duke@435: /*
duke@435:  * Copyright 2004-2006 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: #include "incls/_precompiled.incl"
duke@435: #include "incls/_adaptiveSizePolicy.cpp.incl"
duke@435: 
duke@435: elapsedTimer AdaptiveSizePolicy::_minor_timer;
duke@435: elapsedTimer AdaptiveSizePolicy::_major_timer;
duke@435: 
duke@435: // The throughput goal is implemented as
duke@435: //      _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio))
duke@435: // gc_cost_ratio is the ratio
duke@435: //      application cost / gc cost
duke@435: // For example a gc_cost_ratio of 4 translates into a
duke@435: // throughput goal of .80
duke@435: 
duke@435: AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size,
duke@435:                                        size_t init_promo_size,
duke@435:                                        size_t init_survivor_size,
duke@435:                                        double gc_pause_goal_sec,
duke@435:                                        uint gc_cost_ratio) :
duke@435:     _eden_size(init_eden_size),
duke@435:     _promo_size(init_promo_size),
duke@435:     _survivor_size(init_survivor_size),
duke@435:     _gc_pause_goal_sec(gc_pause_goal_sec),
duke@435:     _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))),
duke@435:     _gc_time_limit_exceeded(false),
duke@435:     _print_gc_time_limit_would_be_exceeded(false),
duke@435:     _gc_time_limit_count(0),
duke@435:     _latest_minor_mutator_interval_seconds(0),
duke@435:     _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0),
duke@435:     _young_gen_change_for_minor_throughput(0),
duke@435:     _old_gen_change_for_major_throughput(0) {
duke@435:   _avg_minor_pause    =
duke@435:     new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
duke@435:   _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435:   _avg_minor_gc_cost  = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435:   _avg_major_gc_cost  = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435: 
duke@435:   _avg_young_live     = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
duke@435:   _avg_old_live       = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
duke@435:   _avg_eden_live      = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
duke@435: 
duke@435:   _avg_survived       = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight,
duke@435:                                                   SurvivorPadding);
duke@435:   _avg_pretenured     = new AdaptivePaddedNoZeroDevAverage(
duke@435:                                                   AdaptiveSizePolicyWeight,
duke@435:                                                   SurvivorPadding);
duke@435: 
duke@435:   _minor_pause_old_estimator =
duke@435:     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435:   _minor_pause_young_estimator =
duke@435:     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435:   _minor_collection_estimator =
duke@435:     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435:   _major_collection_estimator =
duke@435:     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435: 
duke@435:   // Start the timers
duke@435:   _minor_timer.start();
duke@435: 
duke@435:   _young_gen_policy_is_ready = false;
duke@435: }
duke@435: 
duke@435: bool AdaptiveSizePolicy::tenuring_threshold_change() const {
duke@435:   return decrement_tenuring_threshold_for_gc_cost() ||
duke@435:          increment_tenuring_threshold_for_gc_cost() ||
duke@435:          decrement_tenuring_threshold_for_survivor_limit();
duke@435: }
duke@435: 
duke@435: void AdaptiveSizePolicy::minor_collection_begin() {
duke@435:   // Update the interval time
duke@435:   _minor_timer.stop();
duke@435:   // Save most recent collection time
duke@435:   _latest_minor_mutator_interval_seconds = _minor_timer.seconds();
duke@435:   _minor_timer.reset();
duke@435:   _minor_timer.start();
duke@435: }
duke@435: 
duke@435: void AdaptiveSizePolicy::update_minor_pause_young_estimator(
duke@435:     double minor_pause_in_ms) {
duke@435:   double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
duke@435:   _minor_pause_young_estimator->update(eden_size_in_mbytes,
duke@435:     minor_pause_in_ms);
duke@435: }
duke@435: 
duke@435: void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) {
duke@435:   // Update the pause time.
