Is there any way to inspect the executor (?) used by aleph after the server is started? I'd want to log the number of threads used to handle requests
Yes. I'm away at the moment, but poke around the code, you should be able to find what you need.
And on a related note: is there (plans for) a loom virtual thread based executor in (addition to) Dirigiste?
I looked into loom a while back, and it's doable, but no further investigation has been done. The Netty side wouldn't change probably, since it already uses cores pretty efficiently. On the manifold side, a vthread executor could be swapped in, and it may or may not be beneficial. It's not an obvious win, which is why I hadn't gotten around to it