RFR: 8372008: TestGetTotalGcCpuTime test failures on Windows (Some GC CPU time must have been reported)

[David Holmes]

On Mon, 17 Nov 2025 20:32:52 GMT, Jonas Norlinder <jnorlinder at openjdk.org> wrote:

> Current trivial test for `TestGetTotalGcCpuTime` fails as some OSs may have a slower update rate for the underlying CPU time thread counters than the code anticipated, causing the test to fail which assumes that some work have been performed and the count should be non-zero.
> 
> Solution: All GCs we are testing are tracing GCs. Therefore, add some marking job to inflate the GC CPU time such that we can guarantee to observe a non-zero value.

Having the test actually do something that looks like it triggers GC certainly makes sense. I'm unclear what a GC's "slower update rate" means.

Thanks

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Marked as reviewed by dholmes (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28362#pullrequestreview-3475947140