< prev index next >

src/share/vm/gc/g1/g1YoungRemSetSamplingThread.cpp

Print this page
rev 11552 : imported patch 8159978-collection-set-as-array
rev 11553 : imported patch 8159978-erikh-review
rev 11554 : imported patch 8159978-jmasa-review


  54   double vtime_start = os::elapsedVTime();
  55 
  56   while (!should_terminate()) {
  57     sample_young_list_rs_lengths();
  58 
  59     if (os::supports_vtime()) {
  60       _vtime_accum = (os::elapsedVTime() - vtime_start);
  61     } else {
  62       _vtime_accum = 0.0;
  63     }
  64 
  65     sleep_before_next_cycle();
  66   }
  67 }
  68 
  69 void G1YoungRemSetSamplingThread::stop_service() {
  70   MutexLockerEx x(&_monitor, Mutex::_no_safepoint_check_flag);
  71   _monitor.notify();
  72 }
  73 
  74 void G1YoungRemSetSamplingThread::sample_young_list_rs_lengths() {
  75   SuspendibleThreadSetJoiner sts;
  76   G1CollectedHeap* g1h = G1CollectedHeap::heap();
  77   G1Policy* g1p = g1h->g1_policy();
  78   G1CollectionSet* g1cs = g1h->collection_set();
  79   if (g1p->adaptive_young_list_length()) {
  80     int regions_visited = 0;
  81     HeapRegion* hr = g1cs->inc_head();
  82     size_t sampled_rs_lengths = 0;
  83 
  84     while (hr != NULL) {
  85       size_t rs_length = hr->rem_set()->occupied();
  86       sampled_rs_lengths += rs_length;
  87 
  88       // Update the collection set policy information for this region
  89       g1cs->update_young_region_prediction(hr, rs_length);
  90 
  91       ++regions_visited;
  92 
  93       // we try to yield every time we visit 10 regions
  94       if (regions_visited == 10) {
  95         if (sts.should_yield()) {
  96           sts.yield();
  97           // A gc may have occurred and our sampling data is stale and further
  98           // traversal of the collection set is unsafe
  99           return;


 100         }
 101         regions_visited = 0;
 102       }
 103       assert(hr == g1cs->inc_tail() || hr->next_in_collection_set() != NULL, "next should only be null at tail of icset");
 104       hr = hr->next_in_collection_set();















 105     }
 106     g1p->revise_young_list_target_length_if_necessary(sampled_rs_lengths);
 107   }
 108 }


  54   double vtime_start = os::elapsedVTime();
  55 
  56   while (!should_terminate()) {
  57     sample_young_list_rs_lengths();
  58 
  59     if (os::supports_vtime()) {
  60       _vtime_accum = (os::elapsedVTime() - vtime_start);
  61     } else {
  62       _vtime_accum = 0.0;
  63     }
  64 
  65     sleep_before_next_cycle();
  66   }
  67 }
  68 
  69 void G1YoungRemSetSamplingThread::stop_service() {
  70   MutexLockerEx x(&_monitor, Mutex::_no_safepoint_check_flag);
  71   _monitor.notify();
  72 }
  73 
  74 class G1YoungRemSetSamplingClosure : public HeapRegionClosure {
  75   SuspendibleThreadSetJoiner* _sts;
  76   size_t _regions_visited;
  77   size_t _sampled_rs_lengths;
  78 public:
  79   G1YoungRemSetSamplingClosure(SuspendibleThreadSetJoiner* sts) :
  80     HeapRegionClosure(), _sts(sts), _regions_visited(0), _sampled_rs_lengths(0) { }
  81 
  82   virtual bool doHeapRegion(HeapRegion* r) {
  83     size_t rs_length = r->rem_set()->occupied();
  84     _sampled_rs_lengths += rs_length;


  85 
  86     // Update the collection set policy information for this region
  87     G1CollectedHeap::heap()->collection_set()->update_young_region_prediction(r, rs_length);
  88 
  89     _regions_visited++;
  90 
  91     if (_regions_visited == 10) {
  92       if (_sts->should_yield()) {
  93         _sts->yield();

  94         // A gc may have occurred and our sampling data is stale and further
  95         // traversal of the collection set is unsafe
  96         return true;
  97       }
  98       _regions_visited = 0;
  99     }
 100     return false;
 101   }
 102 
 103   size_t sampled_rs_lengths() const { return _sampled_rs_lengths; }
 104 };
 105 
 106 void G1YoungRemSetSamplingThread::sample_young_list_rs_lengths() {
 107   SuspendibleThreadSetJoiner sts;
 108   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 109   G1Policy* g1p = g1h->g1_policy();
 110 
 111   if (g1p->adaptive_young_list_length()) {
 112     G1YoungRemSetSamplingClosure cl(&sts);
 113 
 114     G1CollectionSet* g1cs = g1h->collection_set();
 115     g1cs->iterate(&cl);
 116 
 117     if (cl.complete()) {
 118       g1p->revise_young_list_target_length_if_necessary(cl.sampled_rs_lengths());
 119     }

 120   }
 121 }
< prev index next >