GNU bug report logs - #8333
24.0.50; Performace regression from r100619 try_scrolling change

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

From: Chong Yidong <cyd <at> stupidchicken.com>
To: bug-gnu-emacs <at> gnu.org
Cc: Eli Zaretskii <eliz <at> gnu.org>
Subject: 24.0.50; Performace regression from r100619 try_scrolling change
Date: Wed, 23 Mar 2011 17:39:37 -0400

  2010-06-19  Eli Zaretskii  <eliz <at> gnu.org>

  * xdisp.c (try_scrolling): Compute the limit for searching point
  in forward scroll from scroll_max, instead of an arbitrary limit
  of 10 screen lines.  See
  http://lists.gnu.org/archive/html/emacs-devel/2010-06/msg00766.html
  and
  http://lists.gnu.org/archive/html/emacs-devel/2010-06/msg00773.html
  for details.

This change (on trunk) causes a big slowdown in navigating large
buffers.  To reproduce, make a .emacs with just the following line:

(setq scroll-conservatively 1000)

Then:

emacs /path/to/xdisp.c
M-g M-g 20000 RET

Emacs takes about a second to move point to the specified line.  If the
above change is reverted, moving is instantaneous.  The slowdown is much
more apparent if Emacs is compiled without optimizations.


In GNU Emacs 24.0.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.20.1)
 of 2011-03-23 on furball
Windowing system distributor `The X.Org Foundation', version 11.0.10706000
configured using `configure  'CC=gcc' 'CFLAGS=-g''

Message #8 received at 8333 <at> debbugs.gnu.org (full text, mbox):

From: Juanma Barranquero <lekktu <at> gmail.com>
To: Chong Yidong <cyd <at> stupidchicken.com>
Cc: 8333 <at> debbugs.gnu.org
Subject: Re: bug#8333: 24.0.50; Performace regression from r100619
	try_scrolling change
Date: Thu, 24 Mar 2011 00:50:53 +0100

On Wed, Mar 23, 2011 at 22:39, Chong Yidong <cyd <at> stupidchicken.com> wrote:

> This change (on trunk) causes a big slowdown in navigating large
> buffers.  To reproduce, make a .emacs with just the following line:
>
> (setq scroll-conservatively 1000)
>
> Then:
>
> emacs /path/to/xdisp.c
> M-g M-g 20000 RET

Isn't this bug#6671?

    Juanma

Message #11 received at 8333 <at> debbugs.gnu.org (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: Juanma Barranquero <lekktu <at> gmail.com>
Cc: 8333 <at> debbugs.gnu.org
Subject: Re: bug#8333: 24.0.50;
	Performace regression from r100619 try_scrolling change
Date: Wed, 23 Mar 2011 20:01:55 -0400

Juanma Barranquero <lekktu <at> gmail.com> writes:

>> (setq scroll-conservatively 1000)
>>
>> Then:
>>
>> emacs /path/to/xdisp.c
>> M-g M-g 20000 RET
>
> Isn't this bug#6671?

My mistake.  I forgot there was a bug already filed.

Message #16 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Chong Yidong <cyd <at> stupidchicken.com>
Cc: bug-gnu-emacs <at> gnu.org
Subject: Re: 24.0.50; Performace regression from r100619 try_scrolling change
Date: Thu, 24 Mar 2011 06:04:24 +0200

> From: Chong Yidong <cyd <at> stupidchicken.com>
> Cc: Eli Zaretskii <eliz <at> gnu.org>
> Date: Wed, 23 Mar 2011 17:39:37 -0400
> 
>   2010-06-19  Eli Zaretskii  <eliz <at> gnu.org>
> 
>   * xdisp.c (try_scrolling): Compute the limit for searching point
>   in forward scroll from scroll_max, instead of an arbitrary limit
>   of 10 screen lines.  See
>   http://lists.gnu.org/archive/html/emacs-devel/2010-06/msg00766.html
>   and
>   http://lists.gnu.org/archive/html/emacs-devel/2010-06/msg00773.html
>   for details.
> 
> This change (on trunk) causes a big slowdown in navigating large
> buffers.

Yes, this is bug#6671.  It's on my todo.

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