On Sat, 5 Apr 2025 05:30:25 GMT, Shaojin Wen <s...@openjdk.org> wrote:
>> Improve the performance of UUID::toString by using Long.expand and SWAR >> (SIMD within a register) instead of table lookup. Eliminating the table >> lookup can also avoid the performance degradation problem when the cache >> misses. > > Shaojin Wen has updated the pull request incrementally with one additional > commit since the last revision: > > simplify code Please update the performance comparisons (percentage improvement.) src/java.base/share/classes/java/util/UUID.java line 491: > 489: * hexadecimal representation, concatenate these hexadecimal strings > into one continuous string, and then interpret > 490: * this string as a hexadecimal number to form and return a long > value. > 491: */ Is there a reference describing this technique? Such as the Hacker's Delight citation used in java.lang.Long? If not a longer descriptive comment would be good for maintainability. ------------- PR Review: https://git.openjdk.org/jdk/pull/22928#pullrequestreview-2851674685 PR Review Comment: https://git.openjdk.org/jdk/pull/22928#discussion_r2096283194
