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Eric Payne commented on MAPREDUCE-6473: --------------------------------------- bq. In the above scenario when thread 2 comes along and finds that the provider list is null , since thread 1 is already in the synchronized block, thread 2 will wait [~kshukla], Yes, you are correct. I had missed that. Thanks for the clarification. +1 (non-binding) > Job submission can take a long time during Cluster initialization > ----------------------------------------------------------------- > > Key: MAPREDUCE-6473 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-6473 > Project: Hadoop Map/Reduce > Issue Type: Improvement > Components: performance > Reporter: Kuhu Shukla > Assignee: Kuhu Shukla > Attachments: 99%ile.png, MAPREDUCE-6473-PerfTest.txt, > MAPREDUCE-6473-v1.patch, MAPREDUCE-6473-v2.patch, MAPREDUCE-6473-v3.patch, > MAPREDUCE-6473-v4.patch, MAPREDUCE-6473-v5.patch, MAPREDUCE-6473-v6.patch, > MAPREDUCE-6473-v7.patch, avgtime.png > > > During initialization in Cluster.java, the framework provider classes are > loaded inside a sync block which can considerably increase job submission > time when the number of submissions are high. The motive is to reduce time > spent in this sync block safely to improve performance. > {noformat} > synchronized (frameworkLoader) { > for (ClientProtocolProvider provider : frameworkLoader) { > LOG.debug("Trying ClientProtocolProvider : " > + provider.getClass().getName()); > {noformat} -- This message was sent by Atlassian JIRA (v6.3.4#6332)