1 /*
   2  * Copyright (c) 2007, 2012, 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.jtt.jdk;
  24 
  25 import org.junit.Test;
  26 
  27 import org.graalvm.compiler.jtt.JTTTest;
  28 
  29 /*
  30  */
  31 public class System_nanoTime02 extends JTTTest {
  32 
  33     public static boolean test() {
  34         long minDelta = Long.MAX_VALUE;
  35 
  36         // the first call to System.nanoTime might take a long time due to call resolution
  37         for (int c = 0; c < 10; c++) {
  38             long start = System.nanoTime();
  39             long delta = 0;
  40             int i;
  41             for (i = 0; delta == 0 && i < 50000; i++) {
  42                 delta = System.nanoTime() - start;
  43                 // do nothing.
  44             }
  45             if (delta < minDelta) {
  46                 minDelta = delta;
  47             }
  48         }
  49 
  50         // better get at least 30 microsecond resolution.
  51         return minDelta > 1 && minDelta < 30000;
  52     }
  53 
  54     @Test
  55     public void run0() throws Throwable {
  56         runTest("test");
  57     }
  58 
  59 }