On Tue, 14 Oct 2025 23:26:00 GMT, Shaojin Wen <[email protected]> wrote:
> This PR refactors the Double.toHexString method to improve its performance by > eliminating the use of StringBuilder and regex operations. The new > implementation uses a direct byte array approach to construct the hex string > representation, which avoids the overhead of StringBuilder operations and > regex pattern matching. > > Existing tests in `java/lang/Double/ToHexString.java` cover the float > conversions too. The test results run under Mac Book M1 Pro are as follows # before 3f11c4307ee1ca918926c8c522d2fc496947980e -Benchmark Mode Cnt Score Error Units -Doubles.toHexString avgt 15 228.383 ± 17.172 ns/op # after c18f7632f2f2cf0752b3f4651d4cadf95bb859c6 +Benchmark Mode Cnt Score Error Units +Doubles.toHexString avgt 15 15.138 ± 1.070 ns/op More than 10 times performance improvement ------------- PR Comment: https://git.openjdk.org/jdk/pull/27811#issuecomment-3404024458
