diff -r f87353679927 -r 5d10ba4a0468 src/hotspot/share/gc/z/zStat.cpp
--- a/src/hotspot/share/gc/z/zStat.cpp	Mon Oct 21 14:04:16 2019 +0800
+++ b/src/hotspot/share/gc/z/zStat.cpp	Mon Oct 21 09:51:24 2019 +0200
@@ -1049,6 +1049,14 @@
   _normalized_duration.add(normalized_duration);
 }
 
+bool ZStatCycle::is_first() {
+  return _ncycles == 0;
+}
+
+bool ZStatCycle::is_warm() {
+  return _ncycles >= 3;
+}
+
 uint64_t ZStatCycle::ncycles() {
   return _ncycles;
 }