[
https://issues.apache.org/jira/browse/HADOOP-9956?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13766253#comment-13766253
]
Binglin Chang commented on HADOOP-9956:
---------------------------------------
bq. the listener will wait for sockets to close or idle out before accepting
more.
New connection request should have higher priority than idle connections, it
could be better to close them actively rather than wait for sockets to idle out.
> RPC listener inefficiently assigns connections to readers
> ---------------------------------------------------------
>
> Key: HADOOP-9956
> URL: https://issues.apache.org/jira/browse/HADOOP-9956
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: ipc
> Affects Versions: 2.0.0-alpha, 3.0.0
> Reporter: Daryn Sharp
> Assignee: Daryn Sharp
> Attachments: HADOOP-9956.patch
>
>
> The socket listener and readers use a complex synchronization to update the
> reader's NIO {{Selector}}. Updating active selectors is not thread-safe so
> precautions are required.
> However, the current locking choreography results in a serialized
> distribution of new connections to the parallel socket readers. A
> slower/busier reader can stall the listener and throttle performance.
> The problem manifests as unexpectedly low cpu utilization by the listener and
> readers (~20-30%) under heavy load. The call queue is shallow when it should
> be overflowing.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
