GNU bug report logs - #20352
Factor 2 slow down of font-locking in c-mode

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 20352 in the body.
You can then email your comments to 20352 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
To: bug-gnu-emacs <at> gnu.org
Subject: Factor 2 slow down of font-locking in c-mode
Date: Thu, 16 Apr 2015 21:41:08 -0400

Package: Emacs
Version: 25.0.50


   src/emacs -Q -nw src/xdisp.c 					 \
       --eval "(progn (font-lock-fontify-region (point-min) (point-max)) \
                      (kill-emacs))"

Is about twice as slow with the code from "master" as it is with the
code from the emacs-24 branch.


        Stefan




In GNU Emacs 25.0.50.1 (x86_64-unknown-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2015-04-14 on pastel
Repository revision: 12f00667ebea0fe4c1e173f9d15192c75471d9d3
Windowing system distributor `The X.Org Foundation', version 11.0.11604000
System Description:	Debian GNU/Linux 8.0 (jessie)

Configured using:
 `configure -C --enable-checking --enable-check-lisp-object-type
 'CFLAGS=-Wall -g3 -Og -Wno-pointer-sign'
 PKG_CONFIG_PATH=/home/monnier/lib/pkgconfig'

Configured features:
XAW3D XPM JPEG TIFF GIF PNG SOUND GPM DBUS NOTIFY GNUTLS LIBXML2
FREETYPE M17N_FLT LIBOTF XFT ZLIB

Important settings:
  value of $LANG: fr_CH.UTF-8
  locale-coding-system: utf-8-unix

Major mode: InactiveMinibuffer

Minor modes in effect:
  csv-field-index-mode: t
  shell-dirtrack-mode: t
  c-electric-flag: t
  diff-auto-refine-mode: t
  electric-pair-mode: t
  url-handler-mode: t
  global-reveal-mode: t
  reveal-mode: t
  auto-insert-mode: t
  savehist-mode: t
  minibuffer-electric-default-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  global-prettify-symbols-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t

Recent messages:
Continuing.
up-list: Search failed: "mapconcat"
Mark set
Auto-saving...
Saving file /home/monnier/src/emacs/work/lisp/progmodes/etags.el...
Wrote /home/monnier/src/emacs/work/lisp/progmodes/etags.el
Undo! [2 times]
Mark set
user-error: No next conflict
user-error: No previous conflict

Load-path shadows:
/home/monnier/src/emacs/elpa/packages/ada-mode/ada-ref-man hides /home/monnier/src/emacs/elpa/packages/ada-ref-man/ada-ref-man
/home/monnier/src/emacs/elpa/packages/ada-mode/ada-prj hides /home/monnier/src/emacs/work/lisp/progmodes/ada-prj
/home/monnier/src/emacs/elpa/packages/ada-mode/ada-stmt hides /home/monnier/src/emacs/work/lisp/progmodes/ada-stmt
/home/monnier/src/emacs/elpa/packages/ada-mode/ada-mode hides /home/monnier/src/emacs/work/lisp/progmodes/ada-mode
/home/monnier/src/emacs/elpa/packages/ada-mode/ada-xref hides /home/monnier/src/emacs/work/lisp/progmodes/ada-xref
/home/monnier/src/emacs/elpa/packages/crisp/crisp hides /home/monnier/src/emacs/work/lisp/obsolete/crisp

