On Wed, 15 Mar 2023 11:26:21 GMT, Eirik Bjorsnos <d...@openjdk.org> wrote:
> By avoiding a bit shift operation for the latin1 fast-path test, we can speed > up the `java.lang.CharacterData.of` method by ~25% for latin1 code points. > > The latin1 test is currently implemented as `ch >>> 8 == 0`. We can replace > this with `ch >= 0 && ch <= 0xFF` for a noticable performance gain > (especially for Latin1 code points): > > This method is called frequently by various property-determining methods in > `java.lang.Character` like `isLowerCase`, `isDigit` etc, so one should expect > improvements for all these methods. > > Performance is tested using the `Characters.isDigit` benchmark using the > digits '0' (decimal 48, in CharacterDataLatin1) and '\u0660' (decimal 1632, > in CharacterData00): > > Baseline: > > > Benchmark (codePoint) Mode Cnt Score Error Units > Characters.isDigit 48 avgt 15 0.870 ± 0.011 ns/op > Characters.isDigit 1632 avgt 15 2.168 ± 0.017 ns/op > > PR: > > > Benchmark (codePoint) Mode Cnt Score Error Units > Characters.isDigit 48 avgt 15 0.654 ± 0.007 ns/op > Characters.isDigit 1632 avgt 15 2.032 ± 0.019 ns/op Marked as reviewed by stsypanov (Author). ------------- PR: https://git.openjdk.org/jdk/pull/13040
