jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/shared/adaptiveSizePolicy.cpp@c18cbe5936b8 (annotated)

src/share/vm/gc_implementation/shared/adaptiveSizePolicy.cpp@c18cbe5936b8 (annotated)

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

Thu, 27 May 2010 19:08:38 -0700

author: trims
date: Thu, 27 May 2010 19:08:38 -0700
changeset 1907: c18cbe5936b8
parent 1822: 0bfd3fb24150
child 2314: f95d63e2154a
permissions: -rw-r--r--

6941466: Oracle rebranding changes for Hotspot repositories
Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair

 /*
  * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "incls/_precompiled.incl"
 #include "incls/_adaptiveSizePolicy.cpp.incl"
 elapsedTimer AdaptiveSizePolicy::_minor_timer;
 elapsedTimer AdaptiveSizePolicy::_major_timer;
 // The throughput goal is implemented as
 //      _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio))
 // gc_cost_ratio is the ratio
 //      application cost / gc cost
 // For example a gc_cost_ratio of 4 translates into a
 // throughput goal of .80
 AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size,
                                        size_t init_promo_size,
                                        size_t init_survivor_size,
                                        double gc_pause_goal_sec,
                                        uint gc_cost_ratio) :
     _eden_size(init_eden_size),
     _promo_size(init_promo_size),
     _survivor_size(init_survivor_size),
     _gc_pause_goal_sec(gc_pause_goal_sec),
     _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))),
     _gc_overhead_limit_exceeded(false),
     _print_gc_overhead_limit_would_be_exceeded(false),
     _gc_overhead_limit_count(0),
     _latest_minor_mutator_interval_seconds(0),
     _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0),
     _young_gen_change_for_minor_throughput(0),
     _old_gen_change_for_major_throughput(0) {
   assert(AdaptiveSizePolicyGCTimeLimitThreshold > 0,
     "No opportunity to clear SoftReferences before GC overhead limit");
   _avg_minor_pause    =
     new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
   _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
   _avg_minor_gc_cost  = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
   _avg_major_gc_cost  = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
   _avg_young_live     = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
   _avg_old_live       = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
   _avg_eden_live      = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
   _avg_survived       = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight,
                                                   SurvivorPadding);
   _avg_pretenured     = new AdaptivePaddedNoZeroDevAverage(
                                                   AdaptiveSizePolicyWeight,
                                                   SurvivorPadding);
   _minor_pause_old_estimator =
     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
   _minor_pause_young_estimator =
     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
   _minor_collection_estimator =
     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
   _major_collection_estimator =
     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
   // Start the timers
   _minor_timer.start();
   _young_gen_policy_is_ready = false;
 }
 bool AdaptiveSizePolicy::tenuring_threshold_change() const {
   return decrement_tenuring_threshold_for_gc_cost() ||
          increment_tenuring_threshold_for_gc_cost() ||
          decrement_tenuring_threshold_for_survivor_limit();
 }
 void AdaptiveSizePolicy::minor_collection_begin() {
   // Update the interval time
   _minor_timer.stop();
   // Save most recent collection time
   _latest_minor_mutator_interval_seconds = _minor_timer.seconds();
   _minor_timer.reset();
   _minor_timer.start();
 }
 void AdaptiveSizePolicy::update_minor_pause_young_estimator(
     double minor_pause_in_ms) {
   double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
   _minor_pause_young_estimator->update(eden_size_in_mbytes,
     minor_pause_in_ms);
 }
 void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) {
   // Update the pause time.
