test/loops/DynamicLeftSpineFib.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/publicdomain/zero/1.0/
 */

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

public final class DynamicLeftSpineFib extends RecursiveAction {

    static long lastStealCount;

    public static void main(String[] args) throws Exception {
        int procs = 0;
        int num = 45;
        try {
            if (args.length > 0)
                procs = Integer.parseInt(args[0]);
            if (args.length > 1)
                num = Integer.parseInt(args[1]);
        }
        catch (Exception e) {
            System.out.println("Usage: java DynamicLeftSpineFib <threads> <number> [<sequntialThreshold>]");
            return;
        }

        for (int reps = 0; reps < 2; ++reps) {
            ForkJoinPool g = (procs == 0) ? new ForkJoinPool() :
                new ForkJoinPool(procs);
            lastStealCount = g.getStealCount();
            for (int i = 0; i < 20; ++i) {
                test(g, num);
            }
            System.out.println(g);
            g.shutdown();
            if (!g.awaitTermination(10, TimeUnit.SECONDS))
                throw new Error();
            Thread.sleep(1000);
        }
    }

    static void test(ForkJoinPool g, int num) throws Exception {
        int ps = g.getParallelism();
        long start = System.currentTimeMillis();
        DynamicLeftSpineFib f = new DynamicLeftSpineFib(num, null);
        g.invoke(f);
        long time = System.currentTimeMillis() - start;
        double secs = ((double)time) / 1000.0;
        long result = f.getAnswer();
        System.out.print("DLSFib " + num + " = " + result);
        System.out.printf("\tTime: %7.3f", secs);
        long sc = g.getStealCount();
        long ns = sc - lastStealCount;
        lastStealCount = sc;
        System.out.printf(" Steals/t: %5d", ns/ps);
        System.out.printf(" Workers: %8d", g.getPoolSize());
        System.out.println();
    }

    // Initialized with argument; replaced with result
    int number;
    DynamicLeftSpineFib next;

    DynamicLeftSpineFib(int n, DynamicLeftSpineFib nxt) {
        number = n; next = nxt;
    }

    int getAnswer() {
        return number;
    }
    public void compute() {
        number = fib(number);
    }

    static final int fib(int n) {
        if (n <= 1)
            return n;
        int r = 0;
        DynamicLeftSpineFib rt = null;
        while (getSurplusQueuedTaskCount() <= 3) {
            int m = n - 2;
            n -= 1;
            if (m <= 1) {
                r += m;
                if (n > 1) {
                    r += n - 2;
                    n -= 1;
                }
                break;
            }
            (rt = new DynamicLeftSpineFib(m, rt)).fork();
        }
        if (n <= 1)
            r += n;
        else
            r += seqFib(n - 2) + fib(n - 1);
        if (rt != null)
            r += collectRights(rt);
        return r;
    }

    static final int collectRights(DynamicLeftSpineFib rt) {
        int r = 0;
        while (rt != null) {
            DynamicLeftSpineFib rn = rt.next;
            rt.next = null;
            if (rt.tryUnfork())
                r += fib(rt.number);
            else {
                rt.join();
                r += rt.number;
            }
            rt = rn;
        }
        return r;
    }

    // Sequential version for arguments less than threshold
    static final int seqFib(int n) { // unroll left only
        int r = 1;
        do {
            int m = n - 2;
            r += m <= 1 ? m : seqFib(m);
        } while (--n > 1);
        return r;
    }

