
duke@435	307	// situation if not enough data has been gathered to make
duke@435	308	// decisions.
duke@435	309	return false;
duke@435	310	}
duke@435	311
duke@435	312	// Pauses
duke@435	313	// Currently the size of the old gen is only adjusted to
duke@435	314	// change the major pause times.
duke@435	315	char* young_gen_action = NULL;
duke@435	316	char* tenured_gen_action = NULL;
duke@435	317
duke@435	318	char* shrink_msg = (char*) "(attempted to shrink)";
duke@435	319	char* grow_msg = (char*) "(attempted to grow)";
duke@435	320	char* no_change_msg = (char*) "(no change)";
duke@435	321	if (change_young_gen_for_min_pauses() ==
duke@435	322	decrease_young_gen_for_min_pauses_true) {
duke@435	323	young_gen_action = shrink_msg;
duke@435	324	} else if (change_for_pause) {
duke@435	325	young_gen_action = no_change_msg;
duke@435	326	}
duke@435	327
duke@435	328	if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) {
duke@435	329	tenured_gen_action = shrink_msg;
duke@435	330	} else if (change_for_pause) {
duke@435	331	tenured_gen_action = no_change_msg;
duke@435	332	}
duke@435	333
duke@435	334	// Throughput
duke@435	335	if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) {
duke@435	336	assert(change_young_gen_for_throughput() ==
duke@435	337	increase_young_gen_for_througput_true,
duke@435	338	"Both generations should be growing");
duke@435	339	young_gen_action = grow_msg;
duke@435	340	tenured_gen_action = grow_msg;
duke@435	341	} else if (change_young_gen_for_throughput() ==
duke@435	342	increase_young_gen_for_througput_true) {
duke@435	343	// Only the young generation may grow at start up (before
duke@435	344	// enough full collections have been done to grow the old generation).
duke@435	345	young_gen_action = grow_msg;
duke@435	346	tenured_gen_action = no_change_msg;
duke@435	347	}
duke@435	348
duke@435	349	// Minimum footprint
duke@435	350	if (decrease_for_footprint() != 0) {
duke@435	351	young_gen_action = shrink_msg;
duke@435	352	tenured_gen_action = shrink_msg;
duke@435	353	}
duke@435	354
duke@435	355	st->print_cr(" UseAdaptiveSizePolicy actions to meet %s", action);
duke@435	356	st->print_cr(" GC overhead (%%)");
duke@435	357	st->print_cr(" Young generation: %7.2f\t %s",
duke@435	358	100.0 * avg_minor_gc_cost()->average(),
duke@435	359	young_gen_action);
duke@435	360	st->print_cr(" Tenured generation: %7.2f\t %s",
duke@435	361	100.0 * avg_major_gc_cost()->average(),
duke@435	362	tenured_gen_action);
duke@435	363	return true;
duke@435	364	}
duke@435	365
duke@435	366	bool AdaptiveSizePolicy::print_adaptive_size_policy_on(
duke@435	367	outputStream* st,
duke@435	368	int tenuring_threshold_arg) const {
duke@435	369	if (!AdaptiveSizePolicy::print_adaptive_size_policy_on(st)) {
duke@435	370	return false;
duke@435	371	}
duke@435	372
duke@435	373	// Tenuring threshold
duke@435	374	bool tenuring_threshold_changed = true;
duke@435	375	if (decrement_tenuring_threshold_for_survivor_limit()) {
duke@435	376	st->print(" Tenuring threshold: (attempted to decrease to avoid"
duke@435	377	" survivor space overflow) = ");
duke@435	378	} else if (decrement_tenuring_threshold_for_gc_cost()) {
duke@435	379	st->print(" Tenuring threshold: (attempted to decrease to balance"
duke@435	380	" GC costs) = ");
duke@435	381	} else if (increment_tenuring_threshold_for_gc_cost()) {
duke@435	382	st->print(" Tenuring threshold: (attempted to increase to balance"
duke@435	383	" GC costs) = ");
duke@435	384	} else {
duke@435	385	tenuring_threshold_changed = false;
duke@435	386	assert(!tenuring_threshold_change(), "(no change was attempted)");
duke@435	387	}
duke@435	388	if (tenuring_threshold_changed) {
duke@435	389	st->print_cr("%d", tenuring_threshold_arg);
duke@435	390	}
duke@435	391	return true;
duke@435	392	}