RFR: 8347817: Timeouts running test/jdk/java/lang/String/concat/HiddenClassUnloading.java with fastdebug builds

[Matthias Baesken]

On Wed, 15 Jan 2025 14:14:37 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

> This PR reverts the fix from [JDK-8339166](https://bugs.openjdk.org/browse/JDK-8339166) because it increases the runtime of the test a lot.
> Instead a full gc is requested via the whitebox api. This solves the issues (see bug description) and it is also clearer and more reliable then allocating objects and classes expecting a gc because of the small heap.
> The heap setting is also removed since it is not needed anymore.
> 
> #### Testing: Duration Running HiddenClassUnloading with fastdebug Builds
> 
> I'm giving the minimum of a few runs because durations vary by +/- 10s.
> 
> 
> Linux / x86_64:
> After JDK-8339166:    3m15s
> JDK-8339166 reverted:   50s
> PR:                     50s
> 
> macOS / M1:
> After JDK-8339166:    2m30s
> JDK-8339166 reverted:   30s
> PR:                     30s
> 
> Linux / ppc64le
> After JDK-8339166:    12m30s
> JDK-8339166 reverted:  2m30s  (failure: no classes unloaded)
> PR:                    2m30s  (success)

LGTM;  probably you do not need 2000 iterations now with the full GC, a smaller number would do as well, correct ?  But it is okay for me as it is.

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Marked as reviewed by mbaesken (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/23137#pullrequestreview-2563767103