RFR: 8324582: Replace -Djava.util.concurrent.ForkJoinPool.common.parallelism to -Djdk.virtualThreadScheduler.parallelism in jvmti vthread tests

[Alan Bateman]

On Wed, 24 Jan 2024 02:42:29 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

> Some jvmti tests use
> -Djava.util.concurrent.ForkJoinPool.common.parallelism
> to control the pool of virtual threads. However, it is controlled by
> jdk.virtualThreadScheduler.parallelism property.
> 
> The non-continuations implementation doesn't use any of these properties and it was just deleted.
> 
> I verified the fix using jcmd Thread.dump and ran all jvmti tests in the default configuration.

test/hotspot/jtreg/serviceability/jvmti/thread/GetAllThreads/allthr01/allthr01.java line 42:

> 40:  * @library /test/lib
> 41:  * @compile allthr01.java
> 42:  * @run main/othervm/native -Djdk.virtualThreadScheduler.parallelism=1 -agentlib:allthr01 allthr01

Some operations temporarily increase the parallelism, I suspect you really want maxPoolSize=1 in these tests.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17547#discussion_r1464837680