Significant degradation of Thread.sleep with virtual threads in JDK 25 vs JDK 21

[Alan Bateman]

On 21/11/2025 15:52, Fredriksson, Christian wrote:
>
> Hey,
>
> I believe I have found a bug with JDK 25 and virtual threads, but will 
> need some guidance in what information I need to provide in order to 
> file a bug.
>
> Short version: after changing from JDK 21 to JDK 25, doing 
> Thread.sleep(1) in a virtual thread now sometimes takes up to 60 
> seconds (!).
>
>
Thanks for the mail. Do you have a standalone test that uses the loop in 
your mail that we could use to study this?  The timer support has 
changed significantly twice between JDK 21 and JDK 25. From your mail 
then it could be a pathological case that leads to starvation, or it 
could be related to recently reported bug [1].

-Alan

[1] https://bugs.openjdk.org/browse/JDK-8370887
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