RFR: 8330846: Add stacks of mounted virtual threads to the HotSpot thread dump [v15]

[Alan Bateman]

On Tue, 11 Jun 2024 21:05:38 GMT, Inigo Mediavilla Saiz <duke at openjdk.org> wrote:

>> Print the stack traces of mounted virtual threads when calling `jcmd <pid> Thread.print`.
>
> Inigo Mediavilla Saiz has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Require continuations to run the test

test/hotspot/jtreg/serviceability/dcmd/thread/PrintMountedVirtualThread.java line 54:

> 52:         output.shouldMatch(".*at " + Pattern.quote(DummyRunnable.class.getName()) + "\\.compute.*");
> 53:         output.shouldMatch("Mounted virtual thread " + "\"Dummy Vthread\"" + " #" + vthread.threadId());
> 54:         shouldFinish.set(true);

One other suggestion is to use a try-finally block here. Put L48-53 in the block and set shouldFinish in the finally block. That way if the test fails then it won't leave a spinning thread to disrupt the next test that runs in the agent VM.

Also just to say that we've mostly used JUnit for new tests in recent releases, moving away from TestNG for new tests.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19482#discussion_r1635872465