src/loops/LoopHelpers.java

/**
 * 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;
    }

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

    /**
     * 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:	1.1
Committed:	Fri Apr 9 20:12:06 2004 UTC (20 years, 2 months ago) by jsr166
Branch:	MAIN
Log Message:	Add ALoops benchmark to src/loops, target 'loops' already in build.xml
#	User	Rev	Content
1	jsr166	1.1	/**
2			* Misc utilities in JSR166 performance tests
3			*/
4
5			import java.util.concurrent.*;
6			import java.util.concurrent.atomic.*;
7
8			class LoopHelpers {
9
10			static final SimpleRandom staticRNG = new SimpleRandom();
11
12			// Some mindless computation to do between synchronizations...
13
14			/**
15			* generates 32 bit pseudo-random numbers.
16			* Adapted from http://www.snippets.org
17			*/
18			public static int compute1(int x) {
19			int lo = 16807 * (x & 0xFFFF);
20			int hi = 16807 * (x >>> 16);
21			lo += (hi & 0x7FFF) << 16;
22			if ((lo & 0x80000000) != 0) {
23			lo &= 0x7fffffff;
24			++lo;
25			}
26			lo += hi >>> 15;
27			if (lo == 0 \|\| (lo & 0x80000000) != 0) {
28			lo &= 0x7fffffff;
29			++lo;
30			}
31			return lo;
32			}
33
34			/**
35			* Computes a linear congruential random number a random number
36			* of times.
37			*/
38			public static int compute2(int x) {
39			int loops = (x >>> 4) & 7;
40			while (loops-- > 0) {
41			x = (x * 2147483647) % 16807;
42			}
43			return x;
44			}
45
46			public static int compute3(int x) {
47			int t = (x % 127773) * 16807 - (x / 127773) * 2836;
48			return (t > 0)? t : t + 0x7fffffff;
49			}
50
51			/**
52			* An actually useful random number generator, but unsynchronized.
53			* Basically same as java.util.Random.
54			*/
55			public static class SimpleRandom {
56			private final static long multiplier = 0x5DEECE66DL;
57			private final static long addend = 0xBL;
58			private final static long mask = (1L << 48) - 1;
59			static final AtomicLong seq = new AtomicLong(1);
60			private long seed = System.nanoTime() + seq.getAndIncrement();
61
62			public void setSeed(long s) {
63			seed = s;
64			}
65
66			public int next() {
67			long nextseed = (seed * multiplier + addend) & mask;
68			seed = nextseed;
69			return ((int)(nextseed >>> 17)) & 0x7FFFFFFF;
70			}
71			}
72
73			public static class BarrierTimer implements Runnable {
74			public volatile long startTime;
75			public volatile long endTime;
76			public void run() {
77			long t = System.nanoTime();
78			if (startTime == 0)
79			startTime = t;
80			else
81			endTime = t;
82			}
83			public void clear() {
84			startTime = 0;
85			endTime = 0;
86			}
87			public long getTime() {
88			return endTime - startTime;
89			}
90			}
91
92			public static String rightJustify(long n) {
93			// There's probably a better way to do this...
94			String field = " ";
95			String num = Long.toString(n);
96			if (num.length() >= field.length())
97			return num;
98			StringBuffer b = new StringBuffer(field);
99			b.replace(b.length()-num.length(), b.length(), num);
100			return b.toString();
101			}
102
103			}