1 /*
   2  * Copyright (c) 2012, 2015, 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  */
  24 
  25 /*
  26  * Micro-benchmark for Math.pow() and Math.exp()
  27  */
  28 
  29 import jdk.test.lib.Utils;
  30 import java.util.Random;
  31 
  32 public class Test7177917 {
  33 
  34   static double d;
  35 
  36   static final Random R = Utils.getRandomInstance();
  37 
  38   static long  m_pow(double[][] values) {
  39     double res = 0;
  40     long start = System.nanoTime();
  41     for (int i = 0; i < values.length; i++) {
  42       res += Math.pow(values[i][0], values[i][1]);
  43     }
  44     long stop = System.nanoTime();
  45     d = res;
  46     return (stop - start) / 1000;
  47   }
  48 
  49   static long  m_exp(double[] values) {
  50     double res = 0;
  51     long start = System.nanoTime();
  52     for (int i = 0; i < values.length; i++) {
  53       res += Math.exp(values[i]);
  54     }
  55     long stop = System.nanoTime();
  56     d = res;
  57     return (stop - start) / 1000;
  58   }
  59 
  60   static double[][] pow_values(int nb) {
  61     double[][] res = new double[nb][2];
  62     for (int i = 0; i < nb; i++) {
  63       double ylogx = (1 + (R.nextDouble() * 2045)) - 1023; // 2045 rather than 2046 as a safety margin
  64       double x = Math.abs(Double.longBitsToDouble(R.nextLong()));
  65       while (x != x) {
  66         x = Math.abs(Double.longBitsToDouble(R.nextLong()));
  67       }
  68       double logx = Math.log(x) / Math.log(2);
  69       double y = ylogx / logx;
  70 
  71       res[i][0] = x;
  72       res[i][1] = y;
  73     }
  74     return res;
  75   }
  76 
  77   static double[] exp_values(int nb) {
  78     double[] res = new double[nb];
  79     for (int i = 0; i < nb; i++) {
  80       double ylogx = (1 + (R.nextDouble() * 2045)) - 1023; // 2045 rather than 2046 as a safety margin
  81       double x = Math.E;
  82       double logx = Math.log(x) / Math.log(2);
  83       double y = ylogx / logx;
  84       res[i] = y;
  85     }
  86     return res;
  87   }
  88 
  89   static public void main(String[] args) {
  90     {
  91       // warmup
  92       double[][] warmup_values = pow_values(10);
  93       m_pow(warmup_values);
  94 
  95       for (int i = 0; i < 20000; i++) {
  96         m_pow(warmup_values);
  97       }
  98       // test pow perf
  99       double[][] values = pow_values(1000000);
 100       System.out.println("==> POW " + m_pow(values));
 101 
 102       // force uncommon trap
 103       double[][] nan_values = new double[1][2];
 104       nan_values[0][0] = Double.NaN;
 105       nan_values[0][1] = Double.NaN;
 106       m_pow(nan_values);
 107 
 108       // force recompilation
 109       for (int i = 0; i < 20000; i++) {
 110         m_pow(warmup_values);
 111       }
 112 
 113       // test pow perf again
 114       System.out.println("==> POW " + m_pow(values));
 115     }
 116     {
 117       // warmup
 118       double[] warmup_values = exp_values(10);
 119       m_exp(warmup_values);
 120 
 121       for (int i = 0; i < 20000; i++) {
 122         m_exp(warmup_values);
 123       }
 124 
 125       // test pow perf
 126       double[] values = exp_values(1000000);
 127       System.out.println("==> EXP " + m_exp(values));
 128 
 129       // force uncommon trap
 130       double[] nan_values = new double[1];
 131       nan_values[0] = Double.NaN;
 132       m_exp(nan_values);
 133 
 134       // force recompilation
 135       for (int i = 0; i < 20000; i++) {
 136         m_exp(warmup_values);
 137       }
 138 
 139       // test pow perf again
 140       System.out.println("==> EXP " + m_exp(values));
 141     }
 142   }
 143 }