}
Revision:	1.16
Committed:	Thu Jan 15 18:34:19 2015 UTC (9 years, 4 months ago) by jsr166
Branch:	MAIN
Changes since 1.15:	+0 -2 lines
Log Message:	delete extraneous blank lines
#	User	Rev	Content
1	jsr166	1.14	/*
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/publicdomain/zero/1.0/
5			*/
6
7	jsr166	1.15	import java.util.*;
8	dl	1.10	import java.util.concurrent.*;
9	dl	1.1
10			public final class DynamicLeftSpineFib extends RecursiveAction {
11
12			static long lastStealCount;
13	jsr166	1.11
14	dl	1.1	public static void main(String[] args) throws Exception {
15			int procs = 0;
16	dl	1.10	int num = 45;
17	dl	1.1	try {
18			if (args.length > 0)
19			procs = Integer.parseInt(args[0]);
20			if (args.length > 1)
21			num = Integer.parseInt(args[1]);
22			}
23			catch (Exception e) {
24	dl	1.7	System.out.println("Usage: java DynamicLeftSpineFib <threads> <number> [<sequntialThreshold>]");
25	dl	1.1	return;
26			}
27
28			for (int reps = 0; reps < 2; ++reps) {
29	jsr166	1.12	ForkJoinPool g = (procs == 0) ? new ForkJoinPool() :
30	dl	1.1	new ForkJoinPool(procs);
31			lastStealCount = g.getStealCount();
32	dl	1.10	for (int i = 0; i < 20; ++i) {
33	dl	1.1	test(g, num);
34			}
35			System.out.println(g);
36			g.shutdown();
37	dl	1.10	if (!g.awaitTermination(10, TimeUnit.SECONDS))
38			throw new Error();
39			Thread.sleep(1000);
40	dl	1.1	}
41			}
42
43			static void test(ForkJoinPool g, int num) throws Exception {
44			int ps = g.getParallelism();
45			long start = System.currentTimeMillis();
46			DynamicLeftSpineFib f = new DynamicLeftSpineFib(num, null);
47			g.invoke(f);
48			long time = System.currentTimeMillis() - start;
49	dl	1.7	double secs = ((double)time) / 1000.0;
50	dl	1.1	long result = f.getAnswer();
51	dl	1.7	System.out.print("DLSFib " + num + " = " + result);
52	dl	1.1	System.out.printf("\tTime: %7.3f", secs);
53			long sc = g.getStealCount();
54			long ns = sc - lastStealCount;
55			lastStealCount = sc;
56			System.out.printf(" Steals/t: %5d", ns/ps);
57			System.out.printf(" Workers: %8d", g.getPoolSize());
58			System.out.println();
59			}
60
61			// Initialized with argument; replaced with result
62			int number;
63			DynamicLeftSpineFib next;
64
65	jsr166	1.11	DynamicLeftSpineFib(int n, DynamicLeftSpineFib nxt) {
66			number = n; next = nxt;
67	dl	1.1	}
68
69			int getAnswer() {
70			return number;
71			}
72	jsr166	1.11	public void compute() {
73			number = fib(number);
74	dl	1.10	}
75	dl	1.1
76	dl	1.10	static final int fib(int n) {
77			if (n <= 1)
78			return n;
79			int r = 0;
80			DynamicLeftSpineFib rt = null;
81			while (getSurplusQueuedTaskCount() <= 3) {
82			int m = n - 2;
83			n -= 1;
84			if (m <= 1) {
85			r += m;
86			if (n > 1) {
87			r += n - 2;
88			n -= 1;
89	dl	1.7	}
90	dl	1.10	break;
91	dl	1.1	}
92	dl	1.10	(rt = new DynamicLeftSpineFib(m, rt)).fork();
93			}
94			if (n <= 1)
95			r += n;
96			else
97			r += seqFib(n - 2) + fib(n - 1);
98			if (rt != null)
99			r += collectRights(rt);
100			return r;
101			}
102	jsr166	1.11
103	dl	1.10	static final int collectRights(DynamicLeftSpineFib rt) {
104			int r = 0;
105			while (rt != null) {
106			DynamicLeftSpineFib rn = rt.next;
107			rt.next = null;
108			if (rt.tryUnfork())
109			r += fib(rt.number);
110			else {
111			rt.join();
112	dl	1.1	r += rt.number;
113			}
114	dl	1.10	rt = rn;
115	dl	1.1	}
116	dl	1.10	return r;
117	dl	1.1	}
118
119			// Sequential version for arguments less than threshold
120	dl	1.10	static final int seqFib(int n) { // unroll left only
121			int r = 1;
122			do {
123			int m = n - 2;
124			r += m <= 1 ? m : seqFib(m);
125			} while (--n > 1);
126			return r;
127	dl	1.1	}
128	jsr166	1.8
129	dl	1.7	}