[jira] [Created] (HDFS-10662) Optimize UTF8 string/byte conversions

["Daryn Sharp (JIRA)" <ji...@apache.org>]

Daryn Sharp created HDFS-10662:
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             Summary: 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


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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