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Bug ID: JDK-6500685 VM hangs after 'made not entrant java.util.concurrent.........'
JDK-6500685 : VM hangs after 'made not entrant java.util.concurrent.........'

Details
Type:
Bug
Submit Date:
2006-12-05
Status:
Resolved
Updated Date:
2010-04-02
Project Name:
JDK
Resolved Date:
2006-12-15
Component:
hotspot
OS:
solaris
Sub-Component:
compiler
CPU:
x86
Priority:
P2
Resolution:
Fixed
Affected Versions:
7
Fixed Versions:
hs10 (b05)

Related Reports
Backport:
Backport:

Sub Tasks

Description
This test case (ShortCancelledProducerConsumerLoops.java) is an abbreviated
version of
   j2se/test/java/util/concurrent/BlockingQueue/CancelledProducerConsumerLoops.java
with fewer iterations.

It passes OK using C2 version "20061012073853.nips.bug6480445" but
hangs when using C2 version "20061012181105.jrose.dolphin-cleanups"

Passes OK when run with '-client'

/*
 * @test 1.4 06/04/21
 * @bug 4486658
 * @compile -source 1.5 ShortCancelledProducerConsumerLoops.java
 * @run main/othervm ShortCancelledProducerConsumerLoops
 * @summary Checks for responsiveness of blocking queues to cancellation.
 * Runs under the assumption that ITERS computations require more than
 * TIMEOUT msecs to complete.
 */
/*
 * 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 java.util.concurrent.*;

public class ShortCancelledProducerConsumerLoops {
    static final int CAPACITY =      100;
    static final long TIMEOUT = 100;

    static final ExecutorService pool = Executors.newCachedThreadPool();
    static boolean print = false;

    public static void main(String[] args) throws Exception {
        int maxPairs = 8;
        int iters = 550000;

        if (args.length > 0)
            maxPairs = Integer.parseInt(args[0]);

        print = true;

        for (int i = 1; i <= maxPairs; i += (i+1) >>> 1) {
            System.out.println("Pairs:" + i);
            try {
                oneTest(i, iters);
            }
            catch (BrokenBarrierException bb) {
                // OK, ignore
            }
            Thread.sleep(100);
        }
        pool.shutdown();
   }

    static void oneRun(BlockingQueue<Integer> q, int npairs, int iters) throws Exception {
        LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
        CyclicBarrier barrier = new CyclicBarrier(npairs * 2 + 1, timer);
        Future[] prods = new Future[npairs];
        Future[] cons = new Future[npairs];

        for (int i = 0; i < npairs; ++i) {
            prods[i] = pool.submit(new Producer(q, barrier, iters));
            cons[i] = pool.submit(new Consumer(q, barrier, iters));
        }
        barrier.await();
        Thread.sleep(TIMEOUT);
        boolean tooLate = false;

        for (int i = 1; i < npairs; ++i) {
            if (!prods[i].cancel(true))
                tooLate = true;
            if (!cons[i].cancel(true))
                tooLate = true;
        }

        Object p0 = prods[0].get();
        Object c0 = cons[0].get();

        if (!tooLate) {
            for (int i = 1; i < npairs; ++i) {
                if (!prods[i].isDone() || !prods[i].isCancelled())
                    throw new Error("Only one producer thread should complete");
                if (!cons[i].isDone() || !cons[i].isCancelled())
                    throw new Error("Only one consumer thread should complete");
            }
        }
        else
            System.out.print("(cancelled too late) ");

        long endTime = System.nanoTime();
        long time = endTime - timer.startTime;
        if (print) {
            double secs = (double)(time) / 1000000000.0;
            System.out.println("\t " + secs + "s run time");
        }
    }

    static void oneTest(int pairs, int iters) throws Exception {

        if (print)
            System.out.print("ArrayBlockingQueue      ");
        oneRun(new ArrayBlockingQueue<Integer>(CAPACITY), pairs, iters);

        if (print)
            System.out.print("LinkedBlockingQueue     ");
        oneRun(new LinkedBlockingQueue<Integer>(CAPACITY), pairs, iters);

        if (print)
            System.out.print("SynchronousQueue        ");
        oneRun(new SynchronousQueue<Integer>(), pairs, iters / 8);

        /* PriorityBlockingQueue is unbounded
        if (print)
            System.out.print("PriorityBlockingQueue   ");
        oneRun(new PriorityBlockingQueue<Integer>(iters / 2 * pairs), pairs, iters / 4);
        */
    }

    static abstract class Stage implements Callable<Integer> {
        final BlockingQueue<Integer> queue;
        final CyclicBarrier barrier;
        final int iters;
        Stage (BlockingQueue<Integer> q, CyclicBarrier b, int iters) {
            queue = q;
            barrier = b;
            this.iters = iters;
        }
    }

    static class Producer extends Stage {
        Producer(BlockingQueue<Integer> q, CyclicBarrier b, int iters) {
            super(q, b, iters);
        }

        public Integer call() throws Exception {
            barrier.await();
            int s = 0;
            int l = 4321;
            for (int i = 0; i < iters; ++i) {
                l = LoopHelpers.compute1(l);
                s += LoopHelpers.compute2(l);
                if (!queue.offer(new Integer(l), 1, TimeUnit.SECONDS))
                    break;
            }
            return new Integer(s);
        }
    }

    static class Consumer extends Stage {
        Consumer(BlockingQueue<Integer> q, CyclicBarrier b, int iters) {
            super(q, b, iters);
        }

        public Integer call() throws Exception {
            barrier.await();
            int l = 0;
            int s = 0;
            for (int i = 0; i < iters; ++i) {
                Integer x = queue.poll(1, TimeUnit.SECONDS);
                if (x == null)
                    break;
                l = LoopHelpers.compute1(x.intValue());
                s += l;
            }
            return new Integer(s);
        }
    }
}
Runtime output is as follows:


