--- /dev/null	2018-11-30 10:10:44.238550338 +0100
+++ new/src/hotspot/share/gc/shenandoah/shenandoahMetrics.hpp	2018-11-30 10:22:52.107349264 +0100
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2018, Red Hat, Inc. All rights reserved.
+ *
+ * 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 SHARE_VM_GC_SHENANDOAH_SHENANDOAHMETRICS_HPP
+#define SHARE_VM_GC_SHENANDOAH_SHENANDOAHMETRICS_HPP
+
+#include "gc/shenandoah/shenandoahHeap.hpp"
+
+class ShenandoahMetrics {
+private:
+  ShenandoahMetrics() {}
+
+public:
+  static double internal_fragmentation();
+  static double external_fragmentation();
+};
+
+class ShenandoahMetricsSnapshot : public StackObj {
+private:
+  ShenandoahHeap* _heap;
+  size_t _used_before, _used_after;
+  double _if_before, _if_after;
+  double _ef_before, _ef_after;
+
+public:
+  ShenandoahMetricsSnapshot();
+
+  void snap_before();
+  void snap_after();
+  void print();
+
+  bool is_good_progress(const char *label);
+};
+
+#endif //SHARE_VM_GC_SHENANDOAH_SHENANDOAHMETRICS_HPP