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Comparing jsr166/src/test/loops/LoopHelpers.java (file contents):
Revision 1.2 by dl, Mon May 9 19:33:30 2005 UTC vs.
Revision 1.14 by jsr166, Thu Jan 15 18:34:19 2015 UTC

# Line 1 | Line 1
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/licenses/publicdomain
5 < */
6 < /**
7 < * Misc utilities in JSR166 performance tests
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 17 | 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 40 | 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 51 | 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  
66 –
66      /**
67       * Yet another random number generator
68       */
69 <    public static int compute5(int x) {
69 >    public static int compute5(int x) {
70          return 36969 * (x & 65535) + (x >> 16);
71      }
72  
73 +    /**
74 +     * Marsaglia xorshift (1, 3, 10)
75 +     */
76 +    public static int compute6(int seed) {
77 +        seed ^= seed << 1;
78 +        seed ^= seed >>> 3;
79 +        seed ^= (seed << 10);
80 +        return seed;
81 +    }
82 +
83 +    /**
84 +     * Marsaglia xorshift (6, 21, 7)
85 +     */
86 +    public static int compute7(int y) {
87 +        y ^= y << 6;
88 +        y ^= y >>> 21;
89 +        y ^= (y << 7);
90 +        return y;
91 +    }
92 +
93 +    // FNV: (x ^ 0x811c9dc5) * 0x01000193;  15485863;
94 +
95 +    /**
96 +     * Marsaglia xorshift for longs
97 +     */
98 +    public static long compute8(long x) {
99 +        x ^= x << 13;
100 +        x ^= x >>> 7;
101 +        x ^= (x << 17);
102 +        return x;
103 +    }
104 +
105 +    public static final class XorShift32Random {
106 +        static final AtomicInteger seq = new AtomicInteger(8862213);
107 +        int x = -1831433054;
108 +        public XorShift32Random(int seed) { x = seed; }
109 +        public XorShift32Random() {
110 +            this((int) System.nanoTime() + seq.getAndAdd(129));
111 +        }
112 +        public int next() {
113 +            x ^= x << 6;
114 +            x ^= x >>> 21;
115 +            x ^= (x << 7);
116 +            return x;
117 +        }
118 +    }
119 +
120 +    /** Multiplication-free RNG from Marsaglia "Xorshift RNGs" paper */
121 +    public static final class MarsagliaRandom {
122 +        static final AtomicInteger seq = new AtomicInteger(3122688);
123 +        int x;
124 +        int y = 842502087;
125 +        int z = -715159705;
126 +        int w = 273326509;
127 +        public MarsagliaRandom(int seed) { x = seed; }
128 +        public MarsagliaRandom() {
129 +            this((int) System.nanoTime() + seq.getAndAdd(129));
130 +        }
131 +        public int next() {
132 +            int t = x ^ (x << 11);
133 +            x = y;
134 +            y = z;
135 +            z = w;
136 +            return w = (w ^ (w >>> 19) ^ (t ^ (t >>> 8)));
137 +        }
138 +    }
139  
140      /**
141 <     * An actually useful random number generator, but unsynchronized.
77 <     * Basically same as java.util.Random.
141 >     * Unsynchronized version of java.util.Random algorithm.
142       */
143 <    public static class SimpleRandom {
144 <        private final static long multiplier = 0x5DEECE66DL;
145 <        private final static long addend = 0xBL;
146 <        private final static long mask = (1L << 48) - 1;
147 <        static final AtomicLong seq = new AtomicLong(1);
148 <        private long seed = System.nanoTime() + seq.getAndIncrement();
143 >    public static final class SimpleRandom {
144 >        private static final long multiplier = 0x5DEECE66DL;
145 >        private static final long addend = 0xBL;
146 >        private static final long mask = (1L << 48) - 1;
147 >        static final AtomicLong seq = new AtomicLong( -715159705);
148 >        private long seed;
149 >
150 >        SimpleRandom(long s) {
151 >            seed = s;
152 >        }
153 >
154 >        SimpleRandom() {
155 >            seed = System.nanoTime() + seq.getAndAdd(129);
156 >        }
157  
158          public void setSeed(long s) {
159              seed = s;
# Line 90 | Line 162 | class LoopHelpers {
162          public int next() {
163              long nextseed = (seed * multiplier + addend) & mask;
164              seed = nextseed;
165 <            return ((int)(nextseed >>> 17)) & 0x7FFFFFFF;
165 >            return ((int) (nextseed >>> 17)) & 0x7FFFFFFF;
166          }
167      }
168  
169      public static class BarrierTimer implements Runnable {
170 <        public volatile long startTime;
171 <        public volatile long endTime;
170 >        volatile boolean started;
171 >        volatile long startTime;
172 >        volatile long endTime;
173          public void run() {
174              long t = System.nanoTime();
175 <            if (startTime == 0)
175 >            if (!started) {
176 >                started = true;
177                  startTime = t;
178 <            else
178 >            } else
179                  endTime = t;
180          }
181          public void clear() {
182 <            startTime = 0;
109 <            endTime = 0;
182 >            started = false;
183          }
184          public long getTime() {
185              return endTime - startTime;
# Line 123 | Line 196 | class LoopHelpers {
196          b.replace(b.length()-num.length(), b.length(), num);
197          return b.toString();
198      }
199 <  
199 >
200   }

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