bug#24953: 25.1; Possible inefficiency in UTF-8

[Eli Barzilay]

In an empty buffer, insert a pile of "foo" lines (a few screens high),
in the middle, add the result of (insert #x23ce) (to get the unicode
character).  Now `C-x RET l' and "UTF-8".  Now, just moving the cursor
around in the buffer shows very noticeable delays, up to more than a
second.  In the default language of "English" I don't see that
happening.  This is on a Windows 7 machine.




In GNU Emacs 25.1.1 (x86_64-w64-mingw32)
 of 2016-09-17 built on LAPHROAIG
Windowing system distributor 'Microsoft Corp.', version 6.1.7601
Configured using:
 'configure --without-dbus --without-compress-install CFLAGS=-static'

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS

Important settings:
  value of $LC_COLLATE: POSIX
  value of $LANG: en_US.UTF-8
  locale-coding-system: cp1252

Major mode: Text

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-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
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
next-line: End of buffer [9 times]
previous-line: Beginning of buffer [6 times]
Mark set [90 times]
previous-line: Beginning of buffer [10 times]
You can run the command ‘set-language-environment’ with C-x RET l
Auto-saving...done
next-line: End of buffer [11 times]
previous-line: Beginning of buffer [10 times]
next-line: End of buffer [9 times]
Making completion list...

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message idna dired format-spec rfc822
mml mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util help-fns help-mode easymenu
cl-loaddefs pcase cl-lib mail-prsvr mail-utils time-date mule-util
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel dos-w32 ls-lisp disp-table w32-win w32-vars term/common-win
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 facemenu font-core
frame cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan
thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian
slovak czech european ethiopic indian cyrillic chinese charscript
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 w32notify w32 multi-tty
make-network-process emacs)

Memory information:
((conses 16 91694 5152)
 (symbols 56 19958 0)
 (miscs 48 116 129)
 (strings 32 16382 3241)
 (string-bytes 1 443818)
 (vectors 16 11828)
 (vector-slots 8 426659 5914)
 (floats 8 164 74)
 (intervals 56 442 840)
 (buffers 976 25))

-- 
                   ((x=>x(x))(x=>x(x)))                  Eli Barzilay:
                   http://barzilay.org/                  Maze is Life!