GNU bug report logs - #14051
Fwd: 24.3; Slow scrolling in term modes

Please note: This is a static page, with minimal formatting, updated once a day.
Click here to see this page with the latest information and nicer formatting.

Package: emacs; Reported by: Bryan Bishop <bryanjbishop@HIDDEN>; dated Mon, 25 Mar 2013 15:00:03 UTC; Maintainer for emacs is bug-gnu-emacs@HIDDEN.

Message received at submit <at>

Received: (at submit) by; 25 Mar 2013 14:59:07 +0000
From debbugs-submit-bounces <at> Mon Mar 25 10:59:07 2013
Received: from localhost ([]:44845
	by with esmtp (Exim 4.72)
	(envelope-from <debbugs-submit-bounces <at>>)
	id 1UK8rZ-0008Oq-OP
	for submit <at>; Mon, 25 Mar 2013 10:59:06 -0400
Received: from ([]:33596)
	by with esmtp (Exim 4.72)
	(envelope-from <kc0rjx@HIDDEN>) id 1UJzHA-0001Pc-Ff
	for submit <at>; Mon, 25 Mar 2013 00:44:54 -0400
Received: from Debian-exim by with spam-scanned (Exim 4.71)
	(envelope-from <kc0rjx@HIDDEN>) id 1UJzEy-0001Al-8g
	for submit <at>; Mon, 25 Mar 2013 00:42:40 -0400
X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on
X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00,FORGED_YAHOO_RCVD,
	FREEMAIL_FROM,T_DKIM_INVALID autolearn=no version=3.3.2
Received: from ([]:38731)
	by with esmtp (Exim 4.71)
	(envelope-from <kc0rjx@HIDDEN>) id 1UJzEy-0001Ah-5B
	for submit <at>; Mon, 25 Mar 2013 00:42:36 -0400
Received: from ([]:44930)
	by with esmtp (Exim 4.71)
	(envelope-from <kc0rjx@HIDDEN>) id 1UJzEt-0000Fe-T0
	for bug-gnu-emacs@HIDDEN; Mon, 25 Mar 2013 00:42:36 -0400
Received: from Debian-exim by with spam-scanned (Exim 4.71)
	(envelope-from <kc0rjx@HIDDEN>) id 1UJzEo-00019R-UC
	for bug-gnu-emacs@HIDDEN; Mon, 25 Mar 2013 00:42:31 -0400
Received: from ([2a00:1450:4010:c03::22d]:40845)
	by with esmtp (Exim 4.71)
	(envelope-from <kc0rjx@HIDDEN>) id 1UJzEo-00019H-I3
	for bug-gnu-emacs@HIDDEN; Mon, 25 Mar 2013 00:42:26 -0400
Received: by with SMTP id er20so10600810lab.18
	for <bug-gnu-emacs@HIDDEN>; Sun, 24 Mar 2013 21:42:25 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20120113;
X-Received: by with SMTP id em5mr5318027lbb.1.1364186545285; Sun,
	24 Mar 2013 21:42:25 -0700 (PDT)
MIME-Version: 1.0
Received: by with HTTP; Sun, 24 Mar 2013 21:42:10 -0700 (PDT)
In-Reply-To: <CAPAn_E3hDyk=O+Bwi3mLbCfXkUaxTHXW35ihGgTUK-oAZqOpbw@HIDDEN>
References: <CAPAn_E3hDyk=O+Bwi3mLbCfXkUaxTHXW35ihGgTUK-oAZqOpbw@HIDDEN>
From: Bryan Bishop <bryanjbishop@HIDDEN>
Date: Sun, 24 Mar 2013 23:42:10 -0500
X-Google-Sender-Auth: A58Nj-t-kr-e4AFz88KGO0DqXtw
Message-ID: <CAPAn_E3kH=32mpazeaHsOve-SM0BbAa8rTb2RD=EOhiUA3VfDQ@HIDDEN>
Subject: Fwd: 24.3; Slow scrolling in term modes
To: bug-gnu-emacs@HIDDEN
Content-Type: text/plain; charset=UTF-8
X-detected-operating-system: by Error: Malformed IPv6 address
	(bad octet value).
X-detected-operating-system: by GNU/Linux 2.6.x
X-Spam-Score: -4.5 (----)
X-Debbugs-Envelope-To: submit
X-Mailman-Approved-At: Mon, 25 Mar 2013 10:59:01 -0400
X-BeenThere: debbugs-submit <at>
X-Mailman-Version: 2.1.13
Precedence: list
List-Id: <>
List-Unsubscribe: <>,
	<mailto:debbugs-submit-request <at>>
List-Archive: <>
List-Post: <mailto:debbugs-submit <at>>
List-Help: <mailto:debbugs-submit-request <at>>
List-Subscribe: <>,
	<mailto:debbugs-submit-request <at>>
Sender: debbugs-submit-bounces <at>
Errors-To: debbugs-submit-bounces <at>
X-Spam-Score: -4.5 (----)

