1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/shared/adaptiveSizePolicy.cpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,392 @@
1.4 +/*
1.5 + * Copyright 2004-2006 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +#include "incls/_precompiled.incl"
1.28 +#include "incls/_adaptiveSizePolicy.cpp.incl"
1.29 +
1.30 +elapsedTimer AdaptiveSizePolicy::_minor_timer;
1.31 +elapsedTimer AdaptiveSizePolicy::_major_timer;
1.32 +
1.33 +// The throughput goal is implemented as
1.34 +// _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio))
1.35 +// gc_cost_ratio is the ratio
1.36 +// application cost / gc cost
1.37 +// For example a gc_cost_ratio of 4 translates into a
1.38 +// throughput goal of .80
1.39 +
1.40 +AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size,
1.41 + size_t init_promo_size,
1.42 + size_t init_survivor_size,
1.43 + double gc_pause_goal_sec,
1.44 + uint gc_cost_ratio) :
1.45 + _eden_size(init_eden_size),
1.46 + _promo_size(init_promo_size),
1.47 + _survivor_size(init_survivor_size),
1.48 + _gc_pause_goal_sec(gc_pause_goal_sec),
1.49 + _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))),
1.50 + _gc_time_limit_exceeded(false),
1.51 + _print_gc_time_limit_would_be_exceeded(false),
1.52 + _gc_time_limit_count(0),
1.53 + _latest_minor_mutator_interval_seconds(0),
1.54 + _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0),
1.55 + _young_gen_change_for_minor_throughput(0),
1.56 + _old_gen_change_for_major_throughput(0) {
1.57 + _avg_minor_pause =
1.58 + new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
1.59 + _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
1.60 + _avg_minor_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
1.61 + _avg_major_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
1.62 +
1.63 + _avg_young_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
1.64 + _avg_old_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
1.65 + _avg_eden_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
1.66 +
1.67 + _avg_survived = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight,
1.68 + SurvivorPadding);
1.69 + _avg_pretenured = new AdaptivePaddedNoZeroDevAverage(
1.70 + AdaptiveSizePolicyWeight,
1.71 + SurvivorPadding);
1.72 +
1.73 + _minor_pause_old_estimator =
1.74 + new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
1.75 + _minor_pause_young_estimator =
1.76 + new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
1.77 + _minor_collection_estimator =
1.78 + new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
1.79 + _major_collection_estimator =
1.80 + new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
1.81 +
1.82 + // Start the timers
1.83 + _minor_timer.start();
1.84 +
1.85 + _young_gen_policy_is_ready = false;
1.86 +}
1.87 +
1.88 +bool AdaptiveSizePolicy::tenuring_threshold_change() const {
1.89 + return decrement_tenuring_threshold_for_gc_cost() ||
1.90 + increment_tenuring_threshold_for_gc_cost() ||
1.91 + decrement_tenuring_threshold_for_survivor_limit();
1.92 +}
1.93 +
1.94 +void AdaptiveSizePolicy::minor_collection_begin() {
1.95 + // Update the interval time
1.96 + _minor_timer.stop();
1.97 + // Save most recent collection time
1.98 + _latest_minor_mutator_interval_seconds = _minor_timer.seconds();
1.99 + _minor_timer.reset();
1.100 + _minor_timer.start();
1.101 +}
1.102 +
1.103 +void AdaptiveSizePolicy::update_minor_pause_young_estimator(
1.104 + double minor_pause_in_ms) {
1.105 + double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
1.106 + _minor_pause_young_estimator->update(eden_size_in_mbytes,
1.107 + minor_pause_in_ms);
1.108 +}
1.109 +
1.110 +void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) {
1.111 + // Update the pause time.
