Re: Emacs 23.0 is much slower starting than Emacs 22.3

[David De La Harpe Golden]

Stefan Monnier wrote:
> > Most of the latter is in "hack-project-variables", and most of /that/ is
> > "project-find-settings-file", and most of that is the
> > "locate-dominating-file" walk.
>
> locate-dominating-file (or rather some equivalent code) is also used in
> VC to detect the revision control system used for the file.
> It's actually used 5 times there (once each for Bzr Git Hg Mtn Arch), so
> are you sure only the one in project-find-settings-file costs us
> the slowdown?  

Not all of it, but it seems to be significant.

taking out locate-dominating-file with:
(defun locate-dominating-file (file regexp) nil)

runs just now (one after the other, no reboot, so probably
from OS cache anyway)

emacs   l-d-f   realtime
22      n/a     4.921
23      off     6.188
23      on      7.500

Taking out hack-project-variables as a whole similarly

emacs   h-p-v   realtime
23      off     6.079

So it's about 1/2 the slowdown?

Then I set vc-handled-backends to nil (not sure that stops
vc searching totally, mind):

emacs vc-h-b    h-p-v   realtime
23    off       off     5.503
23    off       on      7.189