This bug report will be sent to the Bug-GNU-Emacs mailing list
and the GNU bug tracker at  Please check that
the From: line contains a valid email address.  After a delay of up
to one day, you should receive an acknowledgment at that address.

Please write in English if possible, as the Emacs maintainers
usually do not have translators for other languages.

Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':

The window scrolling performance ("multi-term" and plain old "term" in
this case) in emacs 24 is terrible after a few thousand lines of
scrollback, slowly getting worse and worse and after about 5000 lines of
scrollback takes about a 1/2 second to render the next chunk of text.

How I can replicate the problem:

emacs -Q
M-x term
find /

(The output of the find command whizzes by, and then starts to get jerky
and slow when scrollback history is > 2000 lines)

I've installed the stock emacs24 from linux mint/ubuntu packages
(24.1.1), and a custom
compiled version of 24.3.1 without any special tricks and a compiler
option of -O3 and the term mode behavior is all the same, and this
behavior even shows up with "emacs -Q".

It seems the same with multi-term, ansi-term, nterm, it doesn't matter.
This does work very fast in eshell and in terminal-emulator mode.
What is weird is ALL the terminal modes in Emacs 23 seem to work
great, but not Emacs 24.

Any ideas how I can make this mode faster?  My suspicion was around
font-lock-mode but I've turned that off with no effect.  The fact that
it is still slow without my init file using -Q and seems to be really
fast in Emacs 23 has me stumped.

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file

In GNU Emacs 24.3.1 (x86_64-unknown-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2013-03-13 on badwolf
Windowing system distributor `The X.Org Foundation', version 11.0.11300000
System Description:    Linux Mint 14 Nadia

Configured using:
 `configure '--prefix=/usr/local' 'CFLAGS=-O3''

Important settings:
  value of $LC_CTYPE: en_US.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Buffer Menu

Minor modes in effect:
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-x 1 M-x t e r m <return> <return>
f i n d <return> C-c C-c C-c C-c C-c C-c e x i t <return>

Recent messages:
byte-code: Beginning of buffer [14 times]
Quit [2 times]
Mark set
Already sent message via mail; resend? (y or n)  y
Mark set [2 times]
Sending via mail...
Mark set
Saved text from "The window scrolling performance ("multi"

Load-path shadows:
None found.

(mule-util mailalias mailclient browse-url cus-edit cus-start cus-load
wid-edit shadow sort gnus-util mail-extr emacsbug message format-spec
rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils term disp-table ehelp electric ring
help-mode easymenu time-date tooltip ediff-hook vc-hooks lisp-float-type
mwheel x-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list newcomment lisp-mode register page menu-bar rfn-eshadow
timer select scroll-bar mouse jit-lock font-lock syntax facemenu
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 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 dynamic-setting system-font-setting
font-render-setting x-toolkit x multi-tty emacs)

Acknowledgement sent to Bryan Bishop <bryanjbishop@HIDDEN>:
New bug report received and forwarded. Copy sent to bug-gnu-emacs@HIDDEN. Full text available.
Report forwarded to bug-gnu-emacs@HIDDEN:
bug#14051; Package emacs. Full text available.
Please note: This is a static page, with minimal formatting, updated once a day.
Click here to see this page with the latest information and nicer formatting.
Last modified: Fri, 31 Oct 2014 17:00:04 UTC

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