1 /* 2 * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.graalvm.compiler.debug; 24 25 import java.lang.management.ThreadMXBean; 26 27 /** 28 * A consistent source of timing data that should be used by all facilities in the debug package. 29 */ 30 public class TimeSource { 31 private static final boolean USING_BEAN; 32 private static final ThreadMXBean threadMXBean; 33 34 static { 35 threadMXBean = Management.getThreadMXBean(); 36 if (threadMXBean.isThreadCpuTimeSupported()) { 37 USING_BEAN = true; 38 } else { 39 USING_BEAN = false; 40 } 41 } 42 43 /** 44 * Gets the current time of this thread in nanoseconds from the most accurate timer available on 45 * the system. The returned value will be the current time in nanoseconds precision but not 46 * necessarily nanoseconds accuracy. 47 * <p> 48 * The intended use case of this method is to measure the time a certain action takes by making 49 * successive calls to it. It should not be used to measure total times in the sense of a time 50 * stamp. 51 * 52 * @return the current thread's time in nanoseconds 53 */ 54 public static long getTimeNS() { 55 return USING_BEAN ? threadMXBean.getCurrentThreadCpuTime() : System.nanoTime(); 56 } 57 58 }