Experiencing an issue with ScheduledExecutorService alongside VT

[Yuval Lombard]

Hi Alan,

By "So I
think you are running into a bug.." do you mean on my end? (Hope you do 😅)

When scheduling my tasks with platform threads I dont see it is being
reproduced, although I must say my current platform threads scheduler is
different (quartz scheduler) and does not make use of semaphores (but
instead it pools its workers) that is why I suspect my usage of semaphores
with VT.

Also when I try to execute the vthread_summary command you suggested I get
this error:
java.lang.IllegalArgumentException: Unknown diagnostic command

I will certainly do as you suggest and try to upgrade the java version to
the latest ea, but I really want to make sure I am not doing anything
stupid and missing something before I do that

On Sun, 21 Jul 2024 at 20:32, Alan Bateman <Alan.Bateman at oracle.com> wrote:

> On 21/07/2024 18:10, Yuval Lombard wrote:
> > Hi Robert
> >
> > Thanks for your reply and feedback.
> > Unfortunately I have no choice but using the MQTT 3rd party lib
> >
> > Attaching also the jcmd thread dump as you suggested.
> > Hope it would be helpful
>
> There are 120k virtual threads. Most of them have empty stack traces  so
> I assume they have been started but haven't executed yet. The dump is
> hinting that it is something timer related. There are two virtual
> threads (#1561853 and #1561856) doing Socket.connect with a timeout and
> both are scheduling to be unparked if their connection isn't established
> before the timeout expires. At the same time, some other virtual thread
> (not sure which) has just unmounted from ForkJoinPool-1-worker-4 due to
> contention trying to enter a monitor. ForkJoinPool-1-worker-4 is attempt
> to schedule the virtual thread to unblocked after a short delay. So I
> think you are running into a bug but I think we need to see if
> duplicates with the more recent EA build.
>
> -Alan
>
>

-- 

Kind regards,

*Yuval Lombard*

*Lead Software Engineer*

+972.50.548.0111

yuval.l at securithings.com

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