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src/hotspot/share/gc/shared/adaptiveSizePolicy.cpp

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rev 52963 : 8212206: Refactor AdaptiveSizePolicy to separate out code related to GC overhead
Summary: Move check_gc_overhead_limit() and related code to its own class
Reviewed-by:


  36 //      _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio))
  37 // gc_cost_ratio is the ratio
  38 //      application cost / gc cost
  39 // For example a gc_cost_ratio of 4 translates into a
  40 // throughput goal of .80
  41 
  42 AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size,
  43                                        size_t init_promo_size,
  44                                        size_t init_survivor_size,
  45                                        double gc_pause_goal_sec,
  46                                        uint gc_cost_ratio) :
  47     _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))),
  48     _eden_size(init_eden_size),
  49     _promo_size(init_promo_size),
  50     _survivor_size(init_survivor_size),
  51     _latest_minor_mutator_interval_seconds(0),
  52     _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0),
  53     _gc_pause_goal_sec(gc_pause_goal_sec),
  54     _young_gen_change_for_minor_throughput(0),
  55     _old_gen_change_for_major_throughput(0) {
  56   assert(AdaptiveSizePolicyGCTimeLimitThreshold > 0,
  57     "No opportunity to clear SoftReferences before GC overhead limit");
  58   _avg_minor_pause    =
  59     new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
  60   _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
  61   _avg_minor_gc_cost  = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
  62   _avg_major_gc_cost  = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
  63 
  64   _avg_young_live     = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
  65   _avg_old_live       = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
  66   _avg_eden_live      = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
  67 
  68   _avg_survived       = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight,
  69                                                   SurvivorPadding);
  70   _avg_pretenured     = new AdaptivePaddedNoZeroDevAverage(
  71                                                   AdaptiveSizePolicyWeight,
  72                                                   SurvivorPadding);
  73 
  74   _minor_pause_old_estimator =
  75     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
  76   _minor_pause_young_estimator =
  77     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);


 256                     avg_major_interval, time_since_last_major_gc);
 257       log_trace(gc, ergo)("  major gc cost: %f  decayed major gc cost: %f",
 258                     major_gc_cost(), decayed_major_gc_cost);
 259     }
 260   }
 261   double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost());
 262   return result;
 263 }
 264 
 265 
 266 void AdaptiveSizePolicy::clear_generation_free_space_flags() {
 267   set_change_young_gen_for_min_pauses(0);
 268   set_change_old_gen_for_maj_pauses(0);
 269 
 270   set_change_old_gen_for_throughput(0);
 271   set_change_young_gen_for_throughput(0);
 272   set_decrease_for_footprint(0);
 273   set_decide_at_full_gc(0);
 274 }
 275 
 276 class AdaptiveSizePolicyTimeOverheadTester: public OverheadTester {
 277   double _gc_cost;
 278 
 279  public:
 280   AdaptiveSizePolicyTimeOverheadTester(double gc_cost) : _gc_cost(gc_cost) {}
 281 
 282   bool is_exceeded() {
 283     // Note that the gc time limit test only works for the collections
 284     // of the young gen + tenured gen and not for collections of the
 285     // permanent gen.  That is because the calculation of the space
 286     // freed by the collection is the free space in the young gen +
 287     // tenured gen.
 288     return _gc_cost > (GCTimeLimit / 100.0);
 289   }
 290 };
 291 
 292 class AdaptiveSizePolicySpaceOverheadTester: public OverheadTester {
 293   size_t _eden_live;
 294   size_t _max_old_gen_size;
 295   size_t _max_eden_size;
 296   size_t _promo_size;
 297   double _avg_eden_live;
 298   double _avg_old_live;
 299 
 300  public:
 301   AdaptiveSizePolicySpaceOverheadTester(size_t eden_live,
 302                                         size_t max_old_gen_size,
 303                                         size_t max_eden_size,
 304                                         size_t promo_size,
 305                                         double avg_eden_live,
 306                                         double avg_old_live) :
 307     _eden_live(eden_live),
 308     _max_old_gen_size(max_old_gen_size),
 309     _max_eden_size(max_eden_size),
 310     _promo_size(promo_size),
 311     _avg_eden_live(avg_eden_live),
 312     _avg_old_live(avg_old_live) {}


