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Eric Payne commented on YARN-7149: ---------------------------------- I believe that this is related to the refactoring done to the way User Limit is calculated in trunk / branch-2. I cannot reproduce the above use case prior to YARN-5889. I think the reason is because prior to YARN-5889 (and in 2.8), the result of {{LeafQueue#computUserLimit}} was always greater than the amount used by any given user. After YARN-5889, the return value of {{UsersManager#computeUserLimit}} can be equal to the amount used by any given user. Then, in {{LeafQueue#getTotalPendingResourcesConsideringUserLimit}}, we can have a situation where {{userLimit}} - {{user.getUsed}} always equals 0, even when it shouldn't. > Cross-queue preemption sometimes starves an underserved queue > ------------------------------------------------------------- > > Key: YARN-7149 > URL: https://issues.apache.org/jira/browse/YARN-7149 > Project: Hadoop YARN > Issue Type: Bug > Components: capacity scheduler > Affects Versions: 2.9.0, 3.0.0-alpha3 > Reporter: Eric Payne > Assignee: Eric Payne > > In branch 2 and trunk, I am consistently seeing some use cases where > cross-queue preemption does not happen when it should. I do not see this in > branch-2.8. > Use Case: > | | *Size* | *Minimum Container Size* | > |MyCluster | 20 GB | 0.5 GB | > | *Queue Name* | *Capacity* | *Absolute Capacity* | *Minimum User Limit > Percent (MULP)* | *User Limit Factor (ULF)* | > |Q1 | 50% = 10 GB | 100% = 20 GB | 10% = 1 GB | 2.0 | > |Q2 | 50% = 10 GB | 100% = 20 GB | 10% = 1 GB | 2.0 | > - {{User1}} launches {{App1}} in {{Q1}} and consumes all resources (20 GB) > - {{User2}} launches {{App2}} in {{Q2}} and requests 10 GB > - _Note: containers are 0.5 GB._ > - Preemption monitor kills 2 containers (equals 1 GB) from {{App1}} in {{Q1}}. > - Capacity Scheduler assigns 2 containers (equals 1 GB) to {{App2}} in {{Q2}}. > - _No more containers are ever preempted, even though {{Q2}} is far > underserved_ -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: yarn-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: yarn-issues-h...@hadoop.apache.org