duke@435:   _minor_timer.stop();
duke@435: 
duke@435:   if (gc_cause != GCCause::_java_lang_system_gc ||
duke@435:       UseAdaptiveSizePolicyWithSystemGC) {
duke@435:     double minor_pause_in_seconds = _minor_timer.seconds();
duke@435:     double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS;
duke@435: 
duke@435:     // Sample for performance counter
duke@435:     _avg_minor_pause->sample(minor_pause_in_seconds);
duke@435: 
duke@435:     // Cost of collection (unit-less)
duke@435:     double collection_cost = 0.0;
duke@435:     if ((_latest_minor_mutator_interval_seconds > 0.0) &&
duke@435:         (minor_pause_in_seconds > 0.0)) {
duke@435:       double interval_in_seconds =
duke@435:         _latest_minor_mutator_interval_seconds + minor_pause_in_seconds;
duke@435:       collection_cost =
duke@435:         minor_pause_in_seconds / interval_in_seconds;
duke@435:       _avg_minor_gc_cost->sample(collection_cost);
duke@435:       // Sample for performance counter
duke@435:       _avg_minor_interval->sample(interval_in_seconds);
duke@435:     }
duke@435: 
duke@435:     // The policy does not have enough data until at least some
duke@435:     // minor collections have been done.
duke@435:     _young_gen_policy_is_ready =
duke@435:       (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold);
duke@435: 
duke@435:     // Calculate variables used to estimate pause time vs. gen sizes
duke@435:     double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
duke@435:     update_minor_pause_young_estimator(minor_pause_in_ms);
duke@435:     update_minor_pause_old_estimator(minor_pause_in_ms);
duke@435: 
duke@435:     if (PrintAdaptiveSizePolicy && Verbose) {
duke@435:       gclog_or_tty->print("AdaptiveSizePolicy::minor_collection_end: "
duke@435:         "minor gc cost: %f  average: %f", collection_cost,
duke@435:         _avg_minor_gc_cost->average());
duke@435:       gclog_or_tty->print_cr("  minor pause: %f minor period %f",
duke@435:         minor_pause_in_ms,
duke@435:         _latest_minor_mutator_interval_seconds * MILLIUNITS);
duke@435:     }
duke@435: 
duke@435:     // Calculate variable used to estimate collection cost vs. gen sizes
duke@435:     assert(collection_cost >= 0.0, "Expected to be non-negative");
duke@435:     _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost);
duke@435:   }
duke@435: 
duke@435:   // Interval times use this timer to measure the mutator time.
duke@435:   // Reset the timer after the GC pause.
duke@435:   _minor_timer.reset();
duke@435:   _minor_timer.start();
duke@435: }
duke@435: 
duke@435: size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden,
duke@435:                                             uint percent_change) {
duke@435:   size_t eden_heap_delta;
duke@435:   eden_heap_delta = cur_eden / 100 * percent_change;
duke@435:   return eden_heap_delta;
duke@435: }
duke@435: 
duke@435: size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) {
duke@435:   return eden_increment(cur_eden, YoungGenerationSizeIncrement);
duke@435: }
duke@435: 
duke@435: size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
duke@435:   size_t eden_heap_delta = eden_increment(cur_eden) /
duke@435:     AdaptiveSizeDecrementScaleFactor;
duke@435:   return eden_heap_delta;
duke@435: }
duke@435: 
duke@435: size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo,
duke@435:                                              uint percent_change) {
duke@435:   size_t promo_heap_delta;
duke@435:   promo_heap_delta = cur_promo / 100 * percent_change;
duke@435:   return promo_heap_delta;
duke@435: }
duke@435: 
duke@435: size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) {
duke@435:   return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
duke@435: }
duke@435: 
duke@435: size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
duke@435:   size_t promo_heap_delta = promo_increment(cur_promo);
duke@435:   promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
duke@435:   return promo_heap_delta;
duke@435: }
duke@435: 
duke@435: double AdaptiveSizePolicy::time_since_major_gc() const {
duke@435:   _major_timer.stop();
duke@435:   double result = _major_timer.seconds();
duke@435:   _major_timer.start();
duke@435:   return result;
duke@435: }
duke@435: 
duke@435: // Linear decay of major gc cost
duke@435: double AdaptiveSizePolicy::decaying_major_gc_cost() const {
duke@435:   double major_interval = major_gc_interval_average_for_decay();
duke@435:   double major_gc_cost_average = major_gc_cost();
duke@435:   double decayed_major_gc_cost = major_gc_cost_average;
duke@435:   if(time_since_major_gc() > 0.0) {
duke@435:     decayed_major_gc_cost = major_gc_cost() *
duke@435:       (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval)
duke@435:       / time_since_major_gc();
duke@435:   }
duke@435: 
duke@435:   // The decayed cost should always be smaller than the
duke@435:   // average cost but the vagaries of finite arithmetic could
duke@435:   // produce a larger value in decayed_major_gc_cost so protect
duke@435:   // against that.
