--- /dev/null	2018-06-17 23:18:20.806999507 +0800
+++ new/src/share/classes/jdk/jfr/Timespan.java	2019-01-29 10:58:56.743813761 +0800
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2016, 2019, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.
+ */
+
+package jdk.jfr;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Event field annotation, signifies that the value is a duration.
+ *
+ * @since 9
+ */
+@MetadataDefinition
+@ContentType
+@Label("Timespan")
+@Description("A duration, measured in nanoseconds by default")
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.FIELD, ElementType.TYPE, ElementType.METHOD})
+public @interface Timespan {
+    /**
+     * Unit for ticks.
+     */
+    public static final String TICKS = "TICKS";
+    /**
+     * Unit for seconds.
+     */
+    public static final String SECONDS = "SECONDS";
+    /**
+     * Unit for milliseconds.
+     */
+    public static final String MILLISECONDS = "MILLISECONDS";
+    /**
+     * Unit for nanoseconds.
+     */
+    public static final String NANOSECONDS = "NANOSECONDS";
+
+    /**
+     * Unit for microseconds.
+     */
+    public static final String MICROSECONDS = "MICROSECONDS";
+
+    /**
+     * Returns the unit of measure for the time span. By default, the unit is nanoseconds.
+     *
+     * @return the time span unit, default {@code #NANOSECONDS}, not {@code null}
+     */
+    String value() default NANOSECONDS;
+}