bug#2912: 23.0.92; Ediff over TRAMP too slow

[David Abrahams]

Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your bug report will be posted to the emacs-pretest-bug@gnu.org mailing list.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

Ediff two remote files using /ssh:... protocol

It seems to go over the network for everything.  At first I thought it
was the auto-refining, but I turned that off and it didn't seem to make
any difference in speed.

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'.
If you would like to further debug the crash, please read the file
/Applications/Emacs.app/Contents/Resources/etc/DEBUG for instructions.


In GNU Emacs 23.0.92.1 (i386-apple-darwin9.6.0, NS apple-appkit-949.43)
 of 2009-04-06 on black.local
Windowing system distributor `Apple', version 10.3.949
configured using `configure  '--with-ns''

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: nil
  value of $XMODIFIERS: nil
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Major mode: BSDmakefile

Minor modes in effect:
  diff-auto-refine-mode: t
  shell-dirtrack-mode: t
  show-paren-mode: t
  server-mode: t
  global-auto-revert-mode: t
  delete-selection-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
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
- r e v i <tab> <return> <return> <return> C-b C-e 
<return> SPC SPC SPC SPC SPC SPC C-x C-n C-x C-f <M-backspace> 
<M-backspace> <M-backspace> <backspace> <return> C-n 
C-p C-. C-. C-. C-, C-b C-SPC C-e M-w C-x C-f C-a C-. 
C-. C-, C-. C-SPC C-e p r o . c o m : . d o v e c o 
t . s i e <tab> <return> C-n C-n C-n C-n C-p C-p C-p 
C-p C-s a m a z o n C-, C-, C-, C-, C-, C-, C-, C-n 
C-n C-e C-, C-, C-, C-, C-, C-. C-. C-. C-, C-, C-, 
C-, C-, C-p C-p C-n C-n C-n C-, C-, C-, C-, C-, C-. 
C-e C-, C-, C-, C-, C-, C-p C-x C-f . d o <tab> s i 
<tab> . <tab> C-g C-n C-n C-p C-p <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> C-, 
C-, C-, C-, C-, C-b C-s C-w C-s C-s C-r C-n C-p C-p 
C-n C-r C-r C-r C-r C-r C-. C-. C-, C-b C-SPC C-, C-b 
<backspace> C-n C-n C-n C-n C-n C-n C-p C-. C-. C-. 
C-, C-b <M-backspace> <backspace> C-n C-n C-n C-n C-. 
C-. C-, C-b <M-backspace> <backspace> C-x C-s C-x C-n 
C-x C-n C-x C-p C-x C-p C-x C-k C-x C-n C-n C-n C-p 
C-p C-x C-n C-x C-g C-x C-g C-x C-b C-x C-b C-x C-p 
C-x C-b C-x C-b C-x C-b C-n C-n C-n C-n C-x b * E d 
i <tab> C <tab> <return> | | <M-S-down> <M-S-down> 
C-g C-g C-a C-n SPC C-a C-e C-a C-e C-n C-b C-b C-b 
C-b C-b SPC p p ? @ p ? C-n C-p C-n C-, C-, C-, C-, 
C-. C-. C-, q y M-x r e p o r t e <backspace> - e m 
<tab> <return>

Recent messages:
Mark saved where search started [2 times]
Mark set
Saving file /ssh:boostpro.com:/home/dave/.dovecot.sieve...
Wrote /ssh:boostpro.com:/home/dave/.dovecot.sieve
Entering debugger...
Quit [2 times]
ediff-next-difference: At end of the difference list
Auto-refining is OFF
Region 4 in buffer A is empty [2 times]
Quit this Ediff session? (y or n) 

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com