simplemutexloops.java

来自「SRI international 发布的OAA框架软件」· Java 代码 · 共 109 行

/*
 * @test
 * @synopsis multiple threads using a single lock
 */
/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain. Use, modify, and
 * redistribute this code in any way without acknowledgement.
 */

import edu.emory.mathcs.backport.java.util.concurrent.*;
import edu.emory.mathcs.backport.java.util.concurrent.locks.*;
import java.util.*;

public final class SimpleMutexLoops {
    static final ExecutorService pool = Executors.newCachedThreadPool();
    static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
    static boolean print = false;
    static int iters = 10000000;

    public static void main(String[] args) throws Exception {
//        int maxThreads = 100;
//        if (args.length > 0)
//            maxThreads = Integer.parseInt(args[0]);
//
//        new MutexLoop(1).test();
//        new MutexLoop(1).test();
//        print = true;
//
//        int k = 1;
//        for (int i = 1; i <= maxThreads;) {
//            System.out.print("Threads: " + i);
//            new MutexLoop(i).test();
//            Thread.sleep(100);
//            if (i == k) {
//                k = i << 1;
//                i = i + (i >>> 1);
//            }
//            else
//                i = k;
//        }
//        pool.shutdown();
    }

//    static final class MutexLoop implements Runnable {
//        private int v = rng.next();
//        private volatile int result = 17;
//        private final Mutex lock = new Mutex();
//        private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
//        private final CyclicBarrier barrier;
//        private final int nthreads;
//        private volatile int readBarrier;
//        MutexLoop(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() {
//            final Mutex lock = this.lock;
//            try {
//                barrier.await();
//                int sum = v + 1;
//                int x = 0;
//                int n = iters;
//                while (n-- > 0) {
//                    lock.lock();
//                    int k = (sum & 3);
//                    if (k > 0) {
//                        x = v;
//                        while (k-- > 0)
//                            x = LoopHelpers.compute1(x);
//                        v = x;
//                    }
//                    else x = sum + 1;
//                    lock.unlock();
//                    if ((x += readBarrier) == 0)
//                        ++readBarrier;
//                    for (int l = x & 7; l > 0; --l)
//                        sum += LoopHelpers.compute1(sum);
//                }
//                barrier.await();
//                result += sum;
//            }
//            catch (Exception ie) {
//                return;
//            }
//        }
//    }

}