Re: [Emacs-diffs] comment-cache 223d16f 2/3: Apply `comment-depth' text properties when calling `back_comment'.

[Eli Zaretskii]

> Date: Wed, 09 Mar 2016 20:58:23 +0100
> From: martin rudalics <address@hidden>
> Cc: address@hidden, address@hidden
> 
> However, ‘foo’ is about ten times slower than for a version of Emacs
> 24.2 which is about two times slower than for a version of Emacs 23.0.
> ‘bar’ is about 5 times slower than the Emacs 24.2 version which is 3.5
> times slower than the one from Emacs 23.0.
> 
> So, for example, executing ‘bar’ for my Emacs 23.0 took 24.89 seconds
> (0.068 for an average call) versus 464.375 seconds (1.272 average) with
> the comment-cache version.  This means that performance has deteriorated
> by a factor of 18 over the past years.  This also means that I cannot
> use non-optimized builds for my daily work any more.

I concur that the current C mode is much slower than it was several
releases ago.  My personal subjective impression is that it gets
slower with every new release, and I suspect that the main reason is
our desire to support more and more C quirks and subtleties.  If this
is true, I'd be glad to go back to a simpler C mode, which sometimes
mis-fontified or even (gasp!) mis-indented an occasional rare
construct, but to get back the speed we enjoyed in the past.