1.112 + _minor_timer.stop();
1.113 +
1.114 + if (gc_cause != GCCause::_java_lang_system_gc ||
1.115 + UseAdaptiveSizePolicyWithSystemGC) {
1.116 + double minor_pause_in_seconds = _minor_timer.seconds();
1.117 + double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS;
1.118 +
1.119 + // Sample for performance counter
1.120 + _avg_minor_pause->sample(minor_pause_in_seconds);
1.121 +
1.122 + // Cost of collection (unit-less)
1.123 + double collection_cost = 0.0;
1.124 + if ((_latest_minor_mutator_interval_seconds > 0.0) &&
1.125 + (minor_pause_in_seconds > 0.0)) {
1.126 + double interval_in_seconds =
1.127 + _latest_minor_mutator_interval_seconds + minor_pause_in_seconds;
1.128 + collection_cost =
1.129 + minor_pause_in_seconds / interval_in_seconds;
1.130 + _avg_minor_gc_cost->sample(collection_cost);
1.131 + // Sample for performance counter
1.132 + _avg_minor_interval->sample(interval_in_seconds);
1.133 + }
1.134 +
1.135 + // The policy does not have enough data until at least some
1.136 + // minor collections have been done.
1.137 + _young_gen_policy_is_ready =
1.138 + (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold);
1.139 +
1.140 + // Calculate variables used to estimate pause time vs. gen sizes
1.141 + double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
1.142 + update_minor_pause_young_estimator(minor_pause_in_ms);
1.143 + update_minor_pause_old_estimator(minor_pause_in_ms);
1.144 +
1.145 + if (PrintAdaptiveSizePolicy && Verbose) {
1.146 + gclog_or_tty->print("AdaptiveSizePolicy::minor_collection_end: "
1.147 + "minor gc cost: %f average: %f", collection_cost,
1.148 + _avg_minor_gc_cost->average());
1.149 + gclog_or_tty->print_cr(" minor pause: %f minor period %f",
1.150 + minor_pause_in_ms,
1.151 + _latest_minor_mutator_interval_seconds * MILLIUNITS);
1.152 + }
1.153 +
1.154 + // Calculate variable used to estimate collection cost vs. gen sizes
1.155 + assert(collection_cost >= 0.0, "Expected to be non-negative");
1.156 + _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost);
1.157 + }
1.158 +
1.159 + // Interval times use this timer to measure the mutator time.
1.160 + // Reset the timer after the GC pause.
1.161 + _minor_timer.reset();
1.162 + _minor_timer.start();
1.163 +}
1.164 +
1.165 +size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden,
1.166 + uint percent_change) {
1.167 + size_t eden_heap_delta;
1.168 + eden_heap_delta = cur_eden / 100 * percent_change;
1.169 + return eden_heap_delta;
1.170 +}
1.171 +
1.172 +size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) {
1.173 + return eden_increment(cur_eden, YoungGenerationSizeIncrement);
1.174 +}
1.175 +
1.176 +size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
1.177 + size_t eden_heap_delta = eden_increment(cur_eden) /
1.178 + AdaptiveSizeDecrementScaleFactor;
1.179 + return eden_heap_delta;
1.180 +}
1.181 +
1.182 +size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo,
1.183 + uint percent_change) {
1.184 + size_t promo_heap_delta;
1.185 + promo_heap_delta = cur_promo / 100 * percent_change;
1.186 + return promo_heap_delta;
1.187 +}
1.188 +
1.189 +size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) {
1.190 + return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
1.191 +}
1.192 +
1.193 +size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
1.194 + size_t promo_heap_delta = promo_increment(cur_promo);
1.195 + promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
1.196 + return promo_heap_delta;
1.197 +}
1.198 +
1.199 +double AdaptiveSizePolicy::time_since_major_gc() const {
1.200 + _major_timer.stop();
1.201 + double result = _major_timer.seconds();
1.202 + _major_timer.start();
1.203 + return result;
1.204 +}
1.205 +
1.206 +// Linear decay of major gc cost
1.207 +double AdaptiveSizePolicy::decaying_major_gc_cost() const {
1.208 + double major_interval = major_gc_interval_average_for_decay();
1.209 + double major_gc_cost_average = major_gc_cost();
1.210 + double decayed_major_gc_cost = major_gc_cost_average;
1.211 + if(time_since_major_gc() > 0.0) {
1.212 + decayed_major_gc_cost = major_gc_cost() *
1.213 + (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval)
1.214 + / time_since_major_gc();
1.215 + }
1.216 +
1.217 + // The decayed cost should always be smaller than the
1.218 + // average cost but the vagaries of finite arithmetic could
1.219 + // produce a larger value in decayed_major_gc_cost so protect
1.220 + // against that.
