--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/cpu/x86/rdtsc_x86.hpp	Tue May 15 20:24:34 2018 +0200
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef CPU_X86_VM_RDTSC_X86_HPP
+#define CPU_X86_VM_RDTSC_X86_HPP
+
+#include "memory/allocation.hpp"
+#include "utilities/macros.hpp"
+
+// Interface to the x86 rdtsc() time counter, if available.
+// Not guaranteed to be synchronized across hardware threads and
+// therefore software threads, and can be updated asynchronously
+// by software. elapsed_counter() can jump backwards
+// as well as jump forward when threads query different cores/sockets.
+// Very much not recommended for general use.
+// INVTSC is a minimal requirement for auto-enablement.
+
+class Rdtsc : AllStatic {
+ public:
+  static jlong elapsed_counter(); // provides quick time stamps
+  static jlong frequency();       // tsc register
+  static bool  is_supported();    // InvariantTSC
+  static jlong raw();             // direct rdtsc() access
+  static bool  is_elapsed_counter_enabled(); // turn off with -XX:-UseFastUnorderedTimeStamps
+  static jlong epoch();
+  static bool  initialize();
+};
+
+#endif // CPU_X86_VM_RDTSC_X86_HPP