<i18n dev> RFR: 8335252: ForceInline j.u.Formatter.Conversion#isValid [v2]

[Paul Sandoz]

On Thu, 27 Jun 2024 14:12:36 GMT, Shaojin Wen <duke at openjdk.org> wrote:

>> Currently, the java.util.Formatter$Conversion::isValid method is implemented based on switch, which cannot be inlined because codeSize > 325. This problem can be avoided by implementing it with ImmutableBitSetPredicate.
>> 
>> use `-XX:+UnlockDiagnosticVMOptions -XX:+PrintInlining` to see the master branch:
>> 
>> @ 109   java.util.Formatter$Conversion::isValid (358 bytes)   failed to inline: hot method too big
>> 
>> 
>> current version
>> 
>> @ 109   java.util.Formatter$Conversion::isValid (10 bytes)   inline (hot)
>>   @ 4   jdk.internal.util.ImmutableBitSetPredicate$SmallImmutableBitSetPredicate::test (50 bytes)   inline (hot)
>
> Shaojin Wen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   revert & use `@ForceInline`

Can you provide some additional context here? I think we need to be very careful about the general use @ForceInline in core libraries. While you show a modest performance benefit using a the micro benchmark, will it actually make any difference overall given formatting strings is not particular efficient?

String templates, currently removed, provided good string formatting performance, and the redesign will i think also provide good performance.

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PR Comment: https://git.openjdk.org/jdk/pull/19926#issuecomment-2195095064