src/share/vm/gc/shenandoah/shenandoahCollectorPolicy.cpp

rev 13320 : Use peak occupancy to optimize/pessimize free_threshold in adaptive heuristics.

*** 144,153 ****
--- 144,156 ----
  
    virtual void record_full_gc() {
      _bytes_in_cset = 0;
    }
  
+   virtual void record_peak_occupancy() {
+   }
+ 
    virtual void start_choose_collection_set() {
    }
    virtual void end_choose_collection_set() {
    }
    virtual bool region_in_collection_set(ShenandoahHeapRegion* r, size_t immediate_garbage) = 0;
*** 467,481 ****
  
  class AdaptiveHeuristics : public ShenandoahHeuristics {
  private:
    uintx _free_threshold;
    TruncatedSeq* _cset_history;
! 
  public:
    AdaptiveHeuristics() :
      ShenandoahHeuristics(),
      _free_threshold(ShenandoahInitFreeThreshold),
      _cset_history(new TruncatedSeq((uint)ShenandoahHappyCyclesThreshold)) {
  
      _cset_history->add((double) ShenandoahCSetThreshold);
      _cset_history->add((double) ShenandoahCSetThreshold);
    }
--- 470,485 ----
  
  class AdaptiveHeuristics : public ShenandoahHeuristics {
  private:
    uintx _free_threshold;
    TruncatedSeq* _cset_history;
!   size_t _peak_occupancy;
  public:
    AdaptiveHeuristics() :
      ShenandoahHeuristics(),
      _free_threshold(ShenandoahInitFreeThreshold),
+     _peak_occupancy(0),
      _cset_history(new TruncatedSeq((uint)ShenandoahHappyCyclesThreshold)) {
  
      _cset_history->add((double) ShenandoahCSetThreshold);
      _cset_history->add((double) ShenandoahCSetThreshold);
    }
*** 487,499 ****
    virtual bool region_in_collection_set(ShenandoahHeapRegion* r, size_t immediate_garbage) {
      size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100;
      return r->garbage() > threshold;
    }
  
    void optimize_free_threshold(uint successful_cycles) {
      if (successful_cycles > ShenandoahHappyCyclesThreshold &&
!         _free_threshold > ShenandoahMinFreeThreshold) {
        _free_threshold--;
        log_info(gc,ergo)("reducing free threshold to: "UINTX_FORMAT, _free_threshold);
        _successful_cm_cycles_in_a_row = 0;
      }
    }
--- 491,515 ----
    virtual bool region_in_collection_set(ShenandoahHeapRegion* r, size_t immediate_garbage) {
      size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100;
      return r->garbage() > threshold;
    }
  
+   void handle_gc_success(uint successful_cycles) {
+     ShenandoahHeap* heap = ShenandoahHeap::heap();
+     size_t capacity = heap->capacity();
+     size_t available = heap->capacity() - _peak_occupancy;
+     if (available * 100 / capacity <= ShenandoahMinFreeThreshold) {
+       pessimize_free_threshold();
+     } else {
+       optimize_free_threshold(successful_cycles);
+     }
+     _peak_occupancy = 0;
+   }
+ 
    void optimize_free_threshold(uint successful_cycles) {
      if (successful_cycles > ShenandoahHappyCyclesThreshold &&
!         _free_threshold > 0) {
        _free_threshold--;
        log_info(gc,ergo)("reducing free threshold to: "UINTX_FORMAT, _free_threshold);
        _successful_cm_cycles_in_a_row = 0;
      }
    }
*** 511,539 ****
    }
  
    virtual void record_cm_success() {
      ShenandoahHeuristics::record_cm_success();
      if (! update_refs_early()) {
!       optimize_free_threshold(_successful_cm_cycles_in_a_row);
      }
    }
  
    virtual void record_uprefs_cancelled() {
      ShenandoahHeuristics::record_uprefs_cancelled();
      pessimize_free_threshold();
    }
  
    virtual void record_uprefs_success() {
      ShenandoahHeuristics::record_uprefs_success();
!     optimize_free_threshold(_successful_uprefs_cycles_in_a_row);
    }
  
    virtual void record_full_gc() {
      ShenandoahHeuristics::record_full_gc();
      pessimize_free_threshold();
    }
  
  
    virtual bool should_start_concurrent_mark(size_t used, size_t capacity) const {
      bool shouldStartConcurrentMark = false;
  
      ShenandoahHeap* heap = ShenandoahHeap::heap();
--- 527,558 ----
    }
  
    virtual void record_cm_success() {
      ShenandoahHeuristics::record_cm_success();
      if (! update_refs_early()) {
!       handle_gc_success(_successful_cm_cycles_in_a_row);
      }
    }
  
    virtual void record_uprefs_cancelled() {
      ShenandoahHeuristics::record_uprefs_cancelled();
      pessimize_free_threshold();
    }
  
    virtual void record_uprefs_success() {
      ShenandoahHeuristics::record_uprefs_success();
!     handle_gc_success(_successful_uprefs_cycles_in_a_row);
    }
  
    virtual void record_full_gc() {
      ShenandoahHeuristics::record_full_gc();
      pessimize_free_threshold();
    }
  
+   virtual void record_peak_occupancy() {
+     _peak_occupancy = MAX2(_peak_occupancy, ShenandoahHeap::heap()->used());
+   }
  
    virtual bool should_start_concurrent_mark(size_t used, size_t capacity) const {
      bool shouldStartConcurrentMark = false;
  
      ShenandoahHeap* heap = ShenandoahHeap::heap();
*** 1030,1039 ****
--- 1049,1062 ----
  
  void ShenandoahCollectorPolicy::record_full_gc() {
    _heuristics->record_full_gc();
  }
  
+ void ShenandoahCollectorPolicy::record_peak_occupancy() {
+   _heuristics->record_peak_occupancy();
+ }
+ 
  void ShenandoahCollectorPolicy::choose_collection_set(ShenandoahCollectionSet* collection_set, int* connections) {
    _heuristics->choose_collection_set(collection_set, connections);
  }
  
  void ShenandoahCollectorPolicy::choose_free_set(ShenandoahFreeSet* free_set) {