[
https://issues.apache.org/jira/browse/DIRMINA-678?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13212541#comment-13212541
]
Laxman commented on DIRMINA-678:
--------------------------------
My apologies for initiating discussion on very old issue.
We encountered this issue in Hadoop (HDFS and Mapeduce) as well.
Finally, I was redirected to this patch. After going through the patch, I feel
there is a problem.
{code}
+ if ((((channel instanceof DatagramChannel) &&
((DatagramChannel) channel)
+ .isConnected()))
+ || ((channel instanceof SocketChannel) &&
((SocketChannel) channel)
+ .isConnected())) {
+ // The channel is not connected anymore. Cancel
+ // the associated key then.
+ key.cancel();
+
+ // Set the flag to true to avoid a selector switch
+ brokenSession = true;
+ }
{code}
IMO, the comments and code are conflicting here.
Comments says "channel is not connected" and code checks whether "channel is
connected".
Am I reading something wrong here?
> NioProcessor 100% CPU usage on Linux (epoll selector bug)
> ---------------------------------------------------------
>
> Key: DIRMINA-678
> URL: https://issues.apache.org/jira/browse/DIRMINA-678
> Project: MINA
> Issue Type: Bug
> Components: Core
> Affects Versions: 2.0.0-M4
> Environment: CentOS 5.x, 32/64-bit, 32/64-bit Sun JDK 1.6.0_12, also
> _11/_10/_09 and Sun JDK 1.7.0 b50, Kernel 2.6.18-92.1.22.el5 and also older
> versions,
> Reporter: Serge Baranov
> Fix For: 2.0.3
>
> Attachments: mina-2.0.3.diff, snap973.png, snap974.png
>
>
> It's the same bug as described at http://jira.codehaus.org/browse/JETTY-937 ,
> but affecting MINA in the very similar way.
> NioProcessor threads start to eat 100% resources per CPU. After 10-30 minutes
> of running depending on the load (sometimes after several hours) one of the
> NioProcessor starts to consume all the available CPU resources probably
> spinning in the epoll select loop. Later, more threads can be affected by the
> same issue, thus 100% loading all the available CPU cores.
> Sample trace:
> NioProcessor-10 [RUNNABLE] CPU time: 5:15
> sun.nio.ch.EPollArrayWrapper.epollWait(long, int, long, int)
> sun.nio.ch.EPollArrayWrapper.poll(long)
> sun.nio.ch.EPollSelectorImpl.doSelect(long)
> sun.nio.ch.SelectorImpl.lockAndDoSelect(long)
> sun.nio.ch.SelectorImpl.select(long)
> org.apache.mina.transport.socket.nio.NioProcessor.select(long)
> org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run()
> org.apache.mina.util.NamePreservingRunnable.run()
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor$Worker)
> java.util.concurrent.ThreadPoolExecutor$Worker.run()
> java.lang.Thread.run()
> It seems to affect any NIO based Java server applications running in the
> specified environment.
> Some projects provide workarounds for similar JDK bugs, probably MINA can
> also think about a workaround.
> As far as I know, there are at least 3 users who experience this issue with
> Jetty and all of them are running CentOS (some distribution default setting
> is a trigger?). As for MINA, I'm not aware of similar reports yet.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
