On Mon, 3 Jul 2023 08:25:06 GMT, Glavo <d...@openjdk.org> wrote:
>> # Benchmark Result
>>
>>
>> sh make/devkit/createJMHBundle.sh
>> bash configure --with-jmh=build/jmh/jars
>> make test TEST="micro:java.lang.StringUpperLower.*"
>>
>>
>>
>> ## 1.
>> [aliyun_ecs_c8i.xlarge](https://help.aliyun.com/document_detail/25378.html#c8i)
>> * cpu : intel xeon sapphire rapids (x64)
>>
>> ``` diff
>> -Benchmark Mode Cnt Score Error Units (baseline)
>> -StringUpperLower.lowerToLower avgt 15 27.180 ± 0.017 ns/op
>> -StringUpperLower.lowerToUpper avgt 15 47.196 ± 0.066 ns/op
>> -StringUpperLower.mixedToLower avgt 15 32.307 ± 0.072 ns/op
>> -StringUpperLower.mixedToUpper avgt 15 44.005 ± 0.414 ns/op
>> -StringUpperLower.upperToLower avgt 15 32.310 ± 0.033 ns/op
>> -StringUpperLower.upperToUpper avgt 15 42.053 ± 0.341 ns/op
>>
>> +Benchmark Mode Cnt Score Error Units
>> +StringUpperLower.lowerToLower avgt 15 16.976 ± 0.043 ns/op (+60.160)
>> +StringUpperLower.lowerToUpper avgt 15 46.373 ± 0.086 ns/op (+1.77%)
>> +StringUpperLower.mixedToLower avgt 15 32.018 ± 0.061 ns/op (+0.9%)
>> +StringUpperLower.mixedToUpper avgt 15 42.019 ± 0.473 ns/op (+4.72%)
>> +StringUpperLower.upperToLower avgt 15 32.052 ± 0.051 ns/op (+0.8%)
>> +StringUpperLower.upperToUpper avgt 15 16.978 ± 0.190 ns/op (+47.69%)
>>
>>
>> ## 2.
>> [aliyun_ecs_c8a.xlarge](https://help.aliyun.com/document_detail/25378.html#c8a)
>> * cpu : amd epc genoa (x64)
>>
>> ``` diff
>> -Benchmark Mode Cnt Score Error Units (baseline)
>> -StringUpperLower.lowerToLower avgt 15 22.164 ± 0.021 ns/op
>> -StringUpperLower.lowerToUpper avgt 15 46.113 ± 0.047 ns/op
>> -StringUpperLower.mixedToLower avgt 15 28.501 ± 0.037 ns/op
>> -StringUpperLower.mixedToUpper avgt 15 38.782 ± 0.038 ns/op
>> -StringUpperLower.upperToLower avgt 15 28.625 ± 0.162 ns/op
>> -StringUpperLower.upperToUpper avgt 15 27.960 ± 0.038 ns/op
>>
>> +Benchmark Mode Cnt Score Error Units
>> +StringUpperLower.lowerToLower avgt 15 15.273 ± 0.012 ns/op (+45.18%)
>> +StringUpperLower.lowerToUpper avgt 15 46.939 ± 0.037 ns/op (-1.75%)
>> +StringUpperLower.mixedToLower avgt 15 27.978 ± 0.015 ns/op (+1.86%)
>> +StringUpperLower.mixedToUpper avgt 15 38.120 ± 0.047 ns/op (+1.73%)
>> +StringUpperLower.upperToLower avgt 15 27.994 ± 0.053 ns/op (+2.25%)
>> +StringUpperLower.upperToUpper avgt 15 17.405 ± 0.006 ns/op (+60.64%)
>>
>>
>>
>> ## 3. [aliyun_ecs_c8y.x...
>
> src/java.base/share/classes/java/lang/StringLatin1.java line 442:
>
>> 440: if (!canEncode(cp)) { // not a latin1
>> character
>> 441: return toLowerCaseEx(str, value, first, locale, false);
>> 442: }
>
> Suggestion:
>
>
>
> I think this branch is unnecessary. All lowercase forms of Latin-1 characters
> can be encoded using Latin-1.
String str0 = new String(new byte[]{-75}, StandardCharsets.ISO_8859_1);
String str1 = str0.toUpperCase();
str0.coder is LATIN1
str1.coder is UTF16
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/14751#discussion_r1250542217
