bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Eli Zaretskii]

> Date: Mon, 26 Sep 2011 22:50:25 -0400
> From: Steve Revilak <steve@srevilak.net>
> 
> I'd like to report an org-mode regression issue.  When working with
> large .org files, Emacs 24.0.90 becomes sluggish, and consumes large
> amounts of CPU.

If you type this:

  M-x set-variable RET bidi-paragraph-direction RET left-to-right RET

does the problem go away?

Org mode should do that by default, but the Org mode maintainer
(CC'ed) didn't yet respond to my repeated mails about this issue.

Bastien, please tell me whether you want me to make this change in the
Emacs repository, or wait for you to do it in the Org mode repo and
then merge to Emacs.

bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Bastien]

Eli Zaretskii <eliz@gnu.org> writes:

> Bastien, please tell me whether you want me to make this change in the
> Emacs repository, or wait for you to do it in the Org mode repo and
> then merge to Emacs.

Please make this change in the Emacs repository.

Thanks,

-- 
 Bastien

bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Steve Revilak]

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>> I'd like to report an org-mode regression issue.  When working with
>> large .org files, Emacs 24.0.90 becomes sluggish, and consumes large
>> amounts of CPU.

>If you type this:
>
>  M-x set-variable RET bidi-paragraph-direction RET left-to-right RET
>
>does the problem go away?

My bug report contained two scenarios to produce sluggish response and
high CPU utilization.  These scenarios were

  (1) move point to the end of buffer, and start typing

  (2) Put point in line 1, column zero; press and hold the down (then up)
  arrows to move point down (then up) the org-mode buffer.

Setting bidi-paragraph-direction: left-to-right eliminates the problem
with scenario (1).  However, it has no effect on scenario (2).

Steve

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bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Eli Zaretskii]

> Date: Tue, 27 Sep 2011 09:47:45 -0400
> From: Steve Revilak <steve@srevilak.net>
> Cc: 9610@debbugs.gnu.org, Bastien Guerry <bzg@gnu.org>, steve@srevilak.net
> 
> My bug report contained two scenarios to produce sluggish response and
> high CPU utilization.  These scenarios were
> 
>   (1) move point to the end of buffer, and start typing
> 
>   (2) Put point in line 1, column zero; press and hold the down (then up)
>   arrows to move point down (then up) the org-mode buffer.

Sorry, I missed the second one.

> Setting bidi-paragraph-direction: left-to-right eliminates the problem
> with scenario (1).  However, it has no effect on scenario (2).

Yes, there was another reason for the slowdown.  I found an
optimization of the new display that solves the problem for me with
your sample Org file.  The fix is committed as revision 105941 on the
trunk.  If you cannot or don't want to build the trunk, the patch is
reproduced below; please try it.  On my machine, the cursor motion is
now as fast as in Emacs 23 with the same file.

I'm closing the bug.  Feel free to reopen if there are any leftovers.

Thanks.

=== modified file 'src/ChangeLog'
--- src/ChangeLog	2011-09-27 08:37:07 +0000
+++ src/ChangeLog	2011-09-27 17:18:31 +0000
@@ -1,3 +1,11 @@
+2011-09-27  Eli Zaretskii  <eliz@gnu.org>
+
+	* xdisp.c (handle_invisible_prop): If invisible text ends on a
+	newline, reseat the iterator instead of bidi-iterating there one
+	character at a time.  (Bug#9610)
+	(BUFFER_POS_REACHED_P, move_it_in_display_line_to): Bail when past
+	TO_CHARPOS if the bidi iterator is at base embedding level.
+
 2011-09-27  Andreas Schwab  <schwab@linux-m68k.org>
 
 	* lread.c (readevalloop): Use correct code for NBSP.

