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https://issues.apache.org/jira/browse/YARN-3453?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Karthik Kambatla updated YARN-3453:
-----------------------------------
Summary: Fair Scheduler: Parts of preemption logic uses
DefaultResourceCalculator even in DRF mode causing thrashing (was: Fair
Scheduler : Parts of preemption logic uses DefaultResourceCalculator even in
DRF mode causing thrashing)
> Fair Scheduler: Parts of preemption logic uses DefaultResourceCalculator even
> in DRF mode causing thrashing
> -----------------------------------------------------------------------------------------------------------
>
> Key: YARN-3453
> URL: https://issues.apache.org/jira/browse/YARN-3453
> Project: Hadoop YARN
> Issue Type: Bug
> Components: fairscheduler
> Affects Versions: 2.6.0
> Reporter: Ashwin Shankar
> Assignee: Arun Suresh
> Attachments: YARN-3453.1.patch, YARN-3453.2.patch, YARN-3453.3.patch,
> YARN-3453.4.patch, YARN-3453.5.patch
>
>
> There are two places in preemption code flow where DefaultResourceCalculator
> is used, even in DRF mode.
> Which basically results in more resources getting preempted than needed, and
> those extra preempted containers aren’t even getting to the “starved” queue
> since scheduling logic is based on DRF's Calculator.
> Following are the two places :
> 1. {code:title=FSLeafQueue.java|borderStyle=solid}
> private boolean isStarved(Resource share)
> {code}
> A queue shouldn’t be marked as “starved” if the dominant resource usage
> is >= fair/minshare.
> 2. {code:title=FairScheduler.java|borderStyle=solid}
> protected Resource resToPreempt(FSLeafQueue sched, long curTime)
> {code}
> --------------------------------------------------------------
> One more thing that I believe needs to change in DRF mode is : during a
> preemption round,if preempting a few containers results in satisfying needs
> of a resource type, then we should exit that preemption round, since the
> containers that we just preempted should bring the dominant resource usage to
> min/fair share.
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