   _minor_timer.stop();
   if (gc_cause != GCCause::_java_lang_system_gc ||
       UseAdaptiveSizePolicyWithSystemGC) {
     double minor_pause_in_seconds = _minor_timer.seconds();
     double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS;
     // Sample for performance counter
     _avg_minor_pause->sample(minor_pause_in_seconds);
     // Cost of collection (unit-less)
     double collection_cost = 0.0;
     if ((_latest_minor_mutator_interval_seconds > 0.0) &&
         (minor_pause_in_seconds > 0.0)) {
       double interval_in_seconds =
         _latest_minor_mutator_interval_seconds + minor_pause_in_seconds;
       collection_cost =
         minor_pause_in_seconds / interval_in_seconds;
       _avg_minor_gc_cost->sample(collection_cost);
       // Sample for performance counter
       _avg_minor_interval->sample(interval_in_seconds);
     }
     // The policy does not have enough data until at least some
     // minor collections have been done.
     _young_gen_policy_is_ready =
       (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold);
     // Calculate variables used to estimate pause time vs. gen sizes
     double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
     update_minor_pause_young_estimator(minor_pause_in_ms);
     update_minor_pause_old_estimator(minor_pause_in_ms);
     if (PrintAdaptiveSizePolicy && Verbose) {
       gclog_or_tty->print("AdaptiveSizePolicy::minor_collection_end: "
         "minor gc cost: %f  average: %f", collection_cost,
         _avg_minor_gc_cost->average());
       gclog_or_tty->print_cr("  minor pause: %f minor period %f",
         minor_pause_in_ms,
         _latest_minor_mutator_interval_seconds * MILLIUNITS);
     }
     // Calculate variable used to estimate collection cost vs. gen sizes
     assert(collection_cost >= 0.0, "Expected to be non-negative");
     _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost);
   }
   // Interval times use this timer to measure the mutator time.
   // Reset the timer after the GC pause.
   _minor_timer.reset();
   _minor_timer.start();
 }
 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden,
                                             uint percent_change) {
   size_t eden_heap_delta;
   eden_heap_delta = cur_eden / 100 * percent_change;
   return eden_heap_delta;
 }
 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) {
   return eden_increment(cur_eden, YoungGenerationSizeIncrement);
 }
 size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
   size_t eden_heap_delta = eden_increment(cur_eden) /
     AdaptiveSizeDecrementScaleFactor;
   return eden_heap_delta;
 }
 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo,
                                              uint percent_change) {
   size_t promo_heap_delta;
   promo_heap_delta = cur_promo / 100 * percent_change;
   return promo_heap_delta;
 }
 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) {
   return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
 }
 size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
   size_t promo_heap_delta = promo_increment(cur_promo);
   promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
   return promo_heap_delta;
 }
 double AdaptiveSizePolicy::time_since_major_gc() const {
   _major_timer.stop();
   double result = _major_timer.seconds();
   _major_timer.start();
   return result;
 }
 // Linear decay of major gc cost
 double AdaptiveSizePolicy::decaying_major_gc_cost() const {
   double major_interval = major_gc_interval_average_for_decay();
   double major_gc_cost_average = major_gc_cost();
   double decayed_major_gc_cost = major_gc_cost_average;
   if(time_since_major_gc() > 0.0) {
     decayed_major_gc_cost = major_gc_cost() *
       (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval)
       / time_since_major_gc();
   }
   // The decayed cost should always be smaller than the
   // average cost but the vagaries of finite arithmetic could
   // produce a larger value in decayed_major_gc_cost so protect
   // against that.
   return MIN2(major_gc_cost_average, decayed_major_gc_cost);
 }
 // Use a value of the major gc cost that has been decayed
 // by the factor
 //
 //      average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale /
 //        time-since-last-major-gc
 //
 // if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale
 // is less than time-since-last-major-gc.
