[ https://issues.apache.org/jira/browse/HDFS-12533?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Erik Krogen reassigned HDFS-12533: ---------------------------------- Assignee: (was: Erik Krogen) > NNThroughputBenchmark threads get stuck on UGI.getCurrentUser() > --------------------------------------------------------------- > > Key: HDFS-12533 > URL: https://issues.apache.org/jira/browse/HDFS-12533 > Project: Hadoop HDFS > Issue Type: Improvement > Reporter: Erik Krogen > Priority: Major > > In {{NameNode#getRemoteUser()}}, it first attempts to fetch from the RPC user > (not a synchronized operation), and if there is no RPC call, it will call > {{UserGroupInformation#getCurrentUser()}} (which is {{synchronized}}). This > makes it efficient for RPC operations (the bulk) so that there is not too > much contention. > In NNThroughputBenchmark, however, there is no RPC call since we bypass that > later, so with a high thread count many of the threads are getting stuck. At > one point I attached a profiler and found that quite a few threads had been > waiting for {{#getCurrentUser()}} for 2 minutes ( ! ). When taking this away > I found some improvement in the throughput numbers I was seeing. To more > closely emulate a real NN we should improve this issue. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org