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Weiwei Yang commented on HDFS-12163: ------------------------------------ Run 1 DN in mini ozone cluster, there were *402* threads once the cluster is up, checked the thread dump, there are *280* RPC handler threads, with following trace {code} IPC Server handler 0 on 51641@2330 - priority:5 - threadId:0x45 - nativeId:NA - state:WAITING stackTrace: java.lang.Thread.State: WAITING at sun.misc.Unsafe.park(Unsafe.java:-1) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078) at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467) at org.apache.hadoop.ipc.CallQueueManager.take(CallQueueManager.java:287) at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2661) {code} this is because {{dfs.storage.service.handler.count}} = {{10}} {{ozone.ksm.handler.count.key}} = {{200}} we are setting a pretty big value for KSM handlers, this is not necessary for a mini cluster, we can overwrite this config in mini cluster to reduce the number of threads. I will check the leak issue a bit later. > Ozone: MiniOzoneCluster uses 400+ threads > ----------------------------------------- > > Key: HDFS-12163 > URL: https://issues.apache.org/jira/browse/HDFS-12163 > Project: Hadoop HDFS > Issue Type: Sub-task > Components: ozone, test > Reporter: Tsz Wo Nicholas Sze > Assignee: Weiwei Yang > Attachments: TestOzoneThreadCount20170719.patch > > > Checked the number of active threads used in MiniOzoneCluster with various > settings: > - Local handlers > - Distributed handlers > - Ratis-Netty > - Ratis-gRPC > The results are similar for all the settings. It uses 400+ threads for an > 1-datanode MiniOzoneCluster. > Moreover, there is a thread leak -- a number of the threads do not shutdown > after the test is finished. Therefore, when tests run consecutively, the > later tests use more threads. > Will post the details in comments. -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org