=== modified file 'src/xdisp.c'
--- src/xdisp.c	2011-09-24 16:28:25 +0000
+++ src/xdisp.c	2011-09-27 17:18:31 +0000
@@ -4056,40 +4056,67 @@ handle_invisible_prop (struct it *it)
 	  /* The position newpos is now either ZV or on visible text.  */
 	  if (it->bidi_p && newpos < ZV)
 	    {
-	      /* With bidi iteration, the region of invisible text
-		 could start and/or end in the middle of a non-base
-		 embedding level.  Therefore, we need to skip
-		 invisible text using the bidi iterator, starting at
-		 IT's current position, until we find ourselves
-		 outside the invisible text.  Skipping invisible text
-		 _after_ bidi iteration avoids affecting the visual
-		 order of the displayed text when invisible properties
-		 are added or removed.  */
-	      if (it->bidi_it.first_elt && it->bidi_it.charpos < ZV)
-		{
-		  /* If we were `reseat'ed to a new paragraph,
-		     determine the paragraph base direction.  We need
-		     to do it now because next_element_from_buffer may
-		     not have a chance to do it, if we are going to
-		     skip any text at the beginning, which resets the
-		     FIRST_ELT flag.  */
-		  bidi_paragraph_init (it->paragraph_embedding,
-				       &it->bidi_it, 1);
-		}
-	      do
+	      EMACS_INT bpos = CHAR_TO_BYTE (newpos);
+
+	      if (FETCH_BYTE (bpos) == '\n'
+		  || (newpos > BEGV && FETCH_BYTE (bpos - 1) == '\n'))
 		{
-		  bidi_move_to_visually_next (&it->bidi_it);
+		  /* If the invisible text ends on a newline or the
+		     character after a newline, we can avoid the
+		     costly, character by character, bidi iteration to
+		     newpos, and instead simply reseat the iterator
+		     there.  That's because all bidi reordering
+		     information is tossed at the newline.  This is a
+		     big win for modes that hide complete lines, like
+		     Outline, Org, etc.  (Implementation note: the
+		     call to reseat_1 is necessary, because it signals
+		     to the bidi iterator that it needs to reinit its
+		     internal information when the next element for
+		     display is requested.  */
+		  struct text_pos tpos;
+
+		  SET_TEXT_POS (tpos, newpos, bpos);
+		  reseat_1 (it, tpos, 0);
+		}
+	      else	/* Must use the slow method.  */
+		{
+		  /* With bidi iteration, the region of invisible text
+		     could start and/or end in the middle of a
+		     non-base embedding level.  Therefore, we need to
+		     skip invisible text using the bidi iterator,
+		     starting at IT's current position, until we find
+		     ourselves outside the invisible text.  Skipping
+		     invisible text _after_ bidi iteration avoids
+		     affecting the visual order of the displayed text
+		     when invisible properties are added or
+		     removed.  */
+		  if (it->bidi_it.first_elt && it->bidi_it.charpos < ZV)
+		    {
+		      /* If we were `reseat'ed to a new paragraph,
+			 determine the paragraph base direction.  We
+			 need to do it now because
+			 next_element_from_buffer may not have a
+			 chance to do it, if we are going to skip any
+			 text at the beginning, which resets the
+			 FIRST_ELT flag.  */
+		      bidi_paragraph_init (it->paragraph_embedding,
+					   &it->bidi_it, 1);
+		    }
+		  do
+		    {
+		      bidi_move_to_visually_next (&it->bidi_it);
+		    }
+		  while (it->stop_charpos <= it->bidi_it.charpos
+			 && it->bidi_it.charpos < newpos);
+		  IT_CHARPOS (*it) = it->bidi_it.charpos;
+		  IT_BYTEPOS (*it) = it->bidi_it.bytepos;
+		  /* If we overstepped NEWPOS, record its position in
+		     the iterator, so that we skip invisible text if
+		     later the bidi iteration lands us in the
+		     invisible region again. */
+		  if (IT_CHARPOS (*it) >= newpos)
+		    it->prev_stop = newpos;
 		}
-	      while (it->stop_charpos <= it->bidi_it.charpos
-		     && it->bidi_it.charpos < newpos);
-	      IT_CHARPOS (*it) = it->bidi_it.charpos;
-	      IT_BYTEPOS (*it) = it->bidi_it.bytepos;
-	      /* If we overstepped NEWPOS, record its position in the
-		 iterator, so that we skip invisible text if later the
-		 bidi iteration lands us in the invisible region
-		 again. */
-	      if (IT_CHARPOS (*it) >= newpos)
-		it->prev_stop = newpos;
 	    }
 	  else
 	    {
@@ -7880,7 +7907,9 @@ move_it_in_display_line_to (struct it *i
   ((op & MOVE_TO_POS) != 0					\
    && BUFFERP (it->object)					\
    && (IT_CHARPOS (*it) == to_charpos				\
-       || (!it->bidi_p && IT_CHARPOS (*it) > to_charpos)	\
+       || ((!it->bidi_p						\
+	    || BIDI_AT_BASE_LEVEL (it->bidi_it))		\
+	   && IT_CHARPOS (*it) > to_charpos)			\
        || (it->what == IT_COMPOSITION				\
 	   && ((IT_CHARPOS (*it) > to_charpos			\
 		&& to_charpos >= it->cmp_it.charpos)		\
@@ -7912,7 +7941,13 @@ move_it_in_display_line_to (struct it *i
       if ((op & MOVE_TO_POS) != 0
 	  && BUFFERP (it->object)
 	  && it->method == GET_FROM_BUFFER
-	  && ((!it->bidi_p && IT_CHARPOS (*it) > to_charpos)
+	  && (((!it->bidi_p
+		/* When the iterator is at base embedding level, we
+		   are guaranteed that characters are delivered for
+		   display in strictly increasing order of their
+		   buffer positions.  */
+		|| BIDI_AT_BASE_LEVEL (it->bidi_it))
+	       && IT_CHARPOS (*it) > to_charpos)
 	      || (it->bidi_p
 		  && (prev_method == GET_FROM_IMAGE
 		      || prev_method == GET_FROM_STRETCH

bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Lawrence Mitchell]

Steve Revilak wrote:

>>> I'd like to report an org-mode regression issue.  When working with
>>> large .org files, Emacs 24.0.90 becomes sluggish, and consumes large
>>> amounts of CPU.

