On Tue, 31 Jan 2023 15:57:43 GMT, Per Minborg <pminb...@openjdk.org> wrote:
> `ZoneOffset` instances are cached by the `ZoneOffset` class itself for values > in the range [-18h, 18h] for each second that is on an even quarter of an > hour (i.e. at most 2*18*4+1 = 145 values). > > Instead of using a `ConcurrentHashMap` for caching instanced, we could > instead use an `AtomicReferenceArray` with direct slot value access for said > even seconds. This will improve performance and reduce the number of object > even though the backing array will go from an initial 32 in the CHM to an > initial/final 145 in the ARA. The CHM will contain much more objects and > array slots for typical numbers of entries in the cache and will compute > hash/bucket/collision on the hot code path for each cache access. src/java.base/share/classes/java/time/ZoneOffset.java line 147: > 145: > 146: /** Cache of time-zone offset by offset in seconds [-18h, +18h] for > each even quarter of an hour. */ > 147: private static final AtomicReferenceArray<ZoneOffset> SECONDS_CACHE > = new AtomicReferenceArray<>(MAX_SECONDS_CACHE_SLOT * 2 + 1); Can we use regular array instead? ------------- PR: https://git.openjdk.org/jdk/pull/12346
