--- a/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/utilities/ProgressiveHeapVisitor.java	Fri Sep 14 14:45:31 2018 +0200
+++ b/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/utilities/ProgressiveHeapVisitor.java	Fri Sep 14 14:44:11 2018 +0200
@@ -50,6 +50,7 @@
     this.usedSize = usedSize;
     visitedSize = 0;
     userHeapVisitor.prologue(usedSize);
+    thunk.heapIterationFractionUpdate(0.0);
   }
 
   public boolean doObj(Oop obj) {