[jira] Updated: (MAPREDUCE-2118) optimize getJobSetupAndCleanupTasks

["Joydeep Sen Sarma (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/MAPREDUCE-2118?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Joydeep Sen Sarma updated MAPREDUCE-2118:
-----------------------------------------

    Attachment: mapreduce.2118.2.patch

Refreshed patch against latest trunk. I didn't remove the comment because it's actually in a block of comment containing notes on why the call was removed. i think it's better to leave these comments in because the change is subtle but very important.

> optimize getJobSetupAndCleanupTasks 
> ------------------------------------
>
>                 Key: MAPREDUCE-2118
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-2118
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>            Reporter: Joydeep Sen Sarma
>            Assignee: Joydeep Sen Sarma
>         Attachments: mapreduce-2118.1.patch, mapreduce.2118.2.patch
>
>
> in every heartbeat, while holding the JobTracker global lock, all jobs are scanned for job setup/cleanup, task setup/cleanup. on a large system with many trackers (and heartbeats) and many jobs - this becomes the bottleneck for JT throughput.
> One possible route may be to rework the code to not require the JT lock while asking the JIP whether it has a setup/cleanup task. 

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