RFR: 8310502 : optimization for UUID#toString [v3]

[温绍锦]

On Wed, 21 Jun 2023 11:06:08 GMT, 温绍锦 <duke at openjdk.org> wrote:

>> By optimizing the implementation of java.lang.Long#fastUUID, the performance of the java.util.UUID#toString method can be significantly improved.
>> 
>> The following are the test results of JMH: 
>> 
>> Benchmark                     Mode  Cnt      Score      Error   Units
>> UUIDUtilsBenchmark.new       thrpt    5  92676.550 ±  292.213  ops/ms
>> UUIDUtilsBenchmark.original  thrpt    5  37040.165 ± 1023.532  ops/ms
>
> 温绍锦 has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8310502 : hex literal

* benchmark code
https://github.com/wenshao/jdk_8310502_test/blob/main/src/main/java/com/alibaba/openjdk/UUIDUtilsBenchmark.java

* benchmark result

Benchmark                 Mode  Cnt     Score    Error   Units
HexUtilsBenchmark.fast   thrpt    5  2971.864 ± 17.277  ops/ms
HexUtilsBenchmark.jdk    thrpt    5  1984.653 ± 11.733  ops/ms

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PR Comment: https://git.openjdk.org/jdk/pull/14578#issuecomment-1600843797