Re: Skipping unexec via a big .elc file

[Eli Zaretskii]

> Date: Sat, 24 Dec 2016 15:37:11 +0200
> From: Eli Zaretskii <address@hidden>
> Cc: address@hidden
> 
> I’m still hitting just under 0.2s for:
> 
> >   time ./temacs --batch --eval '(progn (message "hi") (kill-emacs))'
> > 
> > on Linux/GNU/X11 (Intel Core i5-2320, 3GHz, gcc 4.9); my Mac (Intel Core 2 
> > Duo, 2.8GHz) takes over half a second (including at least one GC 
> > invocation).
> 
> For the record, my timing is 0.828s with an unoptimized build of the
> branch, as opposed to 13.2s with an unoptimized build on master, and
> 5.343s with an optimized (-Og) build of Emacs 25.1.90.  The CPU is
> Core i7-2600, 3.4GHz; the compiler used is GCC 5.3.0.

With an optimized (-O2) build on the same system, the above command
takes 0.190s on the average.  Byte-compiling Lisp files in batch mode
shows that loading dumped.elc takes about 0.150s, as that is the
difference between byte-compiling with temacs and the dumped emacs.
For example, compiling simple.el takes 0.656s with temacs and 0.515s
with dumped emacs.  IOW, the overhead is additive, as expected.