% /usr/bin/time java -server -showversion -XX:+PrintCompilation -Xbatch ShortCancelledProducerConsumerLoops
java version "1.7.0-ea"
Java(TM) SE Runtime Environment (build 1.7.0-ea-b03)
Java HotSpot(TM) Server VM (build 20061012181105.jrose.dolphin-cleanups, mixed mode)

Pairs:1
ArrayBlockingQueue      ---   n   java.lang.Thread::currentThread (static)
---   n   java.lang.Thread::currentThread (static)
  1   b   LoopHelpers::compute2 (28 bytes)
  2   b   java.util.concurrent.locks.ReentrantLock$Sync::nonfairTryAcquire (67 bytes)
  3   b   java.util.concurrent.locks.ReentrantLock$NonfairSync::tryAcquire (6 bytes)
  4   b   java.util.concurrent.locks.AbstractOwnableSynchronizer::setExclusiveOwnerThread (6 bytes)
  5   b   java.lang.Object::<init> (1 bytes)
---   n   java.lang.Thread::isInterrupted
  6   b   java.lang.Thread::interrupted (8 bytes)
  7   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::release (33 bytes)
  8   b   java.util.concurrent.locks.ReentrantLock$Sync::tryRelease (45 bytes)
  9   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::setState (6 bytes)
 10   b   java.util.concurrent.locks.AbstractQueuedSynchronizer$Node::predecessor (19 bytes)
 11   b   java.util.concurrent.locks.ReentrantLock::unlock (10 bytes)
 12   b   java.util.concurrent.TimeUnit$4::toNanos (11 bytes)
 13   b   java.util.concurrent.TimeUnit::x (27 bytes)
 14   b   java.util.concurrent.locks.ReentrantLock$Sync::isHeldExclusively (16 bytes)
 15   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::acquireInterruptibly (28 bytes)
 16   b   LoopHelpers::compute1 (72 bytes)
 17   b   java.util.concurrent.ArrayBlockingQueue::inc (18 bytes)
 18   b   java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject::signal (33 bytes)
 19   b   java.util.concurrent.locks.ReentrantLock::lockInterruptibly (9 bytes)
 15   made not entrant  java.util.concurrent.locks.AbstractQueuedSynchronizer::acquireInterruptibly (28 bytes)
---   n   sun.misc.Unsafe::compareAndSwapInt
---   n   sun.misc.Unsafe::compareAndSwapObject
 20   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::setHead (16 bytes)
 21   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::compareAndSetTail (13 bytes)
 22   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::addWaiter (50 bytes)
 23   b   java.util.concurrent.locks.AbstractQueuedSynchronizer$Node::<init> (15 bytes)
 24  !b   java.util.concurrent.ArrayBlockingQueue::poll (101 bytes)
 25  !b   java.util.concurrent.ArrayBlockingQueue::offer (117 bytes)
 26   b   java.lang.Number::<init> (5 bytes)
 27   b   java.lang.Integer::<init> (10 bytes)
  1%  b   ShortCancelledProducerConsumerLoops$Producer::call @ 16 (78 bytes)
  2%  b   ShortCancelledProducerConsumerLoops$Consumer::call @ 14 (76 bytes)
---   n   sun.misc.Unsafe::unpark
---   n   sun.misc.Unsafe::park
 28   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::compareAndSetWaitStatus (13 bytes)
---   n   java.lang.System::nanoTime (static)
---   n   sun.misc.Unsafe::putObject
 29   b   java.util.concurrent.locks.LockSupport::setBlocker (12 bytes)
 30   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::isOnSyncQueue (33 bytes)
 31   b   java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject::awaitNanos (160 bytes)
 32   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::enq (69 bytes)
 33   b   java.util.concurrent.locks.AbstractQueuedSynchronizer::transferForSignal (45 bytes)
 34   b   java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject::doSignal (43 bytes)
 31   made not entrant  java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject::awaitNanos (160 bytes)

xxxxxxx - hangs here xxxxxxxx

                                    

Comments
EVALUATION

A line of experimental code stowed away in a putback for 6470497.
It broke some memory dependency edges between volatile field refs and mem barriers.
                                     
2006-12-09
SUGGESTED FIX

A tiny fix:
http://analemma.sfbay.sun.com/net/prt-archiver.sfbay/data/archived_workspaces/main/c2_baseline/2006/20061208230422.jrose.6500685/workspace/webrevs/webrev-2006.12.09/index.html
*** (#1 of 1): [ UNSAVED ] ###@###.###
                                     
2006-12-09



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