RFR: 8297286: runtime/vthread tests crashing after JDK-8296324 [v5]

[Serguei Spitsyn]

On Fri, 24 Mar 2023 19:13:39 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> It is needed to balance enabling/disabling notifyJvmti mode with the ThreadStart/VirtualThreadStart events.
>> Otherwise, many mode switches can be observed without any events which is not interesting.
>> We need to allow virtual threads to execute a little bit after a mode switch.
>
> Shouldn't that be the caller's responsibility? Including a comment would be helpful.

Okay, moved to the caller. In fact, I've refactored the test even more for safety purposes. Will describe it separately.

>> Good question. We almost always do it in the JVMTI tests including `serviceability/jvmti/vthread` and `vmTestbase/nsk/jvmti` tests. Examples are 22 `serviceability/jvmti/vthread` tests.
>
> Are you saying it's not needed, but you included it to be consistent with other tests?

I remember it was really needed some time ago but do not remember why.
Removed it now. Then we have a technical debt to get rid of this in all JVMTI tests with the `-agentlib` option.

>> I'm not sure if it is really needed. 60 virtual threads are started.
>> Some of them are executed long enough before shutdown.
>> We can just increase the number of threads if necessary.
>
> ok

I've refactored the test, and it has impacted this fragment. Please, see my comment above.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13133#discussion_r1149968287
PR Review Comment: https://git.openjdk.org/jdk/pull/13133#discussion_r1149967613
PR Review Comment: https://git.openjdk.org/jdk/pull/13133#discussion_r1149969217