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From "Sunil G (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (YARN-6788) Improve performance of resource profile branch
Date Wed, 02 Aug 2017 18:19:00 GMT

     [ https://issues.apache.org/jira/browse/YARN-6788?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Sunil G updated YARN-6788:
--------------------------
    Attachment: YARN-6788-YARN-3926.021.patch

Updating a new patch addressing the concern regarding DCL.

By Quoting below links
# http://www.cs.umd.edu/~pugh/java/memoryModel/jsr-133-faq.html#synchronization
# https://www.securecoding.cert.org/confluence/display/java/LCK10-J.+Use+a+correct+form+of+the+double-checked+locking+idiom
# http://docs.oracle.com/javase/specs/jls/se7/html/jls-17.html#jls-17.5

DCL is safer as per this design pattern (Volatile model). So quoting 1) and 2), we can convert
all major variables which are written under synchronized block could be changed to volatile.
This will cover the open loop holes which you mentioned. 3) explains the JMM for final variable
which writes and flushes once thread exits block.

Based on these observations, i think its fine to change to volatile for now. We can open a
ticket and discuss regarding other linear approaches, however as per this jira title, this
does not affect performance (variable initializes only one when RM is started). So if its
fine, we can go with this approach.
[~templedf] and [~leftnoteasy]

> Improve performance of resource profile branch
> ----------------------------------------------
>
>                 Key: YARN-6788
>                 URL: https://issues.apache.org/jira/browse/YARN-6788
>             Project: Hadoop YARN
>          Issue Type: Sub-task
>          Components: nodemanager, resourcemanager
>            Reporter: Sunil G
>            Assignee: Sunil G
>            Priority: Blocker
>         Attachments: YARN-6788-YARN-3926.001.patch, YARN-6788-YARN-3926.002.patch, YARN-6788-YARN-3926.003.patch,
YARN-6788-YARN-3926.004.patch, YARN-6788-YARN-3926.005.patch, YARN-6788-YARN-3926.006.patch,
YARN-6788-YARN-3926.007.patch, YARN-6788-YARN-3926.008.patch, YARN-6788-YARN-3926.009.patch,
YARN-6788-YARN-3926.010.patch, YARN-6788-YARN-3926.011.patch, YARN-6788-YARN-3926.012.patch,
YARN-6788-YARN-3926.013.patch, YARN-6788-YARN-3926.014.patch, YARN-6788-YARN-3926.015.patch,
YARN-6788-YARN-3926.016.patch, YARN-6788-YARN-3926.017.patch, YARN-6788-YARN-3926.018.patch,
YARN-6788-YARN-3926.019.patch, YARN-6788-YARN-3926.020.patch, YARN-6788-YARN-3926.021.patch
>
>
> Currently we could see a 15% performance delta with this branch. 
> Few performance improvements to improve the same.
> Also this patch will handle [comments|https://issues.apache.org/jira/browse/YARN-6761?focusedCommentId=16075418&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16075418]
from [~leftnoteasy].



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