test/loops/LoopHelpers.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/licenses/publicdomain
 */
/**
 * Misc utilities in JSR166 performance tests
 */

import java.util.concurrent.*;
import java.util.concurrent.atomic.*;

class LoopHelpers {

    static final SimpleRandom staticRNG = new SimpleRandom();

    // Some mindless computation to do between synchronizations...

    /**
     * generates 32 bit pseudo-random numbers. 
     * Adapted from http://www.snippets.org
     */
    public static int compute1(int x) { 
        int lo = 16807 * (x & 0xFFFF);
        int hi = 16807 * (x >>> 16);
        lo += (hi & 0x7FFF) << 16;
        if ((lo & 0x80000000) != 0) {
            lo &= 0x7fffffff;
            ++lo;
        }
        lo += hi >>> 15;
        if (lo == 0 || (lo & 0x80000000) != 0) {
            lo &= 0x7fffffff;
            ++lo;
        }
        return lo;
    }

    /**
     *  Computes a linear congruential random number a random number
     *  of times.
     */
    public static int compute2(int x) { 
        int loops = (x >>> 4) & 7;
        while (loops-- > 0) {
            x = (x * 2147483647) % 16807;
        }
        return x;
    }

    /**
     * Yet another random number generator
     */
    public static int compute3(int x) { 
        int t = (x % 127773) * 16807 - (x / 127773) * 2836;
        return (t > 0)? t : t + 0x7fffffff;
    }

    /**
     * Yet another random number generator
     */
    public static int compute4(int x) { 
        return x * 134775813 + 1;
    }


    /**
     * Yet another random number generator
     */
    public static int compute5(int x) { 
        return 36969 * (x & 65535) + (x >> 16);
    }


    /**
     * An actually useful random number generator, but unsynchronized.
     * Basically same as java.util.Random.
     */
    public static class SimpleRandom {
        private final static long multiplier = 0x5DEECE66DL;
        private final static long addend = 0xBL;
        private final static long mask = (1L << 48) - 1;
        static final AtomicLong seq = new AtomicLong(1);
        private long seed = System.nanoTime() + seq.getAndIncrement();

        public void setSeed(long s) {
            seed = s;
        }

        public int next() {
            long nextseed = (seed * multiplier + addend) & mask;
            seed = nextseed;
            return ((int)(nextseed >>> 17)) & 0x7FFFFFFF;
        }
    }

    public static class BarrierTimer implements Runnable {
        public volatile long startTime;
        public volatile long endTime;
        public void run() {
            long t = System.nanoTime();
            if (startTime == 0)
                startTime = t;
            else
                endTime = t;
        }
        public void clear() {
            startTime = 0;
            endTime = 0;
        }
        public long getTime() {
            return endTime - startTime;
        }
    }

    public static String rightJustify(long n) {
        // There's probably a better way to do this...
        String field = "         ";
        String num = Long.toString(n);
        if (num.length() >= field.length())
            return num;
        StringBuffer b = new StringBuffer(field);
        b.replace(b.length()-num.length(), b.length(), num);
        return b.toString();
    }
   
}
Revision:	1.2
Committed:	Mon May 9 19:33:30 2005 UTC (19 years ago) by dl
Branch:	MAIN
Changes since 1.1:	+5 -0 lines
Log Message:	Add headers
#	User	Rev	Content
1	dl	1.2	/*
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	dl	1.1	/**
7			* Misc utilities in JSR166 performance tests
8			*/
9
10			import java.util.concurrent.*;
11			import java.util.concurrent.atomic.*;
12
13			class LoopHelpers {
14
15			static final SimpleRandom staticRNG = new SimpleRandom();
16
17			// Some mindless computation to do between synchronizations...
18
19			/**
20			* generates 32 bit pseudo-random numbers.
21			* Adapted from http://www.snippets.org
22			*/
23			public static int compute1(int x) {
24			int lo = 16807 * (x & 0xFFFF);
25			int hi = 16807 * (x >>> 16);
26			lo += (hi & 0x7FFF) << 16;
27			if ((lo & 0x80000000) != 0) {
28			lo &= 0x7fffffff;
29			++lo;
30			}
31			lo += hi >>> 15;
32			if (lo == 0 \|\| (lo & 0x80000000) != 0) {
33			lo &= 0x7fffffff;
34			++lo;
35			}
36			return lo;
37			}
38
39			/**
40			* Computes a linear congruential random number a random number
41			* of times.
42			*/
43			public static int compute2(int x) {
44			int loops = (x >>> 4) & 7;
45			while (loops-- > 0) {
46			x = (x * 2147483647) % 16807;
47			}
48			return x;
49			}
50
51			/**
52			* Yet another random number generator
53			*/
54			public static int compute3(int x) {
55			int t = (x % 127773) * 16807 - (x / 127773) * 2836;
56			return (t > 0)? t : t + 0x7fffffff;
57			}
58
59			/**
60			* Yet another random number generator
61			*/
62			public static int compute4(int x) {
63			return x * 134775813 + 1;
64			}
65
66
67			/**
68			* Yet another random number generator
69			*/
70			public static int compute5(int x) {
71			return 36969 * (x & 65535) + (x >> 16);
72			}
73
74
75			/**
76			* An actually useful random number generator, but unsynchronized.
77			* Basically same as java.util.Random.
78			*/
79			public static class SimpleRandom {
80			private final static long multiplier = 0x5DEECE66DL;
81			private final static long addend = 0xBL;
82			private final static long mask = (1L << 48) - 1;
83			static final AtomicLong seq = new AtomicLong(1);
84			private long seed = System.nanoTime() + seq.getAndIncrement();
85
86			public void setSeed(long s) {
87			seed = s;
88			}
89
90			public int next() {
91			long nextseed = (seed * multiplier + addend) & mask;
92			seed = nextseed;
93			return ((int)(nextseed >>> 17)) & 0x7FFFFFFF;
94			}
95			}
96
97			public static class BarrierTimer implements Runnable {
98			public volatile long startTime;
99			public volatile long endTime;
100			public void run() {
101			long t = System.nanoTime();
102			if (startTime == 0)
103			startTime = t;
104			else
105			endTime = t;
106			}
107			public void clear() {
108			startTime = 0;
109			endTime = 0;
110			}
111			public long getTime() {
112			return endTime - startTime;
113			}
114			}
115
116			public static String rightJustify(long n) {
117			// There's probably a better way to do this...
118			String field = " ";
119			String num = Long.toString(n);
120			if (num.length() >= field.length())
121			return num;
122			StringBuffer b = new StringBuffer(field);
123			b.replace(b.length()-num.length(), b.length(), num);
124			return b.toString();
125			}
126
127			}