 //
 // In cases where there are initial major gc's that
 // are of a relatively high cost but no later major
 // gc's, the total gc cost can remain high because
 // the major gc cost remains unchanged (since there are no major
 // gc's).  In such a situation the value of the unchanging
 // major gc cost can keep the mutator throughput below
 // the goal when in fact the major gc cost is becoming diminishingly
 // small.  Use the decaying gc cost only to decide whether to
 // adjust for throughput.  Using it also to determine the adjustment
 // to be made for throughput also seems reasonable but there is
 // no test case to use to decide if it is the right thing to do
 // don't do it yet.
 double AdaptiveSizePolicy::decaying_gc_cost() const {
   double decayed_major_gc_cost = major_gc_cost();
   double avg_major_interval = major_gc_interval_average_for_decay();
   if (UseAdaptiveSizeDecayMajorGCCost &&
       (AdaptiveSizeMajorGCDecayTimeScale > 0) &&
       (avg_major_interval > 0.00)) {
     double time_since_last_major_gc = time_since_major_gc();
     // Decay the major gc cost?
     if (time_since_last_major_gc >
         ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) {
       // Decay using the time-since-last-major-gc
       decayed_major_gc_cost = decaying_major_gc_cost();
       if (PrintGCDetails && Verbose) {
         gclog_or_tty->print_cr("\ndecaying_gc_cost: major interval average:"
           " %f  time since last major gc: %f",
           avg_major_interval, time_since_last_major_gc);
         gclog_or_tty->print_cr("  major gc cost: %f  decayed major gc cost: %f",
           major_gc_cost(), decayed_major_gc_cost);
       }
     }
   }
   double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost());
   return result;
 }
 void AdaptiveSizePolicy::clear_generation_free_space_flags() {
   set_change_young_gen_for_min_pauses(0);
   set_change_old_gen_for_maj_pauses(0);
   set_change_old_gen_for_throughput(0);
   set_change_young_gen_for_throughput(0);
   set_decrease_for_footprint(0);
   set_decide_at_full_gc(0);
 }
 void AdaptiveSizePolicy::check_gc_overhead_limit(
                                           size_t young_live,
                                           size_t eden_live,
                                           size_t max_old_gen_size,
                                           size_t max_eden_size,
                                           bool   is_full_gc,
                                           GCCause::Cause gc_cause,
                                           CollectorPolicy* collector_policy) {
   // Ignore explicit GC's.  Exiting here does not set the flag and
   // does not reset the count.  Updating of the averages for system
   // GC's is still controlled by UseAdaptiveSizePolicyWithSystemGC.
   if (GCCause::is_user_requested_gc(gc_cause) ||
       GCCause::is_serviceability_requested_gc(gc_cause)) {
     return;
   }
   // eden_limit is the upper limit on the size of eden based on
   // the maximum size of the young generation and the sizes
   // of the survivor space.
   // The question being asked is whether the gc costs are high
   // and the space being recovered by a collection is low.
   // free_in_young_gen is the free space in the young generation
   // after a collection and promo_live is the free space in the old
   // generation after a collection.
   //
   // Use the minimum of the current value of the live in the
   // young gen or the average of the live in the young gen.
   // If the current value drops quickly, that should be taken
   // into account (i.e., don't trigger if the amount of free
   // space has suddenly jumped up).  If the current is much
   // higher than the average, use the average since it represents
   // the longer term behavor.
   const size_t live_in_eden =
     MIN2(eden_live, (size_t) avg_eden_live()->average());
   const size_t free_in_eden = max_eden_size > live_in_eden ?
     max_eden_size - live_in_eden : 0;
   const size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
   const size_t total_free_limit = free_in_old_gen + free_in_eden;
   const size_t total_mem = max_old_gen_size + max_eden_size;
   const double mem_free_limit = total_mem * (GCHeapFreeLimit/100.0);
   const double mem_free_old_limit = max_old_gen_size * (GCHeapFreeLimit/100.0);
   const double mem_free_eden_limit = max_eden_size * (GCHeapFreeLimit/100.0);
   const double gc_cost_limit = GCTimeLimit/100.0;
   size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average());
   // But don't force a promo size below the current promo size. Otherwise,
   // the promo size will shrink for no good reason.
