Re: multi-threaded Emacs

[Giuseppe Scrivano <gscrivano@gnu.org>]

Richard M Stallman <rms@gnu.org> writes:

> I don't think we want to make such pervasive and inconvenient changes
> in the C code.  What we want, I think, is to allow thread switches
> only inside the QUIT macro.

If we don't want to do immediately all changes at one time and proceed
slowly to a real parallelism then we can start with a concurrent threads
model.  I think that concurrent threads can't be considered the final
solution, what I would like to optimize using threads is I/O bound and a
concurrent model can do it only in part.  If an Elisp primitive is
waiting for some data from a file or a socket, Emacs will hang until it
is ready.  This problem can't be solved by concurrent threads that will
switch only inside the QUIT macro.

If we will implement a concurrent threads model and introduce the QUIT
macro after it can't be used by parallel threads as accesses to shared
data must be synchronized differently.

IMHO, concurrent threads itself are not very useful, they can be useful
if considered a first step in the direction of a real parallelism.

I know it is a lot of work and the question (as in everything) is: does
benefits we will have worth this effort?

Regards,
Giuseppe