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Re: CC Mode now respects users' settings of open-paren-in-column-0-is-de
Re: CC Mode now respects users' settings of open-paren-in-column-0-is-defun-start.
Sun, 15 Nov 2015 22:14:44 +0000
On Thu, Nov 12, 2015 at 06:09:39PM +0000, Alan Mackenzie wrote:
> > So far, the performance didn't improve significantly. Either there are
> > other changes that did make editing C deteriorate considerably over the
> > past two years or I still have to tweak some internal settings. I'll
> > get back to you as soon as I know more.
> I noticed a large degradation in speed, too. I timed the complete
> fontification of xdisp.c, and Emacs 24.5 was taking ~40s (with
> o-p-i-c-0-i-defun-start t). The same on Emacs 25.1 is taking ~77s. The
> difference seems to be between standalone CC Mode and the version
> included with Emacs 25.1. There's some bug on savannah CC Mode which
> hasn't been fixed, or some optimisation which hasn't been made.
> (Somewhat later). The standalone CC Mode doesn't (in the default
> branch) contain certain C++11 enhancements. These seem to be what is
> slowing things down. This should be easily fixable for C Mode, but it
> would be nice to fix it for C++ Mode, too.
I've just committed a fix (to the emacs-25 branch), mainly for C++ Mode,
but also for C Mode, too.
When I time the scrolling through xdisp.c, with the fix it now takes
~42s. Without the fix, it's around 77s. Here's the program I used to
time with (you need to initialise C Mode each time you rerun the test,
of course, to reinitialise Font Lock Mode):
(defmacro time-it (&rest forms)
"Time the running of a sequence of forms using `float-time'.
Call like this: \"M-: (time-it (foo ...) (bar ...) ...)\"."
`(let ((start (float-time)))
(- (float-time) start)))
(defun time-scroll ()
> > martin
Alan Mackenzie (Nuremberg, Germany).