--- /dev/null	2018-06-17 23:18:20.806999507 +0800
+++ new/src/share/classes/jdk/jfr/consumer/TimeConverter.java	2019-01-29 10:59:14.229301278 +0800
@@ -0,0 +1,51 @@
+/*
+ * 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.consumer;
+
+import jdk.jfr.internal.consumer.ChunkHeader;
+
+/**
+ * Converts ticks to nanoseconds
+ */
+final class TimeConverter {
+    private final long startTicks;
+    private final long startNanos;
+    private final double divisor;
+
+    TimeConverter(ChunkHeader chunkHeader) {
+        this.startTicks = chunkHeader.getStartTicks();
+        this.startNanos = chunkHeader.getStartNanos();
+        this.divisor = chunkHeader.getTicksPerSecond() / 1000_000_000L;
+    }
+
+    public long convertTimestamp(long ticks) {
+        return startNanos + (long) ((ticks - startTicks) / divisor);
+    }
+
+    public long convertTimespan(long ticks) {
+        return (long) (ticks / divisor);
+    }
+}