Subject: Re: bug#18752: 24.3.94; Why is Cygwin Emacs 2x quicker than Windows Emacs?

From: Eli Zaretskii <[email-masked]>
Date: Sat, 18 Oct 2014 19:17:39 +0300

> Date: Sat, 18 Oct 2014 18:11:53 +0200
> From: Dani Moncayo <[email-masked]>
> Cc: Eli Zaretskii <[email-masked]>, [email-masked]
> 
> > Dani, can you build an optimized version as well next time?
> 
> I could, yes.  But before, I'd like to understand what are the
> advantages and drawbacks of optimized vs unoptimized builds.  Could
> someone explain that to me, or tell me where could I read that
> information?

Unoptimized builds make debugging easier, but are about 2 - 2.5 times
slower than optimized ones.  For that reason, the usual practice is to
produce unoptimized builds for snapshots and pretests, but optimized
ones for official releases.

Latest GCC versions support a -Og optimization switch that gives you
the best of both worlds.

> Also, what should I do to produce an optimized build?  "nt/INSTALL"
> shows an example of how to configure an unoptimized build, but there
> is no example for an optimized one.  How about adding that lacking
> example to the file?

If you drop the "CFLAGS=" part, you get an optimized build by
default.  The example of that is already in nt/INSTALL, even before
the one that shows how to pass non-default CFLAGS.