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From "Zhe Zhang (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HDFS-10662) Optimize UTF8 string/byte conversions
Date Thu, 01 Sep 2016 00:03:22 GMT

     [ https://issues.apache.org/jira/browse/HDFS-10662?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Zhe Zhang updated HDFS-10662:
-----------------------------
    Status: Patch Available  (was: Reopened)

> Optimize UTF8 string/byte conversions
> -------------------------------------
>
>                 Key: HDFS-10662
>                 URL: https://issues.apache.org/jira/browse/HDFS-10662
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: hdfs
>            Reporter: Daryn Sharp
>            Assignee: Daryn Sharp
>             Fix For: 2.8.0, 3.0.0-alpha1
>
>         Attachments: HDFS-10662-branch-2.7.00.patch, HDFS-10662.patch, HDFS-10662.patch.1
>
>
> String/byte conversions may take either a Charset instance or its canonical name.  One
might think a Charset instance would be faster due to avoiding a lookup and instantiation
of a Charset, but it's not.  The canonical string name variants will cache the string encoder/decoder
(obtained from a Charset) resulting in better performance.
> LOG4J2-935 describes a real-world performance boost.  I micro-benched a marginal runtime
improvement on jdk 7/8.  However for a 16 byte path, using the canonical name generated 50%
less garbage.  For a 64 byte path, 25% of the garbage.  Given the sheer number of times that
paths are (re)parsed, the cost adds up quickly.



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