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