 342     size_t promo_limit = (size_t)(_max_old_gen_size - _avg_old_live);
 343     // But don't force a promo size below the current promo size. Otherwise,
 344     // the promo size will shrink for no good reason.
 345     promo_limit = MAX2(promo_limit, _promo_size);
 346 
 347     log_trace(gc, ergo)(
 348           "AdaptiveSizePolicySpaceOverheadTester::is_exceeded:"
 349           " promo_limit: " SIZE_FORMAT
 350           " max_eden_size: " SIZE_FORMAT
 351           " total_free_limit: " SIZE_FORMAT
 352           " max_old_gen_size: " SIZE_FORMAT
 353           " max_eden_size: " SIZE_FORMAT
 354           " mem_free_limit: " SIZE_FORMAT,
 355           promo_limit, _max_eden_size, total_free_limit,
 356           _max_old_gen_size, _max_eden_size,
 357           (size_t)mem_free_limit);
 358 
 359     return free_in_old_gen < (size_t)mem_free_old_limit &&
 360            free_in_eden < (size_t)mem_free_eden_limit;
 361   }
 362 
 363 };
 364 
 365 void AdaptiveSizePolicy::check_gc_overhead_limit(
 366                                           size_t eden_live,
 367                                           size_t max_old_gen_size,
 368                                           size_t max_eden_size,
 369                                           bool   is_full_gc,
 370                                           GCCause::Cause gc_cause,
 371                                           SoftRefPolicy* soft_ref_policy) {
 372 
 373   AdaptiveSizePolicyTimeOverheadTester time_overhead(gc_cost());
 374   AdaptiveSizePolicySpaceOverheadTester space_overhead(eden_live,
 375                                                        max_old_gen_size,
 376                                                        max_eden_size,
 377                                                        _promo_size,
 378                                                        avg_eden_live()->average(),
 379                                                        avg_old_live()->average());
 380   _overhead_checker.check_gc_overhead_limit(&time_overhead,
 381                                             &space_overhead,
 382                                             is_full_gc,




  36 //      _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio))
  37 // gc_cost_ratio is the ratio
  38 //      application cost / gc cost
  39 // For example a gc_cost_ratio of 4 translates into a
  40 // throughput goal of .80
  41 
  42 AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size,
  43                                        size_t init_promo_size,
  44                                        size_t init_survivor_size,
  45                                        double gc_pause_goal_sec,
  46                                        uint gc_cost_ratio) :
  47     _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))),
  48     _eden_size(init_eden_size),
  49     _promo_size(init_promo_size),
  50     _survivor_size(init_survivor_size),
  51     _latest_minor_mutator_interval_seconds(0),
  52     _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0),
  53     _gc_pause_goal_sec(gc_pause_goal_sec),
  54     _young_gen_change_for_minor_throughput(0),
  55     _old_gen_change_for_major_throughput(0) {


  56   _avg_minor_pause    =
  57     new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
  58   _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
  59   _avg_minor_gc_cost  = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
  60   _avg_major_gc_cost  = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
  61 
  62   _avg_young_live     = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
  63   _avg_old_live       = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
  64   _avg_eden_live      = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
  65 
  66   _avg_survived       = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight,
  67                                                   SurvivorPadding);
  68   _avg_pretenured     = new AdaptivePaddedNoZeroDevAverage(
  69                                                   AdaptiveSizePolicyWeight,
  70                                                   SurvivorPadding);
  71 
  72   _minor_pause_old_estimator =
  73     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
  74   _minor_pause_young_estimator =
  75     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);


