diff -r 57f1bf06742e -r 8896112226cb src/hotspot/share/gc/z/zArguments.cpp
--- a/src/hotspot/share/gc/z/zArguments.cpp	Tue Aug 28 21:25:37 2018 -0700
+++ b/src/hotspot/share/gc/z/zArguments.cpp	Wed Aug 29 08:00:00 2018 +0200
@@ -76,9 +76,6 @@
   }
 #endif
 
-  // To avoid asserts in set_active_workers()
-  FLAG_SET_DEFAULT(UseDynamicNumberOfGCThreads, true);
-
   // CompressedOops/UseCompressedClassPointers not supported
   FLAG_SET_DEFAULT(UseCompressedOops, false);
   FLAG_SET_DEFAULT(UseCompressedClassPointers, false);