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, 5 months ago) by jsr166
Branch:	MAIN
Log Message:	Add ALoops benchmark to src/loops, target 'loops' already in build.xml
#	Content
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	}