   promo_limit = MAX2(promo_limit, _promo_size);
   if (PrintAdaptiveSizePolicy && (Verbose ||
       (free_in_old_gen < (size_t) mem_free_old_limit &&
        free_in_eden < (size_t) mem_free_eden_limit))) {
     gclog_or_tty->print_cr(
           "PSAdaptiveSizePolicy::compute_generation_free_space limits:"
           " promo_limit: " SIZE_FORMAT
           " max_eden_size: " SIZE_FORMAT
           " total_free_limit: " SIZE_FORMAT
           " max_old_gen_size: " SIZE_FORMAT
           " max_eden_size: " SIZE_FORMAT
           " mem_free_limit: " SIZE_FORMAT,
           promo_limit, max_eden_size, total_free_limit,
           max_old_gen_size, max_eden_size,
           (size_t) mem_free_limit);
   }
   bool print_gc_overhead_limit_would_be_exceeded = false;
   if (is_full_gc) {
     if (gc_cost() > gc_cost_limit &&
       free_in_old_gen < (size_t) mem_free_old_limit &&
       free_in_eden < (size_t) mem_free_eden_limit) {
       // Collections, on average, are taking too much time, and
       //      gc_cost() > gc_cost_limit
       // we have too little space available after a full gc.
       //      total_free_limit < mem_free_limit
       // where
       //   total_free_limit is the free space available in
       //     both generations
       //   total_mem is the total space available for allocation
       //     in both generations (survivor spaces are not included
       //     just as they are not included in eden_limit).
       //   mem_free_limit is a fraction of total_mem judged to be an
       //     acceptable amount that is still unused.
       // The heap can ask for the value of this variable when deciding
       // whether to thrown an OutOfMemory error.
       // Note that the gc time limit test only works for the collections
       // of the young gen + tenured gen and not for collections of the
       // permanent gen.  That is because the calculation of the space
       // freed by the collection is the free space in the young gen +
       // tenured gen.
       // At this point the GC overhead limit is being exceeded.
       inc_gc_overhead_limit_count();
       if (UseGCOverheadLimit) {
         if (gc_overhead_limit_count() >=
             AdaptiveSizePolicyGCTimeLimitThreshold){
           // All conditions have been met for throwing an out-of-memory
           set_gc_overhead_limit_exceeded(true);
           // Avoid consecutive OOM due to the gc time limit by resetting
           // the counter.
           reset_gc_overhead_limit_count();
         } else {
           // The required consecutive collections which exceed the
           // GC time limit may or may not have been reached. We
           // are approaching that condition and so as not to
           // throw an out-of-memory before all SoftRef's have been
           // cleared, set _should_clear_all_soft_refs in CollectorPolicy.
           // The clearing will be done on the next GC.
           bool near_limit = gc_overhead_limit_near();
           if (near_limit) {
             collector_policy->set_should_clear_all_soft_refs(true);
             if (PrintGCDetails && Verbose) {
               gclog_or_tty->print_cr("  Nearing GC overhead limit, "
                 "will be clearing all SoftReference");
             }
           }
         }
       }
       // Set this even when the overhead limit will not
       // cause an out-of-memory.  Diagnostic message indicating
       // that the overhead limit is being exceeded is sometimes
       // printed.
       print_gc_overhead_limit_would_be_exceeded = true;
     } else {
       // Did not exceed overhead limits
       reset_gc_overhead_limit_count();
     }
   }
   if (UseGCOverheadLimit && PrintGCDetails && Verbose) {
     if (gc_overhead_limit_exceeded()) {
       gclog_or_tty->print_cr("      GC is exceeding overhead limit "
         "of %d%%", GCTimeLimit);
       reset_gc_overhead_limit_count();
     } else if (print_gc_overhead_limit_would_be_exceeded) {
       assert(gc_overhead_limit_count() > 0, "Should not be printing");
       gclog_or_tty->print_cr("      GC would exceed overhead limit "
         "of %d%% %d consecutive time(s)",
         GCTimeLimit, gc_overhead_limit_count());
     }
   }
 }
 // Printing
 bool AdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) const {
   //  Should only be used with adaptive size policy turned on.
