hadoop-yarn-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Sandy Ryza (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (YARN-1909) FairScheduler isStartvedForFairShare does not work when fairShare == 1
Date Mon, 07 Apr 2014 22:46:19 GMT

    [ https://issues.apache.org/jira/browse/YARN-1909?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13962349#comment-13962349
] 

Sandy Ryza commented on YARN-1909:
----------------------------------

This looks like an MR1 issue, so moving it to MAPREDUCE.

> FairScheduler isStartvedForFairShare does not work when fairShare == 1
> ----------------------------------------------------------------------
>
>                 Key: YARN-1909
>                 URL: https://issues.apache.org/jira/browse/YARN-1909
>             Project: Hadoop YARN
>          Issue Type: Bug
>            Reporter: Anubhav Dhoot
>            Assignee: Anubhav Dhoot
>
> If the fair share returned by the scheduler getFairShare() == 1 the pool will never be
marked as being starved because of the following calculation:
> {code}
> boolean isStarvedForFairShare(PoolSchedulable sched) { 
>   int desiredFairShare = (int) Math.floor(Math.min( sched.getFairShare() / 2, sched.getDemand()));

>   return (sched.getRunningTasks() < desiredFairShare); 
> }
> {code}
> getFairShare() returns 1
> Math.min calculation will return 0.5
> Math.Floor() which will cause the desiredFairShare to be set to 0.
> the return value to be 'false' (0 < 0)
> If you have a small job without a minimum set it will not get scheduled if a large job
is hogging the slots.



--
This message was sent by Atlassian JIRA
(v6.2#6252)

Mime
View raw message