<i18n dev> RFR: 8345668: ZoneOffset.ofTotalSeconds performance regression [v3]

[Brett Okken]

On Fri, 20 Dec 2024 21:06:16 GMT, Naoto Sato <naoto at 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.
>
> Naoto Sato has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixed compile error

src/java.base/share/classes/java/time/format/DateTimeTextProvider.java line 316:

> 314:             store = createStore(field, locale);
> 315:             CACHE.putIfAbsent(key, store);
> 316:             store = CACHE.get(key);

should this be 
`store = CACHE.computeIfAbsent(key, e -> createStore(e.getKey(), e.getValue()));`

That still allow the optimistic/concurrent get call to succeed most of the time (when already cached) but reduce the interactions with the map when a value is created/set/accessed the first time.

Alternatively, the result of `putIfAbsent` could be checked/used to avoid the second call to `get`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22854#discussion_r1898012555