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https://issues.apache.org/jira/browse/YARN-6680?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16034125#comment-16034125
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Naganarasimha G R commented on YARN-6680:
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Hi [~daryn],
{{"resulting in a 3X slowdown"}} is based on test results on a non partitioned
cluster or based on a hunch ? if based on test results map be some thing can be
uploaded ?
Agree in the normal flows its unnecessary to use this map but if the labels are
enabled then i feel the locks atleast in few places are required to maintain
consistency.
for ex. {{RMNodeLabelsManager.getResourceByLabel()}} though query is done for
nolabel read lock is required as intermittently node's partition mapping could
be changed, or node can be deactivated etc... all the ops where write lock is
held ?
> Avoid locking overhead for NO_LABEL lookups
> -------------------------------------------
>
> Key: YARN-6680
> URL: https://issues.apache.org/jira/browse/YARN-6680
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: resourcemanager
> Affects Versions: 2.8.0
> Reporter: Daryn Sharp
> Assignee: Daryn Sharp
> Attachments: YARN-6680.patch
>
>
> Labels are managed via a hash that is protected with a read lock. The lock
> acquire and release are each just as expensive as the hash lookup itself -
> resulting in a 3X slowdown.
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