<i18n dev> RFR: 8302871: Speed up StringLatin1.regionMatchesCI [v4]

[Eirik Bjorsnos]

On Mon, 20 Feb 2023 16:23:32 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> Is it not already in CharacterDataLatin1?
>> 
>> Here is a comparison of relying on improvements in `CharacterDataLatin1.toUpperCase/toLowerCase` only vs. using `CharacterDataLatin1.equalsIgnoreCase`:
>> 
>> Character.toUpperCase/toLowerCase only:
>> 
>> 
>> Benchmark                                  (codePoints)  (size)  Mode  Cnt     Score    Error  Units
>> RegionMatchesIC.Latin1.regionMatchesIC      ascii-match    1024  avgt   15  1310.582 ± 84.777  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC   ascii-mismatch    1024  avgt   15     4.547 ±  0.545  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC     number-match    1024  avgt   15   686.947 ± 11.850  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC  number-mismatch    1024  avgt   15     3.836 ±  0.634  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC       lat1-match    1024  avgt   15  2107.219 ± 17.662  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC    lat1-mismatch    1024  avgt   15     4.924 ±  0.829  ns/op
>> 
>> 
>> CharacterDataLatin1.equalsIgnoreCase:
>> 
>> 
>> Benchmark                                  (codePoints)  (size)  Mode  Cnt     Score    Error  Units
>> RegionMatchesIC.Latin1.regionMatchesIC      ascii-match    1024  avgt   15   742.467 ± 34.490  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC   ascii-mismatch    1024  avgt   15     3.960 ±  0.046  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC     number-match    1024  avgt   15   361.158 ± 37.096  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC  number-mismatch    1024  avgt   15     4.039 ±  0.521  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC       lat1-match    1024  avgt   15  1158.091 ± 41.617  ns/op
>> RegionMatchesIC.Latin1.regionMatchesIC    lat1-mismatch    1024  avgt   15     4.358 ±  0.123  ns/op
>
> Oops, I lost context and thought this was in `StringLatin1`.
> 
> Thanks for running the numbers with #12623. Looks like you're getting big enough of an improvement on top.

Yes, seems `equalsIgnoreCase` carries its weight.

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PR: https://git.openjdk.org/jdk/pull/12632