bug#8248: 23.2; Emacs 23.2 very slow over ssh when vertical-scroll-bar is enabled

bug#8248: 23.2; Emacs 23.2 very slow over ssh when vertical-scroll-bar is enabled

[obh]

When vertical-scroll-bar is enabled on emacs 23.2 and used over ssh -X
then switching buffers (^X ^B) takes several seconds. Likewise
scrolling, changing windows etc. is very sluggish. I have a 12/5 Mbps
cable line between work/home with usually 8-12ms ICMP rtt. Plenty of
available bandwidth and CPU.

Emacs feels a lot mot snappy and is usable when starting 'emacs -xrm
'*verticalScrollBars: off'.

I found the following (old) bug report in emacs bug database that
probably describes this bug:

  http://debbugs.gnu.org/cgi/bugreport.cgi?bug=6429

When googling 'emacs ssh latency' there seems to be more people
having this problem and the prevalent advise was to use use server
fonts and not client fonts. I tried to compile emacs with
'--without-xft' but with no visibly speedup.

  http://groups.google.com/group/gnu.emacs.help/browse_thread/thread/8bf4914f3a7ae7e5
  http://groups.google.com/group/gnu.emacs.help/browse_frm/thread/bd7e102326bec6b2/dd8706c921a0ef8c?tvc=1#dd8706c921a0ef8c


Kind regards,

Ole Bjorn Hessen


---




In GNU Emacs 23.2.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.10.4)
 of 2011-03-03 on asol1.nm1.telenor.net
Windowing system distributor `The X.Org Foundation', version 11.0.10707000
configured using `configure  '--prefix=/local/net/arch/linux_x86_64/encap/emacs-23.2''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: no_NO.UTF-8
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<down-mouse-1> <mouse-1> C-x C-b e C-x m q <tab> <M-backspace> 
C-x k <return> y e s <return> C-x C-g M-x r e c <backspace> 
p o <tab> r t <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Commands: d, s, x, u; f, o, 1, 2, m, v; ~, %; q to quit; ? for help.
Making completion list...

Load-path shadows:
/home/o/obh/emacs/cperl-mode hides /local/net/arch/linux_x86_64/encap/emacs-23.2/share/emacs/23.2/lisp/progmodes/cperl-mode

Features:
(shadow sort mail-extr emacsbug help-mode view message sendmail
regexp-opt ecomplete rfc822 mml easymenu mml-sec password-cache
mm-decode mm-bodies mm-encode mailcap mail-parse rfc2231 rfc2047
rfc2045 qp ietf-drums mailabbrev nnheader gnus-util netrc time-date
mm-util mail-prsvr gmm-utils wid-edit mailheader canlock sha1 hex-util
hashcash mail-utils warnings server compile comint ring tooltip
ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd font-setting
tool-bar dnd fontset image fringe lisp-mode register page menu-bar
rfn-eshadow timer select scroll-bar mldrag 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 loaddefs button
minibuffer faces cus-face files text-properties overlay md5 base64
format env code-pages mule custom widget hashtable-print-readable
backquote make-network-process font-render-setting gtk x-toolkit x
multi-tty emacs)

bug#8248: 23.2; Emacs 23.2 very slow over ssh when vertical-scroll-bar is enabled

[Stefan Monnier]

> When vertical-scroll-bar is enabled on emacs 23.2 and used over ssh -X
> then switching buffers (^X ^B) takes several seconds. Likewise
> scrolling, changing windows etc. is very sluggish. I have a 12/5 Mbps
> cable line between work/home with usually 8-12ms ICMP rtt. Plenty of
> available bandwidth and CPU.

This will depend on the kind of vertical scollbars you're using.
The bug-data you sent indicates you're using a Gtk build, so it may also
depend on the theme you're using.

Do you see similar problems when running other Gtk applications over
this "ssh -X" tunnel?

> When googling 'emacs ssh latency' there seems to be more people
> having this problem and the prevalent advise was to use use server
> fonts and not client fonts. I tried to compile emacs with

I have no first hand knowledge of how server-side fonts compare to
client-side fonts, but according the some influential X11 hacker,
client-side fonts may actually be better because the bandwidth required
to send the chars's bitmaps is not significantly higher than the font
metrics that the client otherwise has to download from the server, but
sending the bitmaps can be streamed and is latency tolerant whereas
requesting the font metric tends to suffer from a lot of
round-tripping.


        Stefan

bug#8248: 23.2; Emacs 23.2 very slow over ssh when vertical-scroll-bar is enabled

[Stefan Kangas]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> When vertical-scroll-bar is enabled on emacs 23.2 and used over ssh -X
>> then switching buffers (^X ^B) takes several seconds. Likewise
>> scrolling, changing windows etc. is very sluggish. I have a 12/5 Mbps
>> cable line between work/home with usually 8-12ms ICMP rtt. Plenty of
>> available bandwidth and CPU.
>
> This will depend on the kind of vertical scollbars you're using.
> The bug-data you sent indicates you're using a Gtk build, so it may also
> depend on the theme you're using.
>
> Do you see similar problems when running other Gtk applications over
> this "ssh -X" tunnel?

More information was requested, but none was given within 9 years, so
I'm closing this bug.  If this is still an issue, please reply to this
email (use "Reply to all" in your email client) and we can reopen the
bug report.

Best regards,
Stefan Kangas