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https://issues.apache.org/jira/browse/HADOOP-15811?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16636316#comment-16636316
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Steven Rand commented on HADOOP-15811:
--------------------------------------

Worth noting, the intrinsic methods mentioned above are on by default starting 
in 8u152 ([https://bugs.openjdk.java.net/browse/JDK-8154945,] 
[https://www.oracle.com/technetwork/java/javase/8u152-relnotes-3850503.html).]  

> Optimizations for Java's TLS performance
> ----------------------------------------
>
>                 Key: HADOOP-15811
>                 URL: https://issues.apache.org/jira/browse/HADOOP-15811
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: common
>    Affects Versions: 1.0.0
>            Reporter: Daryn Sharp
>            Priority: Major
>
> Java defaults to using /dev/random and disables intrinsic methods used in hot 
> code paths.  Both cause highly synchronized impls to be used that 
> significantly degrade performance.
> * -Djava.security.egd=file:/dev/urandom
> * -XX:+UseMontgomerySquareIntrinsic
> * -XX:+UseMontgomeryMultiplyIntrinsic
> * -XX:+UseSquareToLenIntrinsic
> * -XX:+UseMultiplyToLenIntrinsic
> These settings significantly boost KMS server performance.  Under load, 
> threads are not jammed in the SSLEngine.



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