M-x grep significantly slower in emacs 22 (compared to emacs 21)

[Philippe Waroquiers]

M-x grep (on a big file) is much slower with emacs 22 than with emacs 21.
I verified this on an emacs 22 compiled on hp-ux
and on emacs 22 compiled on gnu/linux.
The grep returns about 1900 lines.

performances on gnu-linux (x86, 3 GHz) (elapsed time)
emacs 21: +-2 seconds
emacs 22: +-10 seconds

performances on hp (pa-risc workstation, 400 Mhz) (elapsed time)
emacs 21: +-10 seconds
emacs 22: +-82 seconds

While the M-x grep was running (for the hp test), I used the "top" command 
to see what was going on. 
grep was sleeping most of the time, and emacs was sleeping then running
then sleeping then running. The proportion of sleep time was significant
(I would say: about 80% of the time sleeping).

Note that it is not the grep itself that takes the time, here is the
time taken by the grep on hp:
wao@gull: time grep FILE: tacot1* | wc
1905 24765 250652

real    0m0.78s
user    0m0.63s
sys     0m0.12s
wao@gull:



In GNU Emacs 22.1.1 (hppa1.1-hp-hpux11.11, Motif Version 2.1.0)
 of 2007-09-21 on steer
Windowing system distributor `Hewlett-Packard Company', version 11.0.600000
configured using `configure  'hppa1.1-hp-hpux11.11' 
'--prefix=/cm/ot/TOOL/GNU!ESF.EMACS_STUFF/build_G!67.IP.11/generated' 
'--exec-prefix=/cm/ot/TOOL/GNU!ESF.EMACS_STUFF/build_G!67.IP.11/generated/libexec/emacs-22.1'
 '--mandir=/cm/ot/TOOL/GNU!ESF.EMACS_STUFF/build_G!67.IP.11/generated/man' 
'--with-gcc=no' '--with-xpm' '--with-x11r6' '--with-x-toolkit=motif' 
'--x-libraries=/usr/lib/X11R6:/usr/contrib/X11R6/lib' 
'build_alias=hppa1.1-hp-hpux11.11' 'host_alias=hppa1.1-hp-hpux11.11' 
'target_alias=hppa1.1-hp-hpux11.11' 'CFLAGS=-Ae +O2 +DA1.1' 'LDFLAGS= 
-L/cm/ot/TOOL/GNU!ESF.EMACS_STUFF/build_G!67.IP.11/generated/work/emacs-22.1/xpm-3.4k/lib'
 
'CPPFLAGS=-I/cm/ot/TOOL/GNU!ESF.EMACS_STUFF/build_G!67.IP.11/generated/work/emacs-22.1/xpm-3.4k
 ''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  locale-coding-system: nil
  default-enable-multibyte-characters: nil

Major mode: Lisp Interaction

Minor modes in effect:
  iswitchb-mode: t
  show-paren-mode: t
  which-function-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t

Recent input:
<help-echo> <down-mouse-1> <mouse-1> <help-echo> <help-echo> 
<menu-bar> <help-menu> <report-emacs-bug>

Recent messages:
Loading cl-macs...done
Loading gnuserv-compat...done
isearch-forwardisearch-backwardisearch-forward-regexpisearch-backward-regexpquery-replacequery-replace-regexpreplace-regexpreplace-string
Loading gnat-fix-error...done
Loading version_emacs_startup...done
Loading 
/cm/ot/TOOL/GNU!ESF.EMACS_STUFF/build_G!67.IP.11/generated/share/emacs/22.1/site-lisp/emacs_startup.el
 (source)...done
Loading easy-mmode...done
Loading cl-seq...done
For information about the GNU Project and its goals, type C-h C-p.
Loading emacsbug...done


-- 
Philippe WAROQUIERS                  Eurocontrol - Central Flow Management Unit
philippe.waroquiers@eurocontrol.int  Rue de la fusee, 96
Tel: +32 2 729 97 35                 1130 Brussels
Fax: +32 2 729 90 22                 Belgium
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