diff -r 13588c901957 -r 9cf78a70fa4f src/hotspot/cpu/zero/globals_zero.hpp
--- a/src/hotspot/cpu/zero/globals_zero.hpp	Thu Oct 17 20:27:44 2019 +0100
+++ b/src/hotspot/cpu/zero/globals_zero.hpp	Thu Oct 17 20:53:35 2019 +0100
@@ -32,8 +32,6 @@
 // Set the default values for platform dependent flags used by the
 // runtime system.  See globals.hpp for details of what they do.
 
-define_pd_global(bool,  ShareVtableStubs,     true);
-
 define_pd_global(bool,  ImplicitNullChecks,   true);
 define_pd_global(bool,  TrapBasedNullChecks,  false);
 define_pd_global(bool,  UncommonNullCast,     true);
@@ -78,7 +76,7 @@
 // No performance work done here yet.
 define_pd_global(bool, CompactStrings, false);
 
-define_pd_global(bool, ThreadLocalHandshakes, false);
+define_pd_global(bool, ThreadLocalHandshakes, true);
 
 #define ARCH_FLAGS(develop, \
                    product, \