Thread Blocking? sun.misc.Unsafe.park(Native Method)

[jason zhao yang]

Hi,

Previously, when we are doing loading testing staging server, we found "sun.misc.Unsafe.park(Native Method)" error from Datastax Driver. 

But we were unable to reproduce it on local.

Now when I try benchmark using Java MicroBenchMark Harness. The thread problem was able to reproduce.

I am using single node local Cassandra 2.1.1, Java Driver 2.1.5, Ubuntu 14.04LTS.

Here is the testing code, simply async and then getUninterruptibly.

(About JMH, please see this: About JMH)

    @Benchmark 

    public void test() throws InterruptedException {

    ResultSetFuture future = session.executeAsync(QUERY);

        future.getUninterruptibly()

    }

    public static void main(String[] args) throws RunnerException {

        Options opt = new OptionsBuilder()

                .include(MyBenchmark.class.getSimpleName())

                .forks(1)

                .build();

        new Runner(opt).run();

    }

 

Here is the errror log:

Thread[New I/O worker #2,5,main]

  at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)

  at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)

  at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:79)

  at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)

  at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)

  at org.jboss.netty.channel.socket.nio.SelectorUtil.select(SelectorUtil.java:68)

  at org.jboss.netty.channel.socket.nio.AbstractNioSelector.select(AbstractNioSelector.java:415)

  at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:212)

  at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:89)

  at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)

  at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)

  at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)

  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

  at java.lang.Thread.run(Thread.java:745)

Thread[Hashed wheel timer #1,5,main]

  at java.lang.Thread.sleep(Native Method)

  at org.jboss.netty.util.HashedWheelTimer$Worker.waitForNextTick(HashedWheelTimer.java:483)

  at org.jboss.netty.util.HashedWheelTimer$Worker.run(HashedWheelTimer.java:392)

  at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)

  at java.lang.Thread.run(Thread.java:745)

Thread[Hashed wheel timer #2,5,main]

  at java.lang.Thread.sleep(Native Method)

  at org.jboss.netty.util.HashedWheelTimer$Worker.waitForNextTick(HashedWheelTimer.java:483)

  at org.jboss.netty.util.HashedWheelTimer$Worker.run(HashedWheelTimer.java:392)

  at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)

  at java.lang.Thread.run(Thread.java:745)

Thread[Reaper-0,5,main]

  at sun.misc.Unsafe.park(Native Method)

  at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)

  at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)

  at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)

  at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)

  at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067)

  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)

  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

  at java.lang.Thread.run(Thread.java:745)

Thank you very much.

Zhao Yang

[Olivier Michallat]

Hi,

That thread is not blocked, it's sitting idle in an executor that has nothing to do

How are you closing the Cluster instance at the end of your test?

--

Olivier Michallat

Driver & tools engineer, DataStax

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[jason zhao yang]

Hi Olivier,

Thanks for your reply.

I didn't close the connection. I initialize Session as static.

And the exception happened in the middle of the benchmark.

So you mean the following log is not a problem?

Thread[Reaper-0,5,main]

 at sun.misc.Unsafe.park(Native Method)

 at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)

 at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)

 at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)

 at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)

 at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067)

 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)

 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

 at java.lang.Thread.run(Thread.java:745)

Zhao Yang

在 2015年10月12日星期一 UTC+8下午9:08:57，Olivier Michallat写道：