RFR: 8356848: Separate Metaspace and GC printing [v4]

[Thomas Stuefe]

On Thu, 22 May 2025 08:48:47 GMT, Joel Sikström <jsikstro at openjdk.org> wrote:

>> test/hotspot/jtreg/serviceability/dcmd/gc/HeapInfoTest.java line 48:
>> 
>>> 46:         OutputAnalyzer output = executor.execute(cmd);
>>> 47:         output.shouldNotContain("Unknown diagnostic command");
>>> 48:         output.shouldHaveExitValue(0);
>> 
>> This was already kind of weak before and is almost useless now :) can we improve on that? A command reporting back nothing would now result in a green test?
>
> I agree. It's hard to grep for specific information since most GC have different approaches to printing similar information.
> 
> However, all GCs (even Epsilon) print the string "used", so maybe grepping for that is a reasonable approach, just to see that something is printed?

Heap.info is important; we should have better tests for this. But we can hold this off for a separate PR, so I am fine with scanning for "used".

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PR Review Comment: https://git.openjdk.org/jdk/pull/25214#discussion_r2103784060