--- old/src/hotspot/share/gc/z/zDirector.cpp	2018-03-06 16:38:51.195364645 +0100
+++ new/src/hotspot/share/gc/z/zDirector.cpp	2018-03-06 16:38:51.037357866 +0100
@@ -124,7 +124,7 @@
 
   // Calculate max duration of a GC cycle. The duration of GC is a moving
   // average, we add ~3.3 sigma to account for the GC duration variance.
-  const AbsSeq& duration_of_gc = ZStatCycle::duration();
+  const AbsSeq& duration_of_gc = ZStatCycle::normalized_duration();
   const double max_duration_of_gc = duration_of_gc.davg() + (duration_of_gc.dsd() * one_in_1000);
 
   // Calculate time until GC given the time until OOM and max duration of GC.
@@ -167,7 +167,7 @@
 
   const double assumed_throughput_drop_during_gc = 0.50; // 50%
   const double acceptable_throughput_drop = 0.01;        // 1%
-  const AbsSeq& duration_of_gc = ZStatCycle::duration();
+  const AbsSeq& duration_of_gc = ZStatCycle::normalized_duration();
   const double max_duration_of_gc = duration_of_gc.davg() + (duration_of_gc.dsd() * one_in_1000);
   const double acceptable_gc_interval = max_duration_of_gc * ((assumed_throughput_drop_during_gc / acceptable_throughput_drop) - 1.0);
   const double time_until_gc = acceptable_gc_interval - time_since_last_gc;
--- old/src/hotspot/share/gc/z/zStat.cpp	2018-03-06 16:38:51.453375714 +0100
+++ new/src/hotspot/share/gc/z/zStat.cpp	2018-03-06 16:38:51.292368806 +0100
@@ -1012,7 +1012,7 @@
 uint64_t  ZStatCycle::_ncycles = 0;
 Ticks     ZStatCycle::_start_of_last;
 Ticks     ZStatCycle::_end_of_last;
-NumberSeq ZStatCycle::_duration(0.3 /* alpha */);
+NumberSeq ZStatCycle::_normalized_duration(0.3 /* alpha */);
 
 void ZStatCycle::at_start() {
   _start_of_last = Ticks::now();
@@ -1022,20 +1022,20 @@
   _end_of_last = Ticks::now();
   _ncycles++;
 
-  // Calculate cycle duration. The duration is normalized using the boost
-  // factor to avoid artificial deflation of the duration when boost mode
-  // is enabled.
+  // Calculate normalized cycle duration. The measured duration is
+  // normalized using the boost factor to avoid artificial deflation
+  // of the duration when boost mode is enabled.
   const double duration = TicksToTimeHelper::seconds(_end_of_last - _start_of_last);
   const double normalized_duration = duration * boost_factor;
-  _duration.add(normalized_duration);
+  _normalized_duration.add(normalized_duration);
 }
 
 uint64_t ZStatCycle::ncycles() {
   return _ncycles;
 }
 
-const AbsSeq& ZStatCycle::duration() {
-  return _duration;
+const AbsSeq& ZStatCycle::normalized_duration() {
+  return _normalized_duration;
 }
 
 double ZStatCycle::time_since_last() {
--- old/src/hotspot/share/gc/z/zStat.hpp	2018-03-06 16:38:51.752388542 +0100
+++ new/src/hotspot/share/gc/z/zStat.hpp	2018-03-06 16:38:51.584381334 +0100
@@ -343,14 +343,14 @@
   static uint64_t  _ncycles;
   static Ticks     _start_of_last;
   static Ticks     _end_of_last;
-  static NumberSeq _duration;
+  static NumberSeq _normalized_duration;
 
 public:
   static void at_start();
   static void at_end(double boost_factor);
 
   static uint64_t ncycles();
-  static const AbsSeq& duration();
+  static const AbsSeq& normalized_duration();
   static double time_since_last();
 };