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  * @test
  27  * @bug 7177917
  28  * @summary Micro-benchmark for Math.pow() and Math.exp()
  29  * @modules java.base/jdk.internal.misc
  30  * @library /test/lib
  31  *
  32  * @run main compiler.c2.Test7177917
  33  */
  34 
  35 package compiler.c2;
  36 
  37 import jdk.test.lib.Utils;
  38 
  39 import java.util.Random;
  40 
  41 public class Test7177917 {
  42 
  43   static double d;
  44 
  45   static final Random R = Utils.getRandomInstance();
  46 
  47   static long  m_pow(double[][] values) {
  48     double res = 0;
  49     long start = System.nanoTime();
  50     for (int i = 0; i < values.length; i++) {
  51       res += Math.pow(values[i][0], values[i][1]);
  52     }
  53     long stop = System.nanoTime();
  54     d = res;
  55     return (stop - start) / 1000;
  56   }
  57 
  58   static long  m_exp(double[] values) {
  59     double res = 0;
  60     long start = System.nanoTime();
  61     for (int i = 0; i < values.length; i++) {
  62       res += Math.exp(values[i]);
  63     }
  64     long stop = System.nanoTime();
  65     d = res;
  66     return (stop - start) / 1000;
  67   }
  68 
  69   static double[][] pow_values(int nb) {
  70     double[][] res = new double[nb][2];
  71     for (int i = 0; i < nb; i++) {
  72       double ylogx = (1 + (R.nextDouble() * 2045)) - 1023; // 2045 rather than 2046 as a safety margin
  73       double x = Math.abs(Double.longBitsToDouble(R.nextLong()));
  74       while (x != x) {
  75         x = Math.abs(Double.longBitsToDouble(R.nextLong()));
  76       }
  77       double logx = Math.log(x) / Math.log(2);
  78       double y = ylogx / logx;
  79 
  80       res[i][0] = x;
  81       res[i][1] = y;
  82     }
  83     return res;
  84   }
  85 
  86   static double[] exp_values(int nb) {
  87     double[] res = new double[nb];
  88     for (int i = 0; i < nb; i++) {
  89       double ylogx = (1 + (R.nextDouble() * 2045)) - 1023; // 2045 rather than 2046 as a safety margin
  90       double x = Math.E;
  91       double logx = Math.log(x) / Math.log(2);
  92       double y = ylogx / logx;
  93       res[i] = y;
  94     }
  95     return res;
  96   }
  97 
  98   static public void main(String[] args) {
  99     {
 100       // warmup
 101       double[][] warmup_values = pow_values(10);
 102       m_pow(warmup_values);
 103 
 104       for (int i = 0; i < 20000; i++) {
 105         m_pow(warmup_values);
 106       }
 107       // test pow perf
 108       double[][] values = pow_values(1000000);
 109       System.out.println("==> POW " + m_pow(values));
 110 
 111       // force uncommon trap
 112       double[][] nan_values = new double[1][2];
 113       nan_values[0][0] = Double.NaN;
 114       nan_values[0][1] = Double.NaN;
 115       m_pow(nan_values);
 116 
 117       // force recompilation
 118       for (int i = 0; i < 20000; i++) {
 119         m_pow(warmup_values);
 120       }
 121 
 122       // test pow perf again
 123       System.out.println("==> POW " + m_pow(values));
 124     }
 125     {
 126       // warmup
 127       double[] warmup_values = exp_values(10);
 128       m_exp(warmup_values);
 129 
 130       for (int i = 0; i < 20000; i++) {
 131         m_exp(warmup_values);
 132       }
 133 
 134       // test pow perf
 135       double[] values = exp_values(1000000);
 136       System.out.println("==> EXP " + m_exp(values));
 137 
 138       // force uncommon trap
 139       double[] nan_values = new double[1];
 140       nan_values[0] = Double.NaN;
 141       m_exp(nan_values);
 142 
 143       // force recompilation
 144       for (int i = 0; i < 20000; i++) {
 145         m_exp(warmup_values);
 146       }
 147 
 148       // test pow perf again
 149       System.out.println("==> EXP " + m_exp(values));
 150     }
 151   }
 152 }