On Mon, 1 Nov 2021 13:04:20 GMT, Claes Redestad <redes...@openjdk.org> wrote:
> Prompted by a request from Volkan Yazıcı I took a look at why the java.time > formatters are less efficient for some common patterns than custom formatters > in apache-commons and log4j. This patch reduces the gap, without having > looked at the third party implementations. > > When printing times: > - Avoid turning integral values into `String`s before appending them to the > buffer > - Specialize `appendFraction` for `NANO_OF_SECOND` to avoid use of > `BigDecimal` > > This means a speed-up and reduction in allocations when formatting almost any > date or time pattern, and especially so when including sub-second parts > (`S-SSSSSSSSS`). > > Much of the remaining overhead can be traced to the need to create a > `DateTimePrintContext` and adjusting `Instant`s into a `ZonedDateTime` > internally. We could likely also win performance by specializing some common > patterns. > > Testing: tier1-3 This pull request has now been integrated. Changeset: ce8c7670 Author: Claes Redestad <redes...@openjdk.org> URL: https://git.openjdk.java.net/jdk/commit/ce8c76700ba854f43c48d32b068b30e7d78d9d1e Stats: 564 lines in 4 files changed: 533 ins; 12 del; 19 mod 8276220: Reduce excessive allocations in DateTimeFormatter Reviewed-by: scolebourne, naoto ------------- PR: https://git.openjdk.java.net/jdk/pull/6188
