--- old/src/share/vm/gc/shenandoah/shenandoahCollectorPolicy.cpp	2017-05-03 18:44:41.185113585 +0200
+++ new/src/share/vm/gc/shenandoah/shenandoahCollectorPolicy.cpp	2017-05-03 18:44:41.113114839 +0200
@@ -76,6 +76,9 @@
   uint _cancelled_cm_cycles_in_a_row;
   uint _successful_cm_cycles_in_a_row;
 
+  uint _cancelled_uprefs_cycles_in_a_row;
+  uint _successful_uprefs_cycles_in_a_row;
+
   size_t _bytes_in_cset;
 
 public:
@@ -115,6 +118,10 @@
     return _cancelled_cm_cycles_in_a_row <= ShenandoahFullGCThreshold;
   }
 
+  virtual bool handover_cancelled_uprefs() {
+    return _cancelled_uprefs_cycles_in_a_row <= ShenandoahFullGCThreshold;
+  }
+
   virtual void record_cm_cancelled() {
     _cancelled_cm_cycles_in_a_row++;
     _successful_cm_cycles_in_a_row = 0;
@@ -125,6 +132,16 @@
     _successful_cm_cycles_in_a_row++;
   }
 
+  virtual void record_uprefs_cancelled() {
+    _cancelled_uprefs_cycles_in_a_row++;
+    _successful_uprefs_cycles_in_a_row = 0;
+  }
+
+  virtual void record_uprefs_success() {
+    _cancelled_uprefs_cycles_in_a_row = 0;
+    _successful_uprefs_cycles_in_a_row++;
+  }
+
   virtual void record_full_gc() {
     _bytes_in_cset = 0;
   }
@@ -170,6 +187,8 @@
   _bytes_in_cset(0),
   _cancelled_cm_cycles_in_a_row(0),
   _successful_cm_cycles_in_a_row(0),
+  _cancelled_uprefs_cycles_in_a_row(0),
+  _successful_uprefs_cycles_in_a_row(0),
   _region_garbage(NULL),
   _region_garbage_size(0)
 {
@@ -470,24 +489,50 @@
     return r->garbage() > threshold;
   }
 
-  virtual void record_cm_cancelled() {
-    ShenandoahHeuristics::record_cm_cancelled();
+  void optimize_free_threshold() {
+    if (_successful_cm_cycles_in_a_row > 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;
+    }
+  }
+
+  void pessimize_free_threshold() {
     if (_free_threshold < ShenandoahMaxFreeThreshold) {
       _free_threshold++;
       log_info(gc,ergo)("increasing free threshold to: "UINTX_FORMAT, _free_threshold);
     }
   }
 
+  virtual void record_cm_cancelled() {
+    ShenandoahHeuristics::record_cm_cancelled();
+    pessimize_free_threshold();
+  }
+
   virtual void record_cm_success() {
     ShenandoahHeuristics::record_cm_success();
-    if (_successful_cm_cycles_in_a_row > 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;
+    if (update_refs_early()) {
+      optimize_free_threshold();
     }
   }
 
+  virtual void record_uprefs_cancelled() {
+    ShenandoahHeuristics::record_uprefs_cancelled();
+    pessimize_free_threshold();
+  }
+
+  virtual void record_uprefs_success() {
+    ShenandoahHeuristics::record_uprefs_success();
+    optimize_free_threshold();
+  }
+
+  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;
 
@@ -722,7 +767,9 @@
 ShenandoahCollectorPolicy::ShenandoahCollectorPolicy() :
   _cycle_counter(0),
   _successful_cm(0),
-  _degenerated_cm(0)
+  _degenerated_cm(0),
+  _successful_uprefs(0),
+  _degenerated_uprefs(0)
 {
 
   ShenandoahHeapRegion::setup_heap_region_size(initial_heap_byte_size(), max_heap_byte_size());
@@ -947,6 +994,10 @@
   return _heuristics->handover_cancelled_marking();
 }
 
+bool ShenandoahCollectorPolicy::handover_cancelled_uprefs() {
+  return _heuristics->handover_cancelled_uprefs();
+}
+
 bool ShenandoahCollectorPolicy::update_refs_early() {
   return _heuristics->update_refs_early();
 }
@@ -964,6 +1015,19 @@
   _heuristics->record_cm_cancelled();
 }
 
+void ShenandoahCollectorPolicy::record_uprefs_success() {
+  _heuristics->record_uprefs_success();
+  _successful_uprefs++;
+}
+
+void ShenandoahCollectorPolicy::record_uprefs_degenerated() {
+  _degenerated_uprefs++;
+}
+
+void ShenandoahCollectorPolicy::record_uprefs_cancelled() {
+  _heuristics->record_uprefs_cancelled();
+}
+
 void ShenandoahCollectorPolicy::record_full_gc() {
   _heuristics->record_full_gc();
 }
@@ -1002,6 +1066,7 @@
   out->cr();
   out->print_cr("" SIZE_FORMAT " allocation failure and " SIZE_FORMAT " user requested GCs", _allocation_failure_gcs, _user_requested_gcs);
   out->print_cr("" SIZE_FORMAT " successful and " SIZE_FORMAT " degenerated concurrent markings", _successful_cm, _degenerated_cm);
+  out->print_cr("" SIZE_FORMAT " successful and " SIZE_FORMAT " degenerated update references  ", _successful_uprefs, _degenerated_uprefs);
   out->cr();
 }