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Comparing jsr166/src/test/loops/LoopHelpers.java (file contents):
Revision 1.1 by dl, Mon May 2 19:19:38 2005 UTC vs.
Revision 1.13 by jsr166, Sat Feb 16 20:50:29 2013 UTC

# Line 1 | Line 1
1 < /**
2 < * Misc utilities in JSR166 performance tests
1 > /*
2 > * Written by Doug Lea with assistance from members of JCP JSR-166
3 > * Expert Group and released to the public domain, as explained at
4 > * http://creativecommons.org/publicdomain/zero/1.0/
5   */
6  
7   import java.util.concurrent.*;
8   import java.util.concurrent.atomic.*;
9  
10 + /**
11 + * Misc utilities in JSR166 performance tests
12 + */
13   class LoopHelpers {
14  
15      static final SimpleRandom staticRNG = new SimpleRandom();
# Line 12 | Line 17 | class LoopHelpers {
17      // Some mindless computation to do between synchronizations...
18  
19      /**
20 <     * generates 32 bit pseudo-random numbers.
20 >     * generates 32 bit pseudo-random numbers.
21       * Adapted from http://www.snippets.org
22       */
23 <    public static int compute1(int x) {
23 >    public static int compute1(int x) {
24          int lo = 16807 * (x & 0xFFFF);
25          int hi = 16807 * (x >>> 16);
26          lo += (hi & 0x7FFF) << 16;
# Line 35 | Line 40 | class LoopHelpers {
40       *  Computes a linear congruential random number a random number
41       *  of times.
42       */
43 <    public static int compute2(int x) {
43 >    public static int compute2(int x) {
44          int loops = (x >>> 4) & 7;
45          while (loops-- > 0) {
46              x = (x * 2147483647) % 16807;
# Line 46 | Line 51 | class LoopHelpers {
51      /**
52       * Yet another random number generator
53       */
54 <    public static int compute3(int x) {
54 >    public static int compute3(int x) {
55          int t = (x % 127773) * 16807 - (x / 127773) * 2836;
56 <        return (t > 0)? t : t + 0x7fffffff;
56 >        return (t > 0) ? t : t + 0x7fffffff;
57      }
58  
59      /**
60       * Yet another random number generator
61       */
62 <    public static int compute4(int x) {
62 >    public static int compute4(int x) {
63          return x * 134775813 + 1;
64      }
65  
# Line 62 | Line 67 | class LoopHelpers {
67      /**
68       * Yet another random number generator
69       */
70 <    public static int compute5(int x) {
70 >    public static int compute5(int x) {
71          return 36969 * (x & 65535) + (x >> 16);
72      }
73  
74 +    /**
75 +     * Marsaglia xorshift (1, 3, 10)
76 +     */
77 +    public static int compute6(int seed) {
78 +        seed ^= seed << 1;
79 +        seed ^= seed >>> 3;
80 +        seed ^= (seed << 10);
81 +        return seed;
82 +    }
83 +
84 +    /**
85 +     * Marsaglia xorshift (6, 21, 7)
86 +     */
87 +    public static int compute7(int y) {
88 +        y ^= y << 6;
89 +        y ^= y >>> 21;
90 +        y ^= (y << 7);
91 +        return y;
92 +    }
93 +
94 +    // FNV: (x ^ 0x811c9dc5) * 0x01000193;  15485863;
95  
96      /**
97 <     * An actually useful random number generator, but unsynchronized.
72 <     * Basically same as java.util.Random.
97 >     * Marsaglia xorshift for longs
98       */
99 <    public static class SimpleRandom {
100 <        private final static long multiplier = 0x5DEECE66DL;
101 <        private final static long addend = 0xBL;
102 <        private final static long mask = (1L << 48) - 1;
103 <        static final AtomicLong seq = new AtomicLong(1);
104 <        private long seed = System.nanoTime() + seq.getAndIncrement();
99 >    public static long compute8(long x) {
100 >        x ^= x << 13;
101 >        x ^= x >>> 7;
102 >        x ^= (x << 17);
103 >        return x;
104 >    }
105 >
106 >    public static final class XorShift32Random {
107 >        static final AtomicInteger seq = new AtomicInteger(8862213);
108 >        int x = -1831433054;
109 >        public XorShift32Random(int seed) { x = seed; }
110 >        public XorShift32Random() {
111 >            this((int) System.nanoTime() + seq.getAndAdd(129));
112 >        }
113 >        public int next() {
114 >            x ^= x << 6;
115 >            x ^= x >>> 21;
116 >            x ^= (x << 7);
117 >            return x;
118 >        }
119 >    }
120 >
121 >
122 >    /** Multiplication-free RNG from Marsaglia "Xorshift RNGs" paper */
123 >    public static final class MarsagliaRandom {
124 >        static final AtomicInteger seq = new AtomicInteger(3122688);
125 >        int x;
126 >        int y = 842502087;
127 >        int z = -715159705;
128 >        int w = 273326509;
129 >        public MarsagliaRandom(int seed) { x = seed; }
130 >        public MarsagliaRandom() {
131 >            this((int) System.nanoTime() + seq.getAndAdd(129));
132 >        }
133 >        public int next() {
134 >            int t = x ^ (x << 11);
135 >            x = y;
136 >            y = z;
137 >            z = w;
138 >            return w = (w ^ (w >>> 19) ^ (t ^ (t >>> 8)));
139 >        }
140 >    }
141 >
142 >    /**
143 >     * Unsynchronized version of java.util.Random algorithm.
144 >     */
145 >    public static final class SimpleRandom {
146 >        private static final long multiplier = 0x5DEECE66DL;
147 >        private static final long addend = 0xBL;
148 >        private static final long mask = (1L << 48) - 1;
149 >        static final AtomicLong seq = new AtomicLong( -715159705);
150 >        private long seed;
151 >
152 >        SimpleRandom(long s) {
153 >            seed = s;
154 >        }
155 >
156 >        SimpleRandom() {
157 >            seed = System.nanoTime() + seq.getAndAdd(129);
158 >        }
159  
160          public void setSeed(long s) {
161              seed = s;
# Line 85 | Line 164 | class LoopHelpers {
164          public int next() {
165              long nextseed = (seed * multiplier + addend) & mask;
166              seed = nextseed;
167 <            return ((int)(nextseed >>> 17)) & 0x7FFFFFFF;
167 >            return ((int) (nextseed >>> 17)) & 0x7FFFFFFF;
168          }
169      }
170  
171      public static class BarrierTimer implements Runnable {
172 <        public volatile long startTime;
173 <        public volatile long endTime;
172 >        volatile boolean started;
173 >        volatile long startTime;
174 >        volatile long endTime;
175          public void run() {
176              long t = System.nanoTime();
177 <            if (startTime == 0)
177 >            if (!started) {
178 >                started = true;
179                  startTime = t;
180 <            else
180 >            } else
181                  endTime = t;
182          }
183          public void clear() {
184 <            startTime = 0;
104 <            endTime = 0;
184 >            started = false;
185          }
186          public long getTime() {
187              return endTime - startTime;
# Line 118 | Line 198 | class LoopHelpers {
198          b.replace(b.length()-num.length(), b.length(), num);
199          return b.toString();
200      }
201 <  
201 >
202   }

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