Re: semantics of thread-signal

[Eli Zaretskii]

> From: Juliusz Chroboczek <address@hidden>
> Date: Mon, 12 Dec 2016 02:21:38 +0100
> 
>     However, the Emacs thread support has been designed in a way to
>     later allow more fine-grained concurrency, and correct programs
>     should not rely on cooperative threading.
> 
> So if thread-signal can be delivered asynchronously, this will cause
> trouble when Emacs moves to kernel threads.
> 
> (And this does happen.  Viz. SBCL, CCL, ACL, all of which switched from
> userspace threading to kernel threads sometime in the last 20 years or
> so.)

The current implementation already uses kernel threads, it just makes
sure only one of them runs Lisp at any given time.  All the rest are
stuck either in system calls or trying to acquire a global lock.