RFR: 8372348: Adjust some UL / JFR string deduplication output messages

[Matthias Baesken]

On Sat, 22 Nov 2025 11:33:47 GMT, Francesco Andreuzzi <fandreuzzi at openjdk.org> wrote:

>> There is some UL output in the string deduplication code that is not very clear and has room for improvement.
>> The inspected strings number should be shown and the new unknown strings get a changed text.
>> (also the new JFR strip dedup event  description is slightly adjusted)
>
> src/hotspot/share/gc/shared/stringdedup/stringDedupStat.cpp line 218:
> 
>> 216:   log_debug(stringdedup)("      Known:       %12zu(%5.1f%%)", _known, known_percent);
>> 217:   log_debug(stringdedup)("      Shared:      %12zu(%5.1f%%)", _known_shared, known_shared_percent);
>> 218:   log_debug(stringdedup)("      New unknown: %12zu(%5.1f%%)" STRDEDUP_BYTES_FORMAT,
> 
> I'm wondering if just `Unknown` would be more self-explanatory than `New unknown`? We have `Known` already, and `New unknown` is the complement of `Known`

Maybe , but the variables are named `_new / _new_bytes` and the JFR fields also have 'new' in the name. So it maybe makes sense to keep 'new' in the UL and related output.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28455#discussion_r2555064648