Re: Emacs 23.0 is much slower starting than Emacs 22.3

[David De La Harpe Golden]

Alan Mackenzie wrote:
> Hi, David!
>
> On Thu, Oct 23, 2008 at 07:53:14AM +0100, David De La Harpe Golden wrote:
> > Alan Mackenzie wrote:
>
> > > OK, 100 random files.el.  How big were they?
>
> > Probably fairly small. I went back and did the 180 .c files from the 
> > emacs source tree, totalling 9.2MB, and that took 6-7 secs (Which was a 
> > bit slower than I expected!)
>
> OK.  Was that Emacs 22 or 23?  Presumably 23.  Any chance you could time
> it using the other Emacs?

Yes, now using "time emacs -f kill-emacs"  (warm cache this time, not
rebooting between runs...)

emacs   run     real    user    sys
22      1       4.880   3.960   0.180
22      2       4.589   3.992   0.136
22      3       4.764   4.076   0.176
23      4       7.275   6.636   0.120
23      5       6.958   6.276   0.188
23      6       6.898   6.268   0.132

So yeah, 23 is slower.

I tried just putting 180 find-file-noselects in a file and loading it
i.e.

$ find /usr/local/src/emacs -name '*.c' -printf \
    '(find-file-noselect "%p")\n' >fftest.el
$ emacs --batch --eval '(byte-compile-file "fftest.el")'
$ time emacs -l fftest.elc -f kill-emacs

emacs   run     real    user    sys
22      1       4.523   3.888   0.136
22      2       4.744   4.172   0.112
22      3       4.457   3.836   0.176
23      4       7.177   6.532   0.152
23      5       7.198   6.544   0.160
23      6       7.159   6.472   0.220


So FWIW probably the problem is in the find-file call path rather than 
anything desktop.el is doing in particular (though there IS a kinda 
dubious mapc in desktop-create-buffer, but it likely doesn't really bite 
until rather larger file counts again (triangular progression in file 
count)).