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Hudson commented on HADOOP-9956: -------------------------------- SUCCESS: Integrated in Hadoop-Yarn-trunk #391 (See [https://builds.apache.org/job/Hadoop-Yarn-trunk/391/]) Move HADOOP-9956 to correct release in CHANGES.txt (daryn: http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1541740) * /hadoop/common/trunk/hadoop-common-project/hadoop-common/CHANGES.txt HADOOP-9956. RPC listener inefficiently assigns connections to readers (daryn) (daryn: http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1541736) * /hadoop/common/trunk/hadoop-common-project/hadoop-common/CHANGES.txt * /hadoop/common/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/CommonConfigurationKeys.java * /hadoop/common/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Server.java * /hadoop/common/trunk/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/ipc/TestIPC.java > 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 > Fix For: 3.0.0, 2.3.0, 0.23.10 > > Attachments: HADOOP-9956.branch-23.patch, HADOOP-9956.patch, > 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 was sent by Atlassian JIRA (v6.1#6144)