--- old/src/share/vm/gc/parallel/gcTaskThread.cpp	2016-09-23 15:28:41.670168836 +0200
+++ new/src/share/vm/gc/parallel/gcTaskThread.cpp	2016-09-23 15:28:41.510168829 +0200
@@ -58,12 +58,7 @@
   guarantee(index < GCTaskTimeStampEntries, "increase GCTaskTimeStampEntries");
   if (_time_stamps == NULL) {
     // We allocate the _time_stamps array lazily since logging can be enabled dynamically
-    GCTaskTimeStamp* time_stamps = NEW_C_HEAP_ARRAY(GCTaskTimeStamp, GCTaskTimeStampEntries, mtGC);
-    void* old = Atomic::cmpxchg_ptr(time_stamps, &_time_stamps, NULL);
-    if (old != NULL) {
-      // Someone already setup the time stamps
-      FREE_C_HEAP_ARRAY(GCTaskTimeStamp, time_stamps);
-    }
+    _time_stamps = NEW_C_HEAP_ARRAY(GCTaskTimeStamp, GCTaskTimeStampEntries, mtGC);
   }
 
   return &(_time_stamps[index]);
@@ -140,8 +135,6 @@
       // Use the saved value of is_idle_task because references
       // using "task" are not reliable for the barrier task.
       if (!is_idle_task) {
-        manager()->note_completion(which());
-
         if (log_is_enabled(Debug, gc, task, time)) {
           timer.update();
 
@@ -150,11 +143,9 @@
           time_stamp->set_name(name);
           time_stamp->set_entry_time(entry_time);
           time_stamp->set_exit_time(timer.ticks());
-
-          // Update the index after we have set up the entry correctly since
-          // GCTaskThread::print_task_time_stamps() may read this value concurrently.
           _time_stamp_index++;
         }
+        manager()->note_completion(which());
       } else {
         // idle tasks complete outside the normal accounting
         // so that a task can complete without waiting for idle tasks.