RFR: JDK-8310502 : Optimization for j.l.Long.fastUUID() [v34]

[Roger Riggs]

On Thu, 29 Jun 2023 13:26:18 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 two additional commits since the last revision:
> 
>  - fix comments typo
>  - Update full name

Changes requested by rriggs (Reviewer).

src/java.base/share/classes/java/util/HexDigits.java line 108:

> 106:      * Combine two hex shorts into one int based on big endian
> 107:      */
> 108:     static int digit(int b0, int b1) {

The method name `digit` is not very informative.
As it is package private it should be more descriptive and describe the parameters and result.
Perhaps `packDigits` or `encodeAndPackHexDigits`.

-------------

PR Review: https://git.openjdk.org/jdk/pull/14578#pullrequestreview-1505333183
PR Review Comment: https://git.openjdk.org/jdk/pull/14578#discussion_r1246644155