test/loops/NoopNoLockLoops.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.concurrent.locks.*;
import java.util.concurrent.atomic.*;
import java.util.*;

public final class NoopNoLockLoops {
    static final ExecutorService pool = Executors.newCachedThreadPool();
    static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
    static boolean print = false;
    static int iters = 20000000;

    public static void main(String[] args) throws Exception {
        int maxThreads = 100;
        if (args.length > 0) 
            maxThreads = Integer.parseInt(args[0]);

        new ReentrantLockLoop(1).test();
        new ReentrantLockLoop(1).test();
        print = true;

        int k = 1;
        for (int i = 1; i <= maxThreads;) {
            System.out.print("Threads: " + i);
            new ReentrantLockLoop(i).test();
            Thread.sleep(100);
            if (i == k) {
                k = i << 1;
                i = i + (i >>> 1);
            } 
            else 
                i = k;
        }
        pool.shutdown();
    }

    static final class ReentrantLockLoop implements Runnable {
        private int v = rng.next();
        private volatile int result = 17;
        private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
        private final CyclicBarrier barrier;
        private final int nthreads;
        private volatile int readBarrier;
        ReentrantLockLoop(int nthreads) {
            this.nthreads = nthreads;
            barrier = new CyclicBarrier(nthreads+1, timer);
        }

        final void test() throws Exception {
            for (int i = 0; i < nthreads; ++i) 
                pool.execute(this);
            barrier.await();
            barrier.await();
            if (print) {
                long time = timer.getTime();
                long tpi = time / ((long)iters * nthreads);
                System.out.print("\t" + LoopHelpers.rightJustify(tpi) + " ns per lock");
                double secs = (double)(time) / 1000000000.0;
                System.out.println("\t " + secs + "s run time");
            }

            int r = result;
            if (r == 0) // avoid overoptimization
                System.out.println("useless result: " + r);
        }

        public final void run() {
            try {
                barrier.await(); 
                int sum = v + 1;
                int x = sum + 1;
                int n = iters;
                while (n-- > 0) {
                    x = LoopHelpers.compute4(x);
                    sum += x;
                    if ((x += readBarrier) == 0)
                        ++readBarrier;

                }
                barrier.await();
                result += sum;
            }
            catch (Exception ie) { 
                return; 
            }
        }
    }

}

Revision:	1.2
Committed:	Mon Feb 19 00:46:06 2007 UTC (17 years, 3 months ago) by dl
Branch:	MAIN
Changes since 1.1:	+2 -6 lines
Log Message:	Uniform headers
#	User	Rev	Content
1	dl	1.1	/*
2			* Written by Doug Lea with assistance from members of JCP JSR-166
3	dl	1.2	* Expert Group and released to the public domain, as explained at
4			* http://creativecommons.org/licenses/publicdomain
5	dl	1.1	*/
6
7			import java.util.concurrent.*;
8			import java.util.concurrent.locks.*;
9			import java.util.concurrent.atomic.*;
10			import java.util.*;
11
12			public final class NoopNoLockLoops {
13			static final ExecutorService pool = Executors.newCachedThreadPool();
14			static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
15			static boolean print = false;
16			static int iters = 20000000;
17
18			public static void main(String[] args) throws Exception {
19			int maxThreads = 100;
20			if (args.length > 0)
21			maxThreads = Integer.parseInt(args[0]);
22
23			new ReentrantLockLoop(1).test();
24			new ReentrantLockLoop(1).test();
25			print = true;
26
27			int k = 1;
28			for (int i = 1; i <= maxThreads;) {
29			System.out.print("Threads: " + i);
30			new ReentrantLockLoop(i).test();
31			Thread.sleep(100);
32			if (i == k) {
33			k = i << 1;
34			i = i + (i >>> 1);
35			}
36			else
37			i = k;
38			}
39			pool.shutdown();
40			}
41
42			static final class ReentrantLockLoop implements Runnable {
43			private int v = rng.next();
44			private volatile int result = 17;
45			private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
46			private final CyclicBarrier barrier;
47			private final int nthreads;
48			private volatile int readBarrier;
49			ReentrantLockLoop(int nthreads) {
50			this.nthreads = nthreads;
51			barrier = new CyclicBarrier(nthreads+1, timer);
52			}
53
54			final void test() throws Exception {
55			for (int i = 0; i < nthreads; ++i)
56			pool.execute(this);
57			barrier.await();
58			barrier.await();
59			if (print) {
60			long time = timer.getTime();
61			long tpi = time / ((long)iters * nthreads);
62			System.out.print("\t" + LoopHelpers.rightJustify(tpi) + " ns per lock");
63			double secs = (double)(time) / 1000000000.0;
64			System.out.println("\t " + secs + "s run time");
65			}
66
67			int r = result;
68			if (r == 0) // avoid overoptimization
69			System.out.println("useless result: " + r);
70			}
71
72			public final void run() {
73			try {
74			barrier.await();
75			int sum = v + 1;
76			int x = sum + 1;
77			int n = iters;
78			while (n-- > 0) {
79			x = LoopHelpers.compute4(x);
80			sum += x;
81			if ((x += readBarrier) == 0)
82			++readBarrier;
83
84			}
85			barrier.await();
86			result += sum;
87			}
88			catch (Exception ie) {
89			return;
90			}
91			}
92			}
93
94			}
95