Re: [harder@ifa.au.dk: Speed of all-completions]

[Andreas Schwab <schwab@suse.de>]

Richard Stallman <rms@gnu.org> writes:

> Would someone please take a look at this?
>
> From: Jesper Harder <harder@ifa.au.dk>
> Subject: Speed of all-completions
> To: emacs-pretest-bug@gnu.org
> Date: Sun, 30 May 2004 17:37:56 +0200
> X-Sent: 2 weeks, 6 hours, 17 minutes, 49 seconds ago
>
> In GNU Emacs 21.3.50.10 (i686-pc-linux-gnu, GTK+ Version 2.0.2)
>  of 2004-05-25 on defun.localdomain
>
> I use icomplete-mode and I've noticed that it feels more sluggish in
> cvs Emacs than in Emacs 21.3.
>
> Profiling shows that the bulk of the time is spent in
> `all-completions', so I tried to benchmark it with this example:
>
> (defmacro time (form)
>   `(let ((t1 (float-time)))
>     ,form
>     (- (float-time) t1)))
>
> (let ((oba (make-vector 255 0)))
>   (dotimes (i 10000)
>     (intern (format "f%i" i) oba))
>   (time
>    (all-completions "f" oba)))
>
> The time used was:
>
>   cvs Emacs:   0.16448211669921875
>   Emacs 21.3:  0.01507115364074707

This is due to this change:

	(Ftry_completion, Fall_completions, Ftest_completion): Bind
	case-fold-search to the value of completion-ignore-case when
	checking completion-regexp-list.

I've checked in a fix that avoids the overhead of specbind when
completion-regexp-list is empty.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
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