1 /*
   2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  */
  22 
  23 /*
  24  * This file is available under and governed by the GNU General Public
  25  * License version 2 only, as published by the Free Software Foundation.
  26  * However, the following notice accompanied the original version of this
  27  * file:
  28  *
  29  * Written by Doug Lea with assistance from members of JCP JSR-166
  30  * Expert Group and released to the public domain, as explained at
  31  * http://creativecommons.org/publicdomain/zero/1.0/
  32  */
  33 
  34 /*
  35  * @test
  36  * @bug 4486658
  37  * @summary Checks for responsiveness of futures to cancellation.
  38  * Runs under the assumption that ITERS computations require more than
  39  * TIMEOUT msecs to complete.
  40  * @library /lib/testlibrary/
  41  * @run main/timeout=2000 CancelledFutureLoops
  42  */
  43 
  44 import static java.util.concurrent.TimeUnit.MILLISECONDS;
  45 
  46 import java.util.SplittableRandom;
  47 import java.util.concurrent.BrokenBarrierException;
  48 import java.util.concurrent.Callable;
  49 import java.util.concurrent.CyclicBarrier;
  50 import java.util.concurrent.ExecutionException;
  51 import java.util.concurrent.ExecutorService;
  52 import java.util.concurrent.Executors;
  53 import java.util.concurrent.Future;
  54 import java.util.concurrent.locks.ReentrantLock;
  55 import jdk.testlibrary.Utils;
  56 
  57 public final class CancelledFutureLoops {
  58     static final long LONG_DELAY_MS = Utils.adjustTimeout(10_000);
  59     static final ExecutorService pool = Executors.newCachedThreadPool();
  60     static final SplittableRandom rnd = new SplittableRandom();
  61     static boolean print = false;
  62     static final int ITERS = 1000000;
  63     static final long TIMEOUT = 100;
  64 
  65     public static void main(String[] args) throws Exception {
  66         int maxThreads = 5;
  67         if (args.length > 0)
  68             maxThreads = Integer.parseInt(args[0]);
  69 
  70         print = true;
  71 
  72         for (int i = 2; i <= maxThreads; i += (i+1) >>> 1) {
  73             System.out.print("Threads: " + i);
  74             try {
  75                 new FutureLoop(i, rnd.split()).test();
  76             }
  77             catch (BrokenBarrierException bb) {
  78                 // OK; ignore
  79             }
  80             catch (ExecutionException ee) {
  81                 // OK; ignore
  82             }
  83             Thread.sleep(TIMEOUT);
  84         }
  85         pool.shutdown();
  86         if (! pool.awaitTermination(6 * LONG_DELAY_MS, MILLISECONDS))
  87             throw new Error();
  88     }
  89 
  90     static final class FutureLoop implements Callable {
  91         private final int nthreads;
  92         private final SplittableRandom rnd;
  93         private final ReentrantLock lock = new ReentrantLock();
  94         private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
  95         private final CyclicBarrier barrier;
  96         private int v;
  97         FutureLoop(int nthreads, SplittableRandom rnd) {
  98             this.nthreads = nthreads;
  99             this.rnd = rnd;
 100             barrier = new CyclicBarrier(nthreads+1, timer);
 101             v = rnd.nextInt();
 102         }
 103 
 104         final void test() throws Exception {
 105             Future[] futures = new Future[nthreads];
 106             for (int i = 0; i < nthreads; ++i)
 107                 futures[i] = pool.submit(this);
 108 
 109             barrier.await();
 110             Thread.sleep(TIMEOUT);
 111             boolean tooLate = false;
 112             for (int i = 1; i < nthreads; ++i) {
 113                 if (!futures[i].cancel(true))
 114                     tooLate = true;
 115                 // Unbunch some of the cancels
 116                 if ( (i & 3) == 0)
 117                     Thread.sleep(1 + rnd.nextInt(5));
 118             }
 119 
 120             Object f0 = futures[0].get();
 121             if (!tooLate) {
 122                 for (int i = 1; i < nthreads; ++i) {
 123                     if (!futures[i].isDone() || !futures[i].isCancelled())
 124                         throw new Error("Only one thread should complete");
 125                 }
 126             }
 127             else
 128                 System.out.print("(cancelled too late) ");
 129 
 130             long endTime = System.nanoTime();
 131             long time = endTime - timer.startTime;
 132             if (print) {
 133                 double secs = (double)(time) / 1000000000.0;
 134                 System.out.println("\t " + secs + "s run time");
 135             }
 136 
 137         }
 138 
 139         public final Object call() throws Exception {
 140             barrier.await();
 141             int sum = v;
 142             int x = 0;
 143             int n = ITERS;
 144             while (n-- > 0) {
 145                 lock.lockInterruptibly();
 146                 try {
 147                     v = x = LoopHelpers.compute1(v);
 148                 }
 149                 finally {
 150                     lock.unlock();
 151                 }
 152                 sum += LoopHelpers.compute2(LoopHelpers.compute2(x));
 153             }
 154             return new Integer(sum);
 155         }
 156     }
 157 
 158 }