--- /dev/null	2015-11-16 09:21:03.882507650 +0100
+++ new/src/share/vm/gc/g1/g1InitialMarkToMixedTimeTracker.hpp	2015-11-16 16:53:04.847413822 +0100
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2001, 2015, 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 SHARE_VM_GC_G1_G1INITIALMARKTOMIXEDTIMETRACKER_HPP
+#define SHARE_VM_GC_G1_G1INITIALMARKTOMIXEDTIMETRACKER_HPP
+
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/debug.hpp"
+
+// Used to track time from the end of initial mark to the first mixed GC.
+// After calling the initial mark/mixed gc notifications, the result can be
+// obtained in last_marking_time() once, after which the tracking resets.
+// Any pauses recorded by add_pause() will be subtracted from that results.
+class G1InitialMarkToMixedTimeTracker VALUE_OBJ_CLASS_SPEC {
+private:
+  bool _active;
+  double _initial_mark_end_time;
+  double _mixed_start_time;
+  double _total_pause_time;
+
+  double wall_time() const {
+    return _mixed_start_time - _initial_mark_end_time;
+  }
+public:
+  G1InitialMarkToMixedTimeTracker() { reset(); }
+
+  // Record initial mark pause end, starting the time tracking.
+  void record_initial_mark_end(double end_time) {
+    assert(!_active, "Initial mark out of order.");
+    _initial_mark_end_time = end_time;
+    _active = true;
+  }
+
+  // Record the first mixed gc pause start, ending the time tracking.
+  void record_mixed_gc_start(double start_time) {
+    if (_active) {
+      _mixed_start_time = start_time;
+      _active = false;
+    }
+  }
+
+  double last_marking_time() {
+    assert(has_result(), "Do not have all measurements yet.");
+    double result = (_mixed_start_time - _initial_mark_end_time) - _total_pause_time;
+    reset();
+    return result;
+  }
+
+  void reset() {
+    _active = false;
+    _total_pause_time = 0.0;
+    _initial_mark_end_time = -1.0;
+    _mixed_start_time = -1.0;
+  }
+
+  void add_pause(double time) {
+    if (_active) {
+      _total_pause_time += time;
+    }
+  }
+
+  // Returns whether we have a result that can be retrieved.
+  bool has_result() const { return _mixed_start_time > 0.0 && _initial_mark_end_time > 0.0; }
+};
+
+#endif // SHARE_VM_GC_G1_G1INITIALMARKTOMIXEDTIMETRACKER_HPP