test/loops/TimeUnitLoops.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
 */
import java.util.concurrent.*;
import java.util.Random;

public class TimeUnitLoops {

    static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();

    /**
     * False value allows aggressive inlining of cvt() calls from
     * test(). True value prevents any inlining, requiring virtual
     * method dispatch.
     */
    static final boolean PREVENT_INLINING = true;

    // The following all are used by inlining prevention clause:
    static int index = 0;
    static final int NUNITS = 100;
    static final TimeUnit[] units = new TimeUnit[NUNITS];
    static {
        TimeUnit[] v = TimeUnit.values();
        for (int i = 0; i < NUNITS; ++i)
            units[i] = v[rng.next() % v.length];
    }

    public static void main(String[] args) throws Exception {
        long start = System.currentTimeMillis();
        long s = 0;
        for (int i = 0; i < 100; ++i) {
            s += test();
            if (s == start) System.out.println(" ");
        }
        long end = System.currentTimeMillis();
        System.out.println("Time: " + (end - start) + " ms");
    }

    static long test() {
        long sum = 0;
        int x = rng.next();
        for (int i = 0; i < 1000000; ++i) {
            long l = (long) x + (long) x;
            sum += cvt(l, TimeUnit.SECONDS);
            sum += TimeUnit.MILLISECONDS.toMicros(l+2);
            sum += cvt(l+17, TimeUnit.NANOSECONDS);
            sum += cvt(l+42, TimeUnit.MILLISECONDS);
            x = LoopHelpers.compute4(x);
        }
        return sum + x;
    }

    static long cvt(long d, TimeUnit u) {
        if (PREVENT_INLINING) {
            u = units[index];
            index = (index+1) % NUNITS;
        }

        return u.toNanos(d);
    }
}
Revision:	1.3
Committed:	Tue Nov 3 01:04:02 2009 UTC (14 years, 6 months ago) by jsr166
Branch:	MAIN
Changes since 1.2:	+1 -1 lines
Log Message:	coding style
#	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	import java.util.concurrent.*;
7			import java.util.Random;
8
9			public class TimeUnitLoops {
10
11			static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
12
13			/**
14			* False value allows aggressive inlining of cvt() calls from
15			* test(). True value prevents any inlining, requiring virtual
16			* method dispatch.
17			*/
18			static final boolean PREVENT_INLINING = true;
19
20			// The following all are used by inlining prevention clause:
21			static int index = 0;
22			static final int NUNITS = 100;
23			static final TimeUnit[] units = new TimeUnit[NUNITS];
24			static {
25			TimeUnit[] v = TimeUnit.values();
26			for (int i = 0; i < NUNITS; ++i)
27			units[i] = v[rng.next() % v.length];
28			}
29
30			public static void main(String[] args) throws Exception {
31			long start = System.currentTimeMillis();
32			long s = 0;
33			for (int i = 0; i < 100; ++i) {
34			s += test();
35			if (s == start) System.out.println(" ");
36			}
37			long end = System.currentTimeMillis();
38			System.out.println("Time: " + (end - start) + " ms");
39			}
40
41			static long test() {
42			long sum = 0;
43			int x = rng.next();
44			for (int i = 0; i < 1000000; ++i) {
45	jsr166	1.3	long l = (long) x + (long) x;
46	dl	1.1	sum += cvt(l, TimeUnit.SECONDS);
47			sum += TimeUnit.MILLISECONDS.toMicros(l+2);
48			sum += cvt(l+17, TimeUnit.NANOSECONDS);
49			sum += cvt(l+42, TimeUnit.MILLISECONDS);
50			x = LoopHelpers.compute4(x);
51			}
52			return sum + x;
53			}
54
55			static long cvt(long d, TimeUnit u) {
56			if (PREVENT_INLINING) {
57			u = units[index];
58			index = (index+1) % NUNITS;
59			}
60
61			return u.toNanos(d);
62			}
63			}