1 /*
   2  * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc/g1/g1CollectedHeap.inline.hpp"
  27 #include "gc/g1/g1IHOPControl.hpp"
  28 #include "gc/g1/g1Predictions.hpp"
  29 #include "gc/shared/gcTrace.hpp"
  30 #include "logging/log.hpp"
  31 
  32 G1IHOPControl::G1IHOPControl(double initial_ihop_percent) :
  33   _initial_ihop_percent(initial_ihop_percent),
  34   _target_occupancy(0),
  35   _last_allocation_time_s(0.0),
  36   _last_allocated_bytes(0)
  37 {
  38   assert(_initial_ihop_percent >= 0.0 && _initial_ihop_percent <= 100.0, "Initial IHOP value must be between 0 and 100 but is %.3f", initial_ihop_percent);
  39 }
  40 
  41 void G1IHOPControl::update_target_occupancy(size_t new_target_occupancy) {
  42   log_debug(gc, ihop)("Target occupancy update: old: " SIZE_FORMAT "B, new: " SIZE_FORMAT "B",
  43                       _target_occupancy, new_target_occupancy);
  44   _target_occupancy = new_target_occupancy;
  45 }
  46 
  47 void G1IHOPControl::update_allocation_info(double allocation_time_s, size_t allocated_bytes, size_t additional_buffer_size) {
  48   assert(allocation_time_s >= 0.0, "Allocation time must be positive but is %.3f", allocation_time_s);
  49 
  50   _last_allocation_time_s = allocation_time_s;
  51   _last_allocated_bytes = allocated_bytes;
  52 }
  53 
  54 void G1IHOPControl::print() {
  55   assert(_target_occupancy > 0, "Target occupancy still not updated yet.");
  56   size_t cur_conc_mark_start_threshold = get_conc_mark_start_threshold();
  57   log_debug(gc, ihop)("Basic information (value update), threshold: " SIZE_FORMAT "B (%1.2f), target occupancy: " SIZE_FORMAT "B, current occupancy: " SIZE_FORMAT "B, "
  58                       "recent allocation size: " SIZE_FORMAT "B, recent allocation duration: %1.2fms, recent old gen allocation rate: %1.2fB/s, recent marking phase length: %1.2fms",
  59                       cur_conc_mark_start_threshold,
  60                       percent_of(cur_conc_mark_start_threshold, _target_occupancy),
  61                       _target_occupancy,
  62                       G1CollectedHeap::heap()->used(),
  63                       _last_allocated_bytes,
  64                       _last_allocation_time_s * 1000.0,
  65                       _last_allocation_time_s > 0.0 ? _last_allocated_bytes / _last_allocation_time_s : 0.0,
  66                       last_marking_length_s() * 1000.0);
  67 }
  68 
  69 void G1IHOPControl::send_trace_event(G1NewTracer* tracer) {
  70   assert(_target_occupancy > 0, "Target occupancy still not updated yet.");
  71   tracer->report_basic_ihop_statistics(get_conc_mark_start_threshold(),
  72                                        _target_occupancy,
  73                                        G1CollectedHeap::heap()->used(),
  74                                        _last_allocated_bytes,
  75                                        _last_allocation_time_s,
  76                                        last_marking_length_s());
  77 }
  78 
  79 G1StaticIHOPControl::G1StaticIHOPControl(double ihop_percent) :
  80   G1IHOPControl(ihop_percent),
  81   _last_marking_length_s(0.0) {
  82 }
  83 
  84 G1AdaptiveIHOPControl::G1AdaptiveIHOPControl(double ihop_percent,
  85                                              G1Predictions const* predictor,
  86                                              size_t heap_reserve_percent,
  87                                              size_t heap_waste_percent) :
  88   G1IHOPControl(ihop_percent),
  89   _heap_reserve_percent(heap_reserve_percent),
  90   _heap_waste_percent(heap_waste_percent),
  91   _predictor(predictor),
  92   _marking_times_s(10, 0.95),
  93   _allocation_rate_s(10, 0.95),
  94   _last_unrestrained_young_size(0)
  95 {
  96 }
  97 
  98 size_t G1AdaptiveIHOPControl::actual_target_threshold() const {
  99   guarantee(_target_occupancy > 0, "Target occupancy still not updated yet.");
 100   // The actual target threshold takes the heap reserve and the expected waste in
 101   // free space  into account.
 102   // _heap_reserve is that part of the total heap capacity that is reserved for
 103   // eventual promotion failure.