 254                     avg_major_interval, time_since_last_major_gc);
 255       log_trace(gc, ergo)("  major gc cost: %f  decayed major gc cost: %f",
 256                     major_gc_cost(), decayed_major_gc_cost);
 257     }
 258   }
 259   double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost());
 260   return result;
 261 }
 262 
 263 
 264 void AdaptiveSizePolicy::clear_generation_free_space_flags() {
 265   set_change_young_gen_for_min_pauses(0);
 266   set_change_old_gen_for_maj_pauses(0);
 267 
 268   set_change_old_gen_for_throughput(0);
 269   set_change_young_gen_for_throughput(0);
 270   set_decrease_for_footprint(0);
 271   set_decide_at_full_gc(0);
 272 }
 273 
 274 class AdaptiveSizePolicyTimeOverheadTester: public GCOverheadTester {
 275   double _gc_cost;
 276 
 277  public:
 278   AdaptiveSizePolicyTimeOverheadTester(double gc_cost) : _gc_cost(gc_cost) {}
 279 
 280   bool is_exceeded() {
 281     // Note that the gc time limit test only works for the collections
 282     // of the young gen + tenured gen and not for collections of the
 283     // permanent gen.  That is because the calculation of the space
 284     // freed by the collection is the free space in the young gen +
 285     // tenured gen.
 286     return _gc_cost > (GCTimeLimit / 100.0);
 287   }
 288 };
 289 
 290 class AdaptiveSizePolicySpaceOverheadTester: public GCOverheadTester {
 291   size_t _eden_live;
 292   size_t _max_old_gen_size;
 293   size_t _max_eden_size;
 294   size_t _promo_size;
 295   double _avg_eden_live;
 296   double _avg_old_live;
 297 
 298  public:
 299   AdaptiveSizePolicySpaceOverheadTester(size_t eden_live,
 300                                         size_t max_old_gen_size,
 301                                         size_t max_eden_size,
 302                                         size_t promo_size,
 303                                         double avg_eden_live,
 304                                         double avg_old_live) :
 305     _eden_live(eden_live),
 306     _max_old_gen_size(max_old_gen_size),
 307     _max_eden_size(max_eden_size),
 308     _promo_size(promo_size),
 309     _avg_eden_live(avg_eden_live),
 310     _avg_old_live(avg_old_live) {}


 340     size_t promo_limit = (size_t)(_max_old_gen_size - _avg_old_live);
 341     // But don't force a promo size below the current promo size. Otherwise,
 342     // the promo size will shrink for no good reason.
 343     promo_limit = MAX2(promo_limit, _promo_size);
 344 
 345     log_trace(gc, ergo)(
 346           "AdaptiveSizePolicySpaceOverheadTester::is_exceeded:"
 347           " promo_limit: " SIZE_FORMAT
 348           " max_eden_size: " SIZE_FORMAT
 349           " total_free_limit: " SIZE_FORMAT
 350           " max_old_gen_size: " SIZE_FORMAT
 351           " max_eden_size: " SIZE_FORMAT
 352           " mem_free_limit: " SIZE_FORMAT,
 353           promo_limit, _max_eden_size, total_free_limit,
 354           _max_old_gen_size, _max_eden_size,
 355           (size_t)mem_free_limit);
 356 
 357     return free_in_old_gen < (size_t)mem_free_old_limit &&
 358            free_in_eden < (size_t)mem_free_eden_limit;
 359   }

 360 };
 361 
 362 void AdaptiveSizePolicy::check_gc_overhead_limit(
 363                                           size_t eden_live,
 364                                           size_t max_old_gen_size,
 365                                           size_t max_eden_size,
 366                                           bool   is_full_gc,
 367                                           GCCause::Cause gc_cause,
 368                                           SoftRefPolicy* soft_ref_policy) {
 369 
 370   AdaptiveSizePolicyTimeOverheadTester time_overhead(gc_cost());
 371   AdaptiveSizePolicySpaceOverheadTester space_overhead(eden_live,
 372                                                        max_old_gen_size,
 373                                                        max_eden_size,
 374                                                        _promo_size,
 375                                                        avg_eden_live()->average(),
 376                                                        avg_old_live()->average());
 377   _overhead_checker.check_gc_overhead_limit(&time_overhead,
 378                                             &space_overhead,
 379                                             is_full_gc,


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