1.221 + return MIN2(major_gc_cost_average, decayed_major_gc_cost);
1.222 +}
1.223 +
1.224 +// Use a value of the major gc cost that has been decayed
1.225 +// by the factor
1.226 +//
1.227 +// average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale /
1.228 +// time-since-last-major-gc
1.229 +//
1.230 +// if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale
1.231 +// is less than time-since-last-major-gc.
1.232 +//
1.233 +// In cases where there are initial major gc's that
1.234 +// are of a relatively high cost but no later major
1.235 +// gc's, the total gc cost can remain high because
1.236 +// the major gc cost remains unchanged (since there are no major
1.237 +// gc's). In such a situation the value of the unchanging
1.238 +// major gc cost can keep the mutator throughput below
1.239 +// the goal when in fact the major gc cost is becoming diminishingly
1.240 +// small. Use the decaying gc cost only to decide whether to
1.241 +// adjust for throughput. Using it also to determine the adjustment
1.242 +// to be made for throughput also seems reasonable but there is
1.243 +// no test case to use to decide if it is the right thing to do
1.244 +// don't do it yet.
1.245 +
1.246 +double AdaptiveSizePolicy::decaying_gc_cost() const {
1.247 + double decayed_major_gc_cost = major_gc_cost();
1.248 + double avg_major_interval = major_gc_interval_average_for_decay();
1.249 + if (UseAdaptiveSizeDecayMajorGCCost &&
1.250 + (AdaptiveSizeMajorGCDecayTimeScale > 0) &&
1.251 + (avg_major_interval > 0.00)) {
1.252 + double time_since_last_major_gc = time_since_major_gc();
1.253 +
1.254 + // Decay the major gc cost?
1.255 + if (time_since_last_major_gc >
1.256 + ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) {
1.257 +
1.258 + // Decay using the time-since-last-major-gc
1.259 + decayed_major_gc_cost = decaying_major_gc_cost();
1.260 + if (PrintGCDetails && Verbose) {
1.261 + gclog_or_tty->print_cr("\ndecaying_gc_cost: major interval average:"
1.262 + " %f time since last major gc: %f",
1.263 + avg_major_interval, time_since_last_major_gc);
1.264 + gclog_or_tty->print_cr(" major gc cost: %f decayed major gc cost: %f",
1.265 + major_gc_cost(), decayed_major_gc_cost);
1.266 + }
1.267 + }
1.268 + }
1.269 + double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost());
1.270 + return result;
1.271 +}
1.272 +
1.273 +
1.274 +void AdaptiveSizePolicy::clear_generation_free_space_flags() {
1.275 + set_change_young_gen_for_min_pauses(0);
1.276 + set_change_old_gen_for_maj_pauses(0);
1.277 +
1.278 + set_change_old_gen_for_throughput(0);
1.279 + set_change_young_gen_for_throughput(0);
1.280 + set_decrease_for_footprint(0);
1.281 + set_decide_at_full_gc(0);
1.282 +}
1.283 +
1.284 +// Printing
1.285 +
1.286 +bool AdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) const {
1.287 +
1.288 + // Should only be used with adaptive size policy turned on.
1.289 + // Otherwise, there may be variables that are undefined.
1.290 + if (!UseAdaptiveSizePolicy) return false;
1.291 +
1.292 + // Print goal for which action is needed.
1.293 + char* action = NULL;
1.294 + bool change_for_pause = false;
1.295 + if ((change_old_gen_for_maj_pauses() ==
1.296 + decrease_old_gen_for_maj_pauses_true) ||
1.297 + (change_young_gen_for_min_pauses() ==
1.298 + decrease_young_gen_for_min_pauses_true)) {
1.299 + action = (char*) " *** pause time goal ***";
1.300 + change_for_pause = true;
1.301 + } else if ((change_old_gen_for_throughput() ==
1.302 + increase_old_gen_for_throughput_true) ||
1.303 + (change_young_gen_for_throughput() ==
1.304 + increase_young_gen_for_througput_true)) {
1.305 + action = (char*) " *** throughput goal ***";
1.306 + } else if (decrease_for_footprint()) {
1.307 + action = (char*) " *** reduced footprint ***";
1.308 + } else {
1.309 + // No actions were taken. This can legitimately be the
1.310 + // situation if not enough data has been gathered to make
1.311 + // decisions.
