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Date: Thu, 17 Jul 2014 17:39:06 +0000 (UTC)
From: "Tsuyoshi OZAWA (JIRA)" <jira@apache.org>
To: yarn-issues@hadoop.apache.org
Message-ID: <JIRA.12727993.1405618502662.63774.1405618746230@arcas>
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Subject: [jira] [Updated] (YARN-2313) Livelock can occur on FairScheduler
 when there are lots entry in queue
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     [ https://issues.apache.org/jira/browse/YARN-2313?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Tsuyoshi OZAWA updated YARN-2313:
---------------------------------

    Attachment: YARN-2313.1.patch

Ideally, UPDATE_INTERVAL should be calculated based on current number of entries in queue. Another workaround is making UPDATE_INTERVAL configurable. Attached patch takes the latter approach, because it's easy to implement.

> Livelock can occur on FairScheduler when there are lots entry in queue
> ----------------------------------------------------------------------
>
>                 Key: YARN-2313
>                 URL: https://issues.apache.org/jira/browse/YARN-2313
>             Project: Hadoop YARN
>          Issue Type: Bug
>          Components: fairscheduler
>    Affects Versions: 2.4.1
>            Reporter: Tsuyoshi OZAWA
>            Assignee: Tsuyoshi OZAWA
>         Attachments: YARN-2313.1.patch
>
>
> Observed livelock on FairScheduler when there are lots entry in queue. After my investigating code, following case can occur:
> 1. {{update()}} called by UpdateThread takes longer times than UPDATE_INTERVAL(500ms) if there are lots queue.
> 2. UpdateThread goes busy loop.
> 3. Other threads(AllocationFileReloader, ResourceManager$SchedulerEventDispatcher) can wait forever.


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