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.concurrent.*;
import java.util.*;
import java.util.concurrent.TimeUnit;
//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:	1.14
Committed:	Sat Feb 16 21:37:44 2013 UTC (11 years, 3 months ago) by jsr166
Branch:	MAIN
Changes since 1.13:	+6 -0 lines
Log Message:	add missing public domain notices
#	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	dl	1.10	import java.util.concurrent.*;
8	dl	1.1	import java.util.*;
9	dl	1.10	import java.util.concurrent.TimeUnit;
10			//import java.util.concurrent.*;
11	dl	1.1
12			public final class DynamicLeftSpineFib extends RecursiveAction {
13
14			static long lastStealCount;
15	jsr166	1.11
16	dl	1.1	public static void main(String[] args) throws Exception {
17			int procs = 0;
18	dl	1.10	int num = 45;
19	dl	1.1	try {
20			if (args.length > 0)
21			procs = Integer.parseInt(args[0]);
22			if (args.length > 1)
23			num = Integer.parseInt(args[1]);
24			}
25			catch (Exception e) {
26	dl	1.7	System.out.println("Usage: java DynamicLeftSpineFib <threads> <number> [<sequntialThreshold>]");
27	dl	1.1	return;
28			}
29
30	jsr166	1.11
31	dl	1.1	for (int reps = 0; reps < 2; ++reps) {
32	jsr166	1.12	ForkJoinPool g = (procs == 0) ? new ForkJoinPool() :
33	dl	1.1	new ForkJoinPool(procs);
34			lastStealCount = g.getStealCount();
35	dl	1.10	for (int i = 0; i < 20; ++i) {
36	dl	1.1	test(g, num);
37			}
38			System.out.println(g);
39			g.shutdown();
40	dl	1.10	if (!g.awaitTermination(10, TimeUnit.SECONDS))
41			throw new Error();
42			Thread.sleep(1000);
43	dl	1.1	}
44			}
45
46			static void test(ForkJoinPool g, int num) throws Exception {
47			int ps = g.getParallelism();
48			long start = System.currentTimeMillis();
49			DynamicLeftSpineFib f = new DynamicLeftSpineFib(num, null);
50			g.invoke(f);
51			long time = System.currentTimeMillis() - start;
52	dl	1.7	double secs = ((double)time) / 1000.0;
53	dl	1.1	long result = f.getAnswer();
54	dl	1.7	System.out.print("DLSFib " + num + " = " + result);
55	dl	1.1	System.out.printf("\tTime: %7.3f", secs);
56			long sc = g.getStealCount();
57			long ns = sc - lastStealCount;
58			lastStealCount = sc;
59			System.out.printf(" Steals/t: %5d", ns/ps);
60			System.out.printf(" Workers: %8d", g.getPoolSize());
61			System.out.println();
62			}
63
64
65			// Initialized with argument; replaced with result
66			int number;
67			DynamicLeftSpineFib next;
68
69	jsr166	1.11	DynamicLeftSpineFib(int n, DynamicLeftSpineFib nxt) {
70			number = n; next = nxt;
71	dl	1.1	}
72
73			int getAnswer() {
74			return number;
75			}
76	jsr166	1.11	public void compute() {
77			number = fib(number);
78	dl	1.10	}
79	dl	1.1
80	dl	1.10	static final int fib(int n) {
81			if (n <= 1)
82			return n;
83			int r = 0;
84			DynamicLeftSpineFib rt = null;
85			while (getSurplusQueuedTaskCount() <= 3) {
86			int m = n - 2;
87			n -= 1;
88			if (m <= 1) {
89			r += m;
90			if (n > 1) {
91			r += n - 2;
92			n -= 1;
93	dl	1.7	}
94	dl	1.10	break;
95	dl	1.1	}
96	dl	1.10	(rt = new DynamicLeftSpineFib(m, rt)).fork();
97			}
98			if (n <= 1)
99			r += n;
100			else
101			r += seqFib(n - 2) + fib(n - 1);
102			if (rt != null)
103			r += collectRights(rt);
104			return r;
105			}
106	jsr166	1.11
107	dl	1.10	static final int collectRights(DynamicLeftSpineFib rt) {
108			int r = 0;
109			while (rt != null) {
110			DynamicLeftSpineFib rn = rt.next;
111			rt.next = null;
112			if (rt.tryUnfork())
113			r += fib(rt.number);
114			else {
115			rt.join();
116	dl	1.1	r += rt.number;
117			}
118	dl	1.10	rt = rn;
119	dl	1.1	}
120	dl	1.10	return r;
121	dl	1.1	}
122
123			// Sequential version for arguments less than threshold
124	dl	1.10	static final int seqFib(int n) { // unroll left only
125			int r = 1;
126			do {
127			int m = n - 2;
128			r += m <= 1 ? m : seqFib(m);
129			} while (--n > 1);
130			return r;
131	dl	1.1	}
132	jsr166	1.8
133	dl	1.7	}