--- old/src/share/vm/runtime/globals.hpp	2015-06-12 14:49:27.373972988 +0200
+++ new/src/share/vm/runtime/globals.hpp	2015-06-12 14:49:27.209967651 +0200
@@ -1451,6 +1451,10 @@
   product(uintx, ParallelGCThreads, 0,                                      \
           "Number of parallel threads parallel gc will use")                \
                                                                             \
+  diagnostic(bool, UseSemaphoreGCThreadsSynchronization, true,              \
+            "Use semaphore synchronization for the GC Threads, "            \
+            "instead of synchronization based on mutexes")                  \
+                                                                            \
   product(bool, UseDynamicNumberOfGCThreads, false,                         \
           "Dynamically choose the number of parallel threads "              \
           "parallel gc will use")                                           \