bug#66288: 29.1; Performance regression using pipe for subprocess

[Eli Zaretskii]

> Cc: gerd.moellmann@gmail.com, dmitry@gutov.dev, 66288@debbugs.gnu.org
> Date: Tue, 03 Oct 2023 09:22:44 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > One other thing comes to mind: is it possible that this is a problem 
> > with native compilation? I built both 28.2 and 29.1 to use native 
> > compilation. Did anything relevant change in 29.1?
> 
> It's unlikely to matter, but to eliminate this variable, please try
> building without native-compilation and see if the difference
> persists.

One other thing to try is to disable encoding and decoding of the text
we exchange with the subprocess.  Like this:

  emacs -Q
  M-x load-library RET xscheme RET
  C-x RET c no-conversion RET M-x run-scheme RET

and see if this performs better than what you see by default.