Features:
(cal-french diary-lib diary-loaddefs cal-move org-timer org-table
org-colview org-clock org-attach org-id org-archive org-agenda org-rmail
org-mhe org-irc org-info org-gnus org-docview doc-view jka-compr
image-mode org-bibtex bibtex org-bbdb org-w3m reporter org org-macro
org-footnote org-pcomplete org-list org-faces org-entities org-version
ob-emacs-lisp ob ob-tangle ob-ref ob-lob ob-table ob-exp org-src ob-keys
ob-comint ob-core ob-eval org-compat org-macs org-loaddefs cal-menu
calendar cal-loaddefs derived csv-mode mule-util network-stream nsm
starttls tls mpc vc-annotate log-view vc-bzr vc-src vc-sccs vc-svn
vc-cvs vc-rcs vc-dir reposition shell pcomplete grep etags xref sort
mail-extr emacsbug semantic/bovine/c semantic/db-mode
semantic/decorate/include semantic/decorate/mode semantic/decorate pulse
semantic/bovine/c-by semantic/lex-spp semantic/idle semantic/bovine/gcc
semantic/dep semantic/bovine semantic/analyze/refs semantic/db-find
semantic/db-ref semantic/analyze semantic/sort semantic/scope
semantic/analyze/fcn semantic/db eieio-base semantic/ctxt
semantic/format semantic/tag-ls semantic/find semantic/util-modes
semantic/util semantic semantic/tag semantic/lex semantic/fw mode-local
cedet hideif cpp cmacexp cc-mode cc-fonts cc-guess cc-menus cc-cmds
cc-styles cc-align cc-engine cc-langs cc-vars cc-defs compile log-edit
message sendmail dired format-spec rfc822 mml mml-sec mm-decode
mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums
mailabbrev mail-utils mailheader pcvs-util bug-reference add-log ffap
misearch multi-isearch smerge-mode whitespace executable copyright
xscheme unsafep trace testcover shadow scheme re-builder profiler
inf-lisp ielm pp comint ansi-color ring gmm-utils ert ewoc debug elp
edebug cl-indent cus-edit cus-start cus-load wid-edit vc vc-dispatcher
vc-git diff-mode filecache eieio-opt speedbar sb-image ezimage dframe
find-func server noutline outline easy-mmode flyspell ispell checkdoc
thingatpt help-mode load-dir elec-pair url-handlers url-parse
auth-source eieio warnings eieio-core cl-generic byte-opt bytecomp
byte-compile cl-extra seq cconv gnus-util time-date mm-util mail-prsvr
password-cache url-vars reveal autoinsert proof-site proof-autoloads
cl-macs cl gv pg-vars savehist minibuf-eldef disp-table edmacro kmacro
cl-loaddefs pcase cl-lib advice help-fns info easymenu finder-inf
package epg-config bbdb-autoloads agda2 vm-autoloads tooltip eldoc
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax font-core frame cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic
indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple
abbrev minibuffer cl-preloaded nadvice loaddefs button faces cus-face
macroexp files text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget hashtable-print-readable backquote
make-network-process dbusbind inotify dynamic-setting
font-render-setting x-toolkit x multi-tty emacs)

Memory information:
((conses 8 651814 116033)
 (symbols 24 38858 3) (miscs 20 18909 1482) (strings 16 119446 20729)
 (string-bytes 1 3435542)
 (vectors 8 69693) (vector-slots 4 2293433 165150) (floats 8 749 960)
 (intervals 28 67097 2488)
 (buffers 520 87) (heap 1024 583857 25828))

Message #10 received at 20352 <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: 20352 <at> debbugs.gnu.org
Cc: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
Subject: Re: bug#20352: Factor 2 slow down of font-locking in c-mode
Date: 17 Apr 2015 19:10:05 -0000

In article <mailman.852.1429234928.904.bug-gnu-emacs <at> gnu.org> you wrote:
> Package: Emacs
> Version: 25.0.50


>   src/emacs -Q -nw src/xdisp.c                                          \
>       --eval "(progn (font-lock-fontify-region (point-min) (point-max)) \
>                      (kill-emacs))"

> Is about twice as slow with the code from "master" as it is with the
> code from the emacs-24 branch.

Twice as slow, eh?  You should be so lucky!  I've just tried it, and for
me it's nearer a factor of 10.  ;-(

I'll look at this.

>        Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).

Message #13 received at 20352 <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
Cc: 20352 <at> debbugs.gnu.org
Subject: Re: bug#20352: Factor 2 slow down of font-locking in c-mode
Date: Sat, 18 Apr 2015 17:32:34 +0000

Hello again, Stefan.

