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

[Francesco Andreuzzi]

On Fri, 21 Nov 2025 15:19:54 GMT, Matthias Baesken <mbaesken 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`

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PR Review Comment: https://git.openjdk.org/jdk/pull/28455#discussion_r2553079222