test/loops/LeftSpineFib.java

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

public final class LeftSpineFib extends RecursiveAction {

    // Performance-tuning constant:
    static int sequentialThreshold;
    static long lastStealCount;

    public static void main(String[] args) throws Exception {
        int procs = 0;
        int num = 45;
        sequentialThreshold = 2;
        try {
            if (args.length > 0)
                procs = Integer.parseInt(args[0]);
            if (args.length > 1)
                num = Integer.parseInt(args[1]);
            if (args.length > 2)
                sequentialThreshold = Integer.parseInt(args[2]);
        }
        catch (Exception e) {
            System.out.println("Usage: java LeftSpineFib <threads> <number> [<sequntialThreshold>]");
            return;
        }


        for (int reps = 0; reps < 2; ++reps) {
            ForkJoinPool g = (procs == 0) ? new ForkJoinPool() :
                new ForkJoinPool(procs);
            //            g.setMaintainsParallelism(false);
            lastStealCount = g.getStealCount();
            for (int i = 0; i < 20; ++i) {
                test(g, num);
                Thread.sleep(50);
            }
            System.out.println(g);
            g.shutdown();
            if (!g.awaitTermination(8, TimeUnit.SECONDS)) {
                System.out.println(g);
                throw new Error();
            }
            g = null;
            //            System.gc();
            Thread.sleep(500);
        }
    }

    static void test(ForkJoinPool g, int num) throws Exception {
        int ps = g.getParallelism();
        long start = System.currentTimeMillis();
        LeftSpineFib f = new LeftSpineFib(num, null);
        g.invoke(f);
        long time = System.currentTimeMillis() - start;
        double secs = ((double)time) / 1000.0;
        long result = f.getAnswer();
        System.out.print("JLSFib " + 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.getRunningThreadCount());
        System.out.printf(" Workers: %8d", g.getPoolSize());
        System.out.println();
    }


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

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

    int getAnswer() {
        return number;
    }

    public final void compute() {
        int n = number;
        if (n > 1) {
            LeftSpineFib rt = null;
            int r = 0;
            while (n > sequentialThreshold) {
                int m = n - 2;
                if (m <= 1)
                    r += m;
                else
                    (rt = new LeftSpineFib(m, rt)).fork();
                n -= 1;
            }
            r += n <= 1 ? n : seqFib(n);
            if (rt != null)
                r += collectRights(rt);
            number = r;
        }
    }

    static final int collectRights(LeftSpineFib rt) {
        int r = 0;
        while (rt != null) {
            LeftSpineFib rn = rt.next;
            rt.next = null;
            if (rt.tryUnfork()) rt.compute(); else rt.join();
            //            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:	1.4
Committed:	Wed Jul 4 20:07:02 2012 UTC (11 years, 10 months ago) by jsr166
Branch:	MAIN
Changes since 1.3:	+0 -2 lines
Log Message:	trailing newlines
#	User	Rev	Content
1	dl	1.1	import java.util.*;
2			import java.util.concurrent.*;
3
4			public final class LeftSpineFib extends RecursiveAction {
5
6			// Performance-tuning constant:
7			static int sequentialThreshold;
8			static long lastStealCount;
9	jsr166	1.2
10	dl	1.1	public static void main(String[] args) throws Exception {
11			int procs = 0;
12			int num = 45;
13			sequentialThreshold = 2;
14			try {
15			if (args.length > 0)
16			procs = Integer.parseInt(args[0]);
17			if (args.length > 1)
18			num = Integer.parseInt(args[1]);
19	jsr166	1.2	if (args.length > 2)
20	dl	1.1	sequentialThreshold = Integer.parseInt(args[2]);
21			}
22			catch (Exception e) {
23			System.out.println("Usage: java LeftSpineFib <threads> <number> [<sequntialThreshold>]");
24			return;
25			}
26
27	jsr166	1.2
28	dl	1.1	for (int reps = 0; reps < 2; ++reps) {
29	jsr166	1.3	ForkJoinPool g = (procs == 0) ? new ForkJoinPool() :
30	dl	1.1	new ForkJoinPool(procs);
31			// g.setMaintainsParallelism(false);
32			lastStealCount = g.getStealCount();
33			for (int i = 0; i < 20; ++i) {
34			test(g, num);
35			Thread.sleep(50);
36			}
37			System.out.println(g);
38			g.shutdown();
39			if (!g.awaitTermination(8, TimeUnit.SECONDS)) {
40			System.out.println(g);
41			throw new Error();
42			}
43			g = null;
44			// System.gc();
45			Thread.sleep(500);
46			}
47			}
48
49			static void test(ForkJoinPool g, int num) throws Exception {
50			int ps = g.getParallelism();
51			long start = System.currentTimeMillis();
52			LeftSpineFib f = new LeftSpineFib(num, null);
53			g.invoke(f);
54			long time = System.currentTimeMillis() - start;
55			double secs = ((double)time) / 1000.0;
56			long result = f.getAnswer();
57			System.out.print("JLSFib " + num + " = " + result);
58			System.out.printf("\tTime: %7.3f", secs);
59			long sc = g.getStealCount();
60			long ns = sc - lastStealCount;
61			lastStealCount = sc;
62			System.out.printf(" Steals/t: %5d", ns/ps);
63			// System.out.printf(" Workers: %8d", g.getRunningThreadCount());
64			System.out.printf(" Workers: %8d", g.getPoolSize());
65			System.out.println();
66			}
67
68
69			// Initialized with argument; replaced with result
70			int number;
71			LeftSpineFib next;
72
73			LeftSpineFib(int n, LeftSpineFib nxt) { number = n; next = nxt; }
74
75			int getAnswer() {
76			return number;
77			}
78
79			public final void compute() {
80			int n = number;
81			if (n > 1) {
82			LeftSpineFib rt = null;
83			int r = 0;
84			while (n > sequentialThreshold) {
85			int m = n - 2;
86			if (m <= 1)
87			r += m;
88			else
89			(rt = new LeftSpineFib(m, rt)).fork();
90			n -= 1;
91			}
92			r += n <= 1 ? n : seqFib(n);
93			if (rt != null)
94			r += collectRights(rt);
95			number = r;
96			}
97			}
98
99			static final int collectRights(LeftSpineFib rt) {
100			int r = 0;
101			while (rt != null) {
102			LeftSpineFib rn = rt.next;
103			rt.next = null;
104			if (rt.tryUnfork()) rt.compute(); else rt.join();
105			// rt.join();
106			r += rt.number;
107			rt = rn;
108			}
109			return r;
110			}
111
112			// Sequential version for arguments less than threshold
113			static final int seqFib(int n) { // unroll left only
114			int r = 1;
115			do {
116			int m = n - 2;
117			r += m <= 1 ? m : seqFib(m);
118			} while (--n > 1);
119			return r;
120			}
121
122			}