dev@grizzly.java.net

Re: closed connection under high load

From: Oleksiy Stashok <oleksiy.stashok_at_oracle.com>
Date: Thu, 06 Mar 2014 17:39:22 -0800

On 06.03.14 01:29, Mkrtchyan, Tigran wrote:
>
> ----- Original Message -----
>> From: "Oleksiy Stashok" <oleksiy.stashok_at_oracle.com>
>> To: dev_at_grizzly.java.net
>> Sent: Thursday, March 6, 2014 2:35:00 AM
>> Subject: Re: closed connection under high load
>>
>> Hi Tigran,
>>
>>>> Hi Tigran,
>>>>
>>>> looks like the connection is getting closed because of IOException or -1
>>>> returned during channel.read(), which is expected.
>>>> So IMO it's nothing decided by Grizzly, it's either other side or local
>>>> OS closed the connection.
>>> Yes, in did, the client closes the connection. But it looks like the reason
>>> of it
>>> that reply from server sent 15sec after request is arrived. The filter
>>> itself took
>>> max 800ms. Any ideas how to trace where rest of the time was spent?
>> You can register ConnectionProbe for each Connection:
>> / connection.getMonitoringConfig().addProbes(new
>> ConnectionProbe() {
>> .....
>> });/
>>
>> and monitor different Connection events and time when it happened.
>> It might be interesting to monitor onWriteEvent() and see if write delay
>> occurs on Grizzly/Java or OS level. For example Grizzly reports the
>> socketChannel.write(ByteBuffer) had been accepted the ByteBuffer, but
>> the peer didn't get this data, which means the delay happens in OS layer.
> I was logging in my code where I start to process the request and this
> was with quite a delay. Unfortunately, my work load nodes are turned
> off till the end of the week as we update cooling infrastructure in our
> data center. But I will continue investigations next week. Is there any
> best practice in which relations should be the number of selector and
> worker threads?
By default we'd suggest selector-threads-count=CPU-count and
worker-threads-count=CPU-count*2
I'd also recommend to use SameThreadStrategy (no worker threads), where
it's possible. For example if the app logic doesn't have any blocking,
waiting kind of code - there is no reason to pay for a thread context
switch.

>
> BTW, what do you think about proposed change:
> https://github.com/GrizzlyNIO/grizzly-mirror/pull/1
Looks good.
Will apply it.

Thank you!

WBR,
Alexey.


>
> Tigran.
>
>> Thanks.
>>
>> WBR,
>> Alexey.
>>
>>> Looking at the requests log I can see that request processing is not
>>> equally distributed.
>>> Some connections processed quite active, while others are not. Is there a
>>> way how I can see
>>> selector threads activity?
>>>
>>> Tigran.
>>>
>>>> Thanks.
>>>>
>>>> WBR,
>>>> Alexey.
>>>>
>>>> On 26.02.14 14:06, Mkrtchyan, Tigran wrote:
>>>>> Hi,
>>>>>
>>>>> we observe that grizzly decides to close connection under high load.
>>>>> Any idea how to find the reason?
>>>>>
>>>>> Thanks,
>>>>> Tigran.
>>>>>
>>>>> java.io.IOException: Connection closed
>>>>> at
>>>>> org.glassfish.grizzly.asyncqueue.TaskQueue.onClose(TaskQueue.java:302)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.AbstractNIOAsyncQueueWriter.onClose(AbstractNIOAsyncQueueWriter.java:591)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.transport.TCPNIOTransport.closeConnection(TCPNIOTransport.java:389)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at org.glassfish.grizzly.nio.NIOConnection$2.run(NIOConnection.java:439)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.DefaultSelectorHandler$RunnableTask.run(DefaultSelectorHandler.java:489)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.DefaultSelectorHandler.processPendingTaskQueue(DefaultSelectorHandler.java:295)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.DefaultSelectorHandler.processPendingTasks(DefaultSelectorHandler.java:286)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.DefaultSelectorHandler.preSelect(DefaultSelectorHandler.java:100)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.SelectorRunner.doSelect(SelectorRunner.java:326)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at org.glassfish.grizzly.nio.SelectorRunner.run(SelectorRunner.java:271)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at java.lang.Thread.run(Thread.java:744) [na:1.7.0_51]
>>>>> Caused by: java.lang.Exception: Close stack trace
>>>>> at
>>>>> org.glassfish.grizzly.nio.NIOConnection.close0(NIOConnection.java:426)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.transport.TCPNIOConnection.close0(TCPNIOConnection.java:292)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.transport.TCPNIOTransport.read(TCPNIOTransport.java:648)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.transport.TCPNIOTransportFilter.handleRead(TCPNIOTransportFilter.java:75)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.filterchain.TransportFilter.handleRead(TransportFilter.java:173)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:546)
>>>>> [grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>>>> at
>>>>> org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
>>>>> ~[grizzly-framework-2.3.5.jar:2.3.5]
>>