duke@435:   return MIN2(major_gc_cost_average, decayed_major_gc_cost);
duke@435: }
duke@435: 
duke@435: // Use a value of the major gc cost that has been decayed
duke@435: // by the factor
duke@435: //
duke@435: //      average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale /
duke@435: //        time-since-last-major-gc
duke@435: //
duke@435: // if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale
duke@435: // is less than time-since-last-major-gc.
duke@435: //
duke@435: // In cases where there are initial major gc's that
duke@435: // are of a relatively high cost but no later major
duke@435: // gc's, the total gc cost can remain high because
duke@435: // the major gc cost remains unchanged (since there are no major
duke@435: // gc's).  In such a situation the value of the unchanging
duke@435: // major gc cost can keep the mutator throughput below
duke@435: // the goal when in fact the major gc cost is becoming diminishingly
duke@435: // small.  Use the decaying gc cost only to decide whether to
duke@435: // adjust for throughput.  Using it also to determine the adjustment
duke@435: // to be made for throughput also seems reasonable but there is
duke@435: // no test case to use to decide if it is the right thing to do
duke@435: // don't do it yet.
duke@435: 
duke@435: double AdaptiveSizePolicy::decaying_gc_cost() const {
duke@435:   double decayed_major_gc_cost = major_gc_cost();
duke@435:   double avg_major_interval = major_gc_interval_average_for_decay();
duke@435:   if (UseAdaptiveSizeDecayMajorGCCost &&
duke@435:       (AdaptiveSizeMajorGCDecayTimeScale > 0) &&
duke@435:       (avg_major_interval > 0.00)) {
duke@435:     double time_since_last_major_gc = time_since_major_gc();
duke@435: 
duke@435:     // Decay the major gc cost?
duke@435:     if (time_since_last_major_gc >
duke@435:         ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) {
duke@435: 
duke@435:       // Decay using the time-since-last-major-gc
duke@435:       decayed_major_gc_cost = decaying_major_gc_cost();
duke@435:       if (PrintGCDetails && Verbose) {
duke@435:         gclog_or_tty->print_cr("\ndecaying_gc_cost: major interval average:"
duke@435:           " %f  time since last major gc: %f",
duke@435:           avg_major_interval, time_since_last_major_gc);
duke@435:         gclog_or_tty->print_cr("  major gc cost: %f  decayed major gc cost: %f",
duke@435:           major_gc_cost(), decayed_major_gc_cost);
duke@435:       }
duke@435:     }
duke@435:   }
duke@435:   double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost());
duke@435:   return result;
duke@435: }
duke@435: 
duke@435: 
duke@435: void AdaptiveSizePolicy::clear_generation_free_space_flags() {
duke@435:   set_change_young_gen_for_min_pauses(0);
duke@435:   set_change_old_gen_for_maj_pauses(0);
duke@435: 
duke@435:   set_change_old_gen_for_throughput(0);
duke@435:   set_change_young_gen_for_throughput(0);
duke@435:   set_decrease_for_footprint(0);
duke@435:   set_decide_at_full_gc(0);
duke@435: }
duke@435: 
duke@435: // Printing
duke@435: 
duke@435: bool AdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) const {
duke@435: 
duke@435:   //  Should only be used with adaptive size policy turned on.
duke@435:   // Otherwise, there may be variables that are undefined.
duke@435:   if (!UseAdaptiveSizePolicy) return false;
duke@435: 
duke@435:   // Print goal for which action is needed.
duke@435:   char* action = NULL;
duke@435:   bool change_for_pause = false;
duke@435:   if ((change_old_gen_for_maj_pauses() ==
duke@435:          decrease_old_gen_for_maj_pauses_true) ||
duke@435:       (change_young_gen_for_min_pauses() ==
duke@435:          decrease_young_gen_for_min_pauses_true)) {
duke@435:     action = (char*) " *** pause time goal ***";
duke@435:     change_for_pause = true;
duke@435:   } else if ((change_old_gen_for_throughput() ==
duke@435:                increase_old_gen_for_throughput_true) ||
duke@435:             (change_young_gen_for_throughput() ==
duke@435:                increase_young_gen_for_througput_true)) {
duke@435:     action = (char*) " *** throughput goal ***";
duke@435:   } else if (decrease_for_footprint()) {
duke@435:     action = (char*) " *** reduced footprint ***";
duke@435:   } else {
duke@435:     // No actions were taken.  This can legitimately be the
duke@435:     // situation if not enough data has been gathered to make
duke@435:     // decisions.
