Multithread or multiprocess in emacs??

[Ergus]

Hi:

Very recently I have seen a code in an elpa package that starts async
subprocesses; but instead of using make-process the package uses
make-thread + process-file. This was to reduce the latency and some
lagging (not evident in my system, but apparently it annoyed the
package's author).

So, my question is now: Has anyone measured the overhead created by
make-process in critical parts of the code like flymake checkers, or
ispell? and compared with creating new threads?

If this is somehow significant maybe we may consider adding a helper
thread or thread-pool for some purposes as now the C11 standard has the
threads.h header.

Is there any work already in this direction? How does Elisp handles
multithreading?

Best,
Ergus