Apologies for some misinformation in my previous post.  My timings for
the master branch were on an Emacs configured with no compiler
optimisation.   When I reconfigure and rebuild with default optimisation
the figures look like....

On Sat, Apr 18, 2015 at 09:45:52AM +0000, Alan Mackenzie wrote:
> On Sat, Apr 18, 2015 at 12:35:19AM -0400, Stefan Monnier wrote:
> > > Twice as slow, eh?  You should be so lucky!  I've just tried it, and for
> > > me it's nearer a factor of 10.  ;-(

> > My original case (M-x swiper RET when in src/xdisp.c, while running my
> > locally hacked Emacs on my desktop with all debugging enabled) seemed to
> > be also way past a factor 2 (it just seemed like it would never end and
> > did not have the patience to wait for it to finish), so
> > I made a measurement on a dedicated machine where I recompiled the
> > unadulterated Emacs with default flags and all and got a "disappointing"
> > factor of 2, which still seemed significant enough.

> Some figures:  I tried running (with M-:)
> (let ((start (float-time)))
>   (font-lock-fontify-region (point-min) (point-max))
>   (- (float-time) start))
> on xdisp.c, freshly loaded before each attempt, with 2 versions of Emacs
> and 2 versions of CC Mode.  Here are the timings (in seconds):

> Released Emacs-24.5
>   Emacs-24.5's CC Mode:      29.82369565963745
>   savannah master's CC Mode: 55.37644958496094
> savannah Master
>   Emacs-24.5's CC Mode:      109.47807884216309
>   savannah Master's CC Mode: 241.9050052165985

savannah Master compiled with default optimisation
  Emacs-24.5's CC Mode:      28.840153694152832
  savannah Master's CC Mode: 55.49798059463501

So you were right - the master branch's CC Mode is fontifying at half
speed.  I'm doing some bisecting to try and find the commit which did
this.

> .  So it seems that some changes in CC Mode and some other changes
> outside of CC Mode are both to blame, here.

No, it's a CC Mode thing only.

> >         Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).

Message #18 received at 20352-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Alan Mackenzie <acm <at> muc.de>
Cc: 20352-done <at> debbugs.gnu.org, Stefan Monnier <monnier <at> IRO.UMontreal.CA>
Subject: Re: Factor 2 slow down of font-locking in c-mode
Date: Mon, 16 May 2016 10:28:57 -0700

I just now ran Stefan's benchmark on emacs-25 (commit 
9ca5dbf947a7421d37b3e2d2bc6b8d2c9218bc65) and on my platform (Fedora 23 
x86-64) Emacs 25 is now a bit faster than Emacs 24.5, as the benchmark 
took about 29 s on Emacs 24.5 and about 27 s on Emacs 25. I used the 
Emacs 25 src/xdisp.c in both benchmarks.

Alan, I guess you fixed the performance problem at some point (thanks!). 
As it's listed as a bug blocking Emacs 25, I'm closing the bug report now.

Message #21 received at 20352 <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: Stefan Monnier <monnier <at> IRO.UMontreal.CA>, 20352 <at> debbugs.gnu.org
Subject: Re: Factor 2 slow down of font-locking in c-mode
Date: Tue, 17 May 2016 09:05:12 +0000

Hello, Paul.

On Mon, May 16, 2016 at 10:28:57AM -0700, Paul Eggert wrote:
> I just now ran Stefan's benchmark on emacs-25 (commit 
> 9ca5dbf947a7421d37b3e2d2bc6b8d2c9218bc65) and on my platform (Fedora 23 
> x86-64) Emacs 25 is now a bit faster than Emacs 24.5, as the benchmark 
> took about 29 s on Emacs 24.5 and about 27 s on Emacs 25. I used the 
> Emacs 25 src/xdisp.c in both benchmarks.

That's good to hear!

> Alan, I guess you fixed the performance problem at some point (thanks!). 
> As it's listed as a bug blocking Emacs 25, I'm closing the bug report now.

Thanks!

-- 
Alan Mackenzie (Nuremberg, Germany).

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.