duke@435:     return false;
duke@435:   }
duke@435: 
duke@435:   // Pauses
duke@435:   // Currently the size of the old gen is only adjusted to
duke@435:   // change the major pause times.
duke@435:   char* young_gen_action = NULL;
duke@435:   char* tenured_gen_action = NULL;
duke@435: 
duke@435:   char* shrink_msg = (char*) "(attempted to shrink)";
duke@435:   char* grow_msg = (char*) "(attempted to grow)";
duke@435:   char* no_change_msg = (char*) "(no change)";
duke@435:   if (change_young_gen_for_min_pauses() ==
duke@435:       decrease_young_gen_for_min_pauses_true) {
duke@435:     young_gen_action = shrink_msg;
duke@435:   } else if (change_for_pause) {
duke@435:     young_gen_action = no_change_msg;
duke@435:   }
duke@435: 
duke@435:   if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) {
duke@435:     tenured_gen_action = shrink_msg;
duke@435:   } else if (change_for_pause) {
duke@435:     tenured_gen_action = no_change_msg;
duke@435:   }
duke@435: 
duke@435:   // Throughput
duke@435:   if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) {
duke@435:     assert(change_young_gen_for_throughput() ==
duke@435:            increase_young_gen_for_througput_true,
duke@435:            "Both generations should be growing");
duke@435:     young_gen_action = grow_msg;
duke@435:     tenured_gen_action = grow_msg;
duke@435:   } else if (change_young_gen_for_throughput() ==
duke@435:              increase_young_gen_for_througput_true) {
duke@435:     // Only the young generation may grow at start up (before
duke@435:     // enough full collections have been done to grow the old generation).
duke@435:     young_gen_action = grow_msg;
duke@435:     tenured_gen_action = no_change_msg;
duke@435:   }
duke@435: 
duke@435:   // Minimum footprint
duke@435:   if (decrease_for_footprint() != 0) {
duke@435:     young_gen_action = shrink_msg;
duke@435:     tenured_gen_action = shrink_msg;
duke@435:   }
duke@435: 
duke@435:   st->print_cr("    UseAdaptiveSizePolicy actions to meet %s", action);
duke@435:   st->print_cr("                       GC overhead (%%)");
duke@435:   st->print_cr("    Young generation:     %7.2f\t  %s",
duke@435:     100.0 * avg_minor_gc_cost()->average(),
duke@435:     young_gen_action);
duke@435:   st->print_cr("    Tenured generation:   %7.2f\t  %s",
duke@435:     100.0 * avg_major_gc_cost()->average(),
duke@435:     tenured_gen_action);
duke@435:   return true;
duke@435: }
duke@435: 
duke@435: bool AdaptiveSizePolicy::print_adaptive_size_policy_on(
duke@435:                                             outputStream* st,
duke@435:                                             int tenuring_threshold_arg) const {
duke@435:   if (!AdaptiveSizePolicy::print_adaptive_size_policy_on(st)) {
duke@435:     return false;
duke@435:   }
duke@435: 
duke@435:   // Tenuring threshold
duke@435:   bool tenuring_threshold_changed = true;
duke@435:   if (decrement_tenuring_threshold_for_survivor_limit()) {
duke@435:     st->print("    Tenuring threshold:    (attempted to decrease to avoid"
duke@435:               " survivor space overflow) = ");
duke@435:   } else if (decrement_tenuring_threshold_for_gc_cost()) {
duke@435:     st->print("    Tenuring threshold:    (attempted to decrease to balance"
duke@435:               " GC costs) = ");
duke@435:   } else if (increment_tenuring_threshold_for_gc_cost()) {
duke@435:     st->print("    Tenuring threshold:    (attempted to increase to balance"
duke@435:               " GC costs) = ");
duke@435:   } else {
duke@435:     tenuring_threshold_changed = false;
duke@435:     assert(!tenuring_threshold_change(), "(no change was attempted)");
duke@435:   }
duke@435:   if (tenuring_threshold_changed) {
duke@435:     st->print_cr("%d", tenuring_threshold_arg);
duke@435:   }
duke@435:   return true;
duke@435: }