Using virtual threads

[sunmisc]

Is your feature request related to a problem?

At the moment the kernel uses OS threads, hence ThreadPools come from here

The current implementation (CachedThreadPool) allocates too many precious OS threads, to blocking I/O

This was the only solution to get good performance, but things changed with the move to jdk 21+

Describe the solution you'd like.

I tend to promote the concept of fibers in many places Paper: async chat, async scheduler (controversial) and many other places blocking I/O

This would not only simplify the code, but could seriously reduce overhead (on memory for example).

Describe alternatives you've considered.

I don't know what to write here, but I'm being asked to do it! The alternative (which is a bad solution in this case) is a coroutine boilerplate, but not as a suspend, but an Executor that doesn't park

Other

No response

[electronicboy]

virtual threads are still backed by platform threads, I really doubt that they offer a performance gain worthy of trying to patchwork these types of things, especially when most of the things using a thread pool for work which is pausable is code that is not written to utilise NIO or other mechanisms that actually support what vthreads intend to serve.

Chat itself is not really going to scale much, and so I really doubt that using vthreads here would change much given how few chat threads are often actually in play, all that would change is that we'd add yet another layer of headaches to be weary of when providing support.

[sunmisc]

Of course performance is unlikely to be higher, we are talking about the overhead of OS threads, which is better minimized to the number of hardwares on the JVM.

and the main thing is a more understandable and simple code

There shouldn't be any special problems, since they have the same semantics, and it can be implemented gradually.

The main problem is very many OS threads on blocking I/O, the OS does not know anything about the context of the task, for this reason it aggressively allocates the stack.

This can be very useful when we have many small servers (e.g. bedwars/skywars)
In order not to utilize hardwar resources too much

[MiniDigger]

please share some kind of metrics that platform threads are a bottleneck for your setup