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https://issues.apache.org/jira/browse/TEZ-1074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13976030#comment-13976030
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Bikas Saha commented on TEZ-1074:
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I thought you had some proposal around sending counters that have changed
instead of all counters. Also do you think we could leverage PB instead of
Writable for this and get some benefits. e.g. use PERFORMANCE flags in PB?
> DAGAppMaster takes lots of CPU when running a reasonably large job in the
> cluster
> ---------------------------------------------------------------------------------
>
> Key: TEZ-1074
> URL: https://issues.apache.org/jira/browse/TEZ-1074
> Project: Apache Tez
> Issue Type: Bug
> Reporter: Rajesh Balamohan
> Attachments: Screen Shot 2014-04-19 at 7.26.36 PM.png,
> TEZ-1074-v2.patch
>
>
> - Ran a job which used 200 containers.
> - DAGAppMaster was running at 70% CPU most of the time during the job.
> - Profiling revealed that lots of time was spent on TezEvent.readFields -->
> ... --> TaskStatusUpdateEvent.readFields().
> - Default "tez.task.am.heartbeat.interval-ms.max=100" ms. With 200
> containers, potentially 2000 events (these events have TezCounters) per
> second would be processed by DAGAppMaster.
> With large job, cpu usage of DAGAppMaster can bloat up significantly.
> One option to reduce CPU usage could be to send modified TezCounters in
> TezStatusUpdateEvent.
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