 104   // _heap_waste is the amount of space will never be reclaimed in any
 105   // heap, so can not be used for allocation during marking and must always be
 106   // considered.
 107 
 108   double safe_total_heap_percentage = MIN2((double)(_heap_reserve_percent + _heap_waste_percent), 100.0);
 109 
 110   return (size_t)MIN2(
 111     G1CollectedHeap::heap()->max_capacity() * (100.0 - safe_total_heap_percentage) / 100.0,
 112     _target_occupancy * (100.0 - _heap_waste_percent) / 100.0
 113     );
 114 }
 115 
 116 bool G1AdaptiveIHOPControl::have_enough_data_for_prediction() const {
 117   return ((size_t)_marking_times_s.num() >= G1AdaptiveIHOPNumInitialSamples) &&
 118          ((size_t)_allocation_rate_s.num() >= G1AdaptiveIHOPNumInitialSamples);
 119 }
 120 
 121 size_t G1AdaptiveIHOPControl::get_conc_mark_start_threshold() {
 122   if (have_enough_data_for_prediction()) {
 123     double pred_marking_time = _predictor->get_new_prediction(&_marking_times_s);
 124     double pred_promotion_rate = _predictor->get_new_prediction(&_allocation_rate_s);
 125     size_t pred_promotion_size = (size_t)(pred_marking_time * pred_promotion_rate);
 126 
 127     size_t predicted_needed_bytes_during_marking =
 128       pred_promotion_size +
 129       // In reality we would need the maximum size of the young gen during
 130       // marking. This is a conservative estimate.
 131       _last_unrestrained_young_size;
 132 
 133     size_t internal_threshold = actual_target_threshold();
 134     size_t predicted_initiating_threshold = predicted_needed_bytes_during_marking < internal_threshold ?
 135                                             internal_threshold - predicted_needed_bytes_during_marking :
 136                                             0;
 137     return predicted_initiating_threshold;
 138   } else {
 139     // Use the initial value.
 140     return (size_t)(_initial_ihop_percent * _target_occupancy / 100.0);
 141   }
 142 }
 143 
 144 void G1AdaptiveIHOPControl::update_allocation_info(double allocation_time_s,
 145                                                    size_t allocated_bytes,
 146                                                    size_t additional_buffer_size) {
 147   G1IHOPControl::update_allocation_info(allocation_time_s, allocated_bytes, additional_buffer_size);
 148 
 149   double allocation_rate = (double) allocated_bytes / allocation_time_s;
 150   _allocation_rate_s.add(allocation_rate);
 151 
 152   _last_unrestrained_young_size = additional_buffer_size;
 153 }
 154 
 155 void G1AdaptiveIHOPControl::update_marking_length(double marking_length_s) {
 156    assert(marking_length_s >= 0.0, "Marking length must be larger than zero but is %.3f", marking_length_s);
 157   _marking_times_s.add(marking_length_s);
 158 }
 159 
 160 void G1AdaptiveIHOPControl::print() {
 161   G1IHOPControl::print();
 162   size_t actual_target = actual_target_threshold();
 163   log_debug(gc, ihop)("Adaptive IHOP information (value update), threshold: " SIZE_FORMAT "B (%1.2f), internal target occupancy: " SIZE_FORMAT "B, "
 164                       "occupancy: " SIZE_FORMAT "B, additional buffer size: " SIZE_FORMAT "B, predicted old gen allocation rate: %1.2fB/s, "
 165                       "predicted marking phase length: %1.2fms, prediction active: %s",
 166                       get_conc_mark_start_threshold(),
 167                       percent_of(get_conc_mark_start_threshold(), actual_target),
 168                       actual_target,
 169                       G1CollectedHeap::heap()->used(),
 170                       _last_unrestrained_young_size,
 171                       _predictor->get_new_prediction(&_allocation_rate_s),
 172                       _predictor->get_new_prediction(&_marking_times_s) * 1000.0,
 173                       have_enough_data_for_prediction() ? "true" : "false");
 174 }
 175 
 176 void G1AdaptiveIHOPControl::send_trace_event(G1NewTracer* tracer) {
 177   G1IHOPControl::send_trace_event(tracer);
 178   tracer->report_adaptive_ihop_statistics(get_conc_mark_start_threshold(),
 179                                           actual_target_threshold(),
 180                                           G1CollectedHeap::heap()->used(),
 181                                           _last_unrestrained_young_size,
 182                                           _predictor->get_new_prediction(&_allocation_rate_s),
 183                                           _predictor->get_new_prediction(&_marking_times_s),
 184                                           have_enough_data_for_prediction());
 185 }