On Fri, 20 Dec 2024 19:55:06 GMT, Naoto Sato <na...@openjdk.org> wrote:
> The change made in [JDK-8288723](https://bugs.openjdk.org/browse/JDK-8288723) > seems innocuous, but it caused this performance regression. Partially > reverting the change (ones that involve `computeIfAbsent()`) to the original. > Provided a benchmark that iterates the call to `ZoneOffset.ofTotalSeconds(0)` > 1,000 times, which improves the operation time from 3,946ns to 2,241ns. src/java.base/share/classes/java/time/ZoneOffset.java line 432: > 430: result = new ZoneOffset(totalSeconds); > 431: SECONDS_CACHE.putIfAbsent(totalSecs, result); > 432: result = SECONDS_CACHE.get(totalSecs); putIfAbsent() returns the existing value (if any), the 2nd get can be avoided by using the non-null value if returned or returning the result just created. Suggestion: var existing = SECONDS_CACHE.putIfAbsent(totalSecs, result); return (existing != null) ? existing : result; It should perform better than doing the `get` again. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/22854#discussion_r1894362437