   // Otherwise, there may be variables that are undefined.
   if (!UseAdaptiveSizePolicy) return false;
   // Print goal for which action is needed.
   char* action = NULL;
   bool change_for_pause = false;
   if ((change_old_gen_for_maj_pauses() ==
          decrease_old_gen_for_maj_pauses_true) ||
       (change_young_gen_for_min_pauses() ==
          decrease_young_gen_for_min_pauses_true)) {
     action = (char*) " *** pause time goal ***";
     change_for_pause = true;
   } else if ((change_old_gen_for_throughput() ==
                increase_old_gen_for_throughput_true) ||
             (change_young_gen_for_throughput() ==
                increase_young_gen_for_througput_true)) {
     action = (char*) " *** throughput goal ***";
   } else if (decrease_for_footprint()) {
     action = (char*) " *** reduced footprint ***";
   } else {
     // No actions were taken.  This can legitimately be the
     // situation if not enough data has been gathered to make
     // decisions.
     return false;
   }
   // Pauses
   // Currently the size of the old gen is only adjusted to
   // change the major pause times.
   char* young_gen_action = NULL;
   char* tenured_gen_action = NULL;
   char* shrink_msg = (char*) "(attempted to shrink)";
   char* grow_msg = (char*) "(attempted to grow)";
   char* no_change_msg = (char*) "(no change)";
   if (change_young_gen_for_min_pauses() ==
       decrease_young_gen_for_min_pauses_true) {
     young_gen_action = shrink_msg;
   } else if (change_for_pause) {
     young_gen_action = no_change_msg;
   }
   if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) {
     tenured_gen_action = shrink_msg;
   } else if (change_for_pause) {
     tenured_gen_action = no_change_msg;
   }
   // Throughput
   if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) {
     assert(change_young_gen_for_throughput() ==
            increase_young_gen_for_througput_true,
            "Both generations should be growing");
     young_gen_action = grow_msg;
     tenured_gen_action = grow_msg;
   } else if (change_young_gen_for_throughput() ==
              increase_young_gen_for_througput_true) {
     // Only the young generation may grow at start up (before
     // enough full collections have been done to grow the old generation).
     young_gen_action = grow_msg;
     tenured_gen_action = no_change_msg;
   }
   // Minimum footprint
   if (decrease_for_footprint() != 0) {
     young_gen_action = shrink_msg;
     tenured_gen_action = shrink_msg;
   }
   st->print_cr("    UseAdaptiveSizePolicy actions to meet %s", action);
   st->print_cr("                       GC overhead (%%)");
   st->print_cr("    Young generation:     %7.2f\t  %s",
 .0 * avg_minor_gc_cost()->average(),
     young_gen_action);
   st->print_cr("    Tenured generation:   %7.2f\t  %s",
 .0 * avg_major_gc_cost()->average(),
     tenured_gen_action);
   return true;
 }
 bool AdaptiveSizePolicy::print_adaptive_size_policy_on(
                                             outputStream* st,
                                             int tenuring_threshold_arg) const {
   if (!AdaptiveSizePolicy::print_adaptive_size_policy_on(st)) {
     return false;
   }
   // Tenuring threshold
   bool tenuring_threshold_changed = true;
   if (decrement_tenuring_threshold_for_survivor_limit()) {
     st->print("    Tenuring threshold:    (attempted to decrease to avoid"
               " survivor space overflow) = ");
   } else if (decrement_tenuring_threshold_for_gc_cost()) {
     st->print("    Tenuring threshold:    (attempted to decrease to balance"
               " GC costs) = ");
   } else if (increment_tenuring_threshold_for_gc_cost()) {
     st->print("    Tenuring threshold:    (attempted to increase to balance"
               " GC costs) = ");
   } else {
     tenuring_threshold_changed = false;
     assert(!tenuring_threshold_change(), "(no change was attempted)");
   }
   if (tenuring_threshold_changed) {
     st->print_cr("%d", tenuring_threshold_arg);
   }
   return true;
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/shared/adaptiveSizePolicy.cpp@c18cbe5936b8 (annotated)

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