1.312 + return false;
1.313 + }
1.314 +
1.315 + // Pauses
1.316 + // Currently the size of the old gen is only adjusted to
1.317 + // change the major pause times.
1.318 + char* young_gen_action = NULL;
1.319 + char* tenured_gen_action = NULL;
1.320 +
1.321 + char* shrink_msg = (char*) "(attempted to shrink)";
1.322 + char* grow_msg = (char*) "(attempted to grow)";
1.323 + char* no_change_msg = (char*) "(no change)";
1.324 + if (change_young_gen_for_min_pauses() ==
1.325 + decrease_young_gen_for_min_pauses_true) {
1.326 + young_gen_action = shrink_msg;
1.327 + } else if (change_for_pause) {
1.328 + young_gen_action = no_change_msg;
1.329 + }
1.330 +
1.331 + if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) {
1.332 + tenured_gen_action = shrink_msg;
1.333 + } else if (change_for_pause) {
1.334 + tenured_gen_action = no_change_msg;
1.335 + }
1.336 +
1.337 + // Throughput
1.338 + if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) {
1.339 + assert(change_young_gen_for_throughput() ==
1.340 + increase_young_gen_for_througput_true,
1.341 + "Both generations should be growing");
1.342 + young_gen_action = grow_msg;
1.343 + tenured_gen_action = grow_msg;
1.344 + } else if (change_young_gen_for_throughput() ==
1.345 + increase_young_gen_for_througput_true) {
1.346 + // Only the young generation may grow at start up (before
1.347 + // enough full collections have been done to grow the old generation).
1.348 + young_gen_action = grow_msg;
1.349 + tenured_gen_action = no_change_msg;
1.350 + }
1.351 +
1.352 + // Minimum footprint
1.353 + if (decrease_for_footprint() != 0) {
1.354 + young_gen_action = shrink_msg;
1.355 + tenured_gen_action = shrink_msg;
1.356 + }
1.357 +
1.358 + st->print_cr(" UseAdaptiveSizePolicy actions to meet %s", action);
1.359 + st->print_cr(" GC overhead (%%)");
1.360 + st->print_cr(" Young generation: %7.2f\t %s",
1.361 + 100.0 * avg_minor_gc_cost()->average(),
1.362 + young_gen_action);
1.363 + st->print_cr(" Tenured generation: %7.2f\t %s",
1.364 + 100.0 * avg_major_gc_cost()->average(),
1.365 + tenured_gen_action);
1.366 + return true;
1.367 +}
1.368 +
1.369 +bool AdaptiveSizePolicy::print_adaptive_size_policy_on(
1.370 + outputStream* st,
1.371 + int tenuring_threshold_arg) const {
1.372 + if (!AdaptiveSizePolicy::print_adaptive_size_policy_on(st)) {
1.373 + return false;
1.374 + }
1.375 +
1.376 + // Tenuring threshold
1.377 + bool tenuring_threshold_changed = true;
1.378 + if (decrement_tenuring_threshold_for_survivor_limit()) {
1.379 + st->print(" Tenuring threshold: (attempted to decrease to avoid"
1.380 + " survivor space overflow) = ");
1.381 + } else if (decrement_tenuring_threshold_for_gc_cost()) {
1.382 + st->print(" Tenuring threshold: (attempted to decrease to balance"
1.383 + " GC costs) = ");
1.384 + } else if (increment_tenuring_threshold_for_gc_cost()) {
1.385 + st->print(" Tenuring threshold: (attempted to increase to balance"
1.386 + " GC costs) = ");
1.387 + } else {
1.388 + tenuring_threshold_changed = false;
1.389 + assert(!tenuring_threshold_change(), "(no change was attempted)");
1.390 + }
1.391 + if (tenuring_threshold_changed) {
1.392 + st->print_cr("%d", tenuring_threshold_arg);
1.393 + }
1.394 + return true;
1.395 +}