>> If you type this:

>>  M-x set-variable RET bidi-paragraph-direction RET left-to-right RET

>> does the problem go away?

> My bug report contained two scenarios to produce sluggish response and
> high CPU utilization.  These scenarios were

>  (1) move point to the end of buffer, and start typing

>  (2) Put point in line 1, column zero; press and hold the down (then up)
>  arrows to move point down (then up) the org-mode buffer.

> Setting bidi-paragraph-direction: left-to-right eliminates the problem
> with scenario (1).  However, it has no effect on scenario (2).

Setting bidi-display-reordering to nil in the buffer has the
effect that moving point is no longer jerky for me.

Lawrence

bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Eli Zaretskii]

> From: Lawrence Mitchell <wence@gmx.li>
> Date: Tue, 27 Sep 2011 16:10:25 +0100
> 
> Setting bidi-display-reordering to nil in the buffer has the
> effect that moving point is no longer jerky for me.

I think with the latest trunk, you won't need to fiddle with this
variable anymore.

Re: bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Eric S Fraga]

Lawrence Mitchell <wence@gmx.li> writes:

> Steve Revilak wrote:
>
>>>> I'd like to report an org-mode regression issue.  When working with
>>>> large .org files, Emacs 24.0.90 becomes sluggish, and consumes large
>>>> amounts of CPU.
>
>>> If you type this:
>
>>>  M-x set-variable RET bidi-paragraph-direction RET left-to-right RET
>
>>> does the problem go away?
>
>> My bug report contained two scenarios to produce sluggish response and
>> high CPU utilization.  These scenarios were
>
>>  (1) move point to the end of buffer, and start typing
>
>>  (2) Put point in line 1, column zero; press and hold the down (then up)
>>  arrows to move point down (then up) the org-mode buffer.
>
>> Setting bidi-paragraph-direction: left-to-right eliminates the problem
>> with scenario (1).  However, it has no effect on scenario (2).
>
> Setting bidi-display-reordering to nil in the buffer has the
> effect that moving point is no longer jerky for me.

Brilliant!  I have been getting rather annoyed at the jerky movement in
a number of buffers, mostly org, but I knew the problem wasn't due to
org having done timings etc.  Setting this to nil does the job.

What do you recommend is the best way to handle this: in org-mode-hook
for instance?

thanks,
eric

-- 
: Eric S Fraga (GnuPG: 0xC89193D8FFFCF67D) in Emacs 24.0.50.1
: using Org-mode version 7.7 (release_7.7.328.g1a97)

Re: bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Tom Davey]

On Tue, Sep 27, 2011 at 3:11 PM, Eric S Fraga <e.fraga@ucl.ac.uk> wrote:

> Brilliant!  I have been getting rather annoyed at the jerky movement in
> a number of buffers, mostly org, but I knew the problem wasn't due to
> org having done timings etc.  Setting this to nil does the job.

Yes, a very bothersome issue. Large org files were nearly unusable;
Windows reported that Emacs was using up to 25% of the CPU when I was
simply typing text. I wasted half a day today trying to track this
issue down, until I remembered this thread on the list earlier this
week. Setting this obscure variable to nil in org-mode-hook does the
trick. Thanks so much.

--
Tom Davey
tom@tomdavey.com
New York NY USA

bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Eli Zaretskii]

> From: Bastien <bzg@altern.org>
> Cc: Steve Revilak <steve@srevilak.net>,  9610@debbugs.gnu.org
> Date: Tue, 27 Sep 2011 08:02:47 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Bastien, please tell me whether you want me to make this change in the
> > Emacs repository, or wait for you to do it in the Org mode repo and
> > then merge to Emacs.
> 
> Please make this change in the Emacs repository.

Done in revision 105940.

bug#9610: 24.0.90; org-mode: sluggish response and high CPU utilization with large .org files

[Bastien]

Eli Zaretskii <eliz@gnu.org> writes:

>> Please make this change in the Emacs repository.
>
> Done in revision 105940.

Thanks!  I added your change to Org's git repo:

http://orgmode.org/w/?p=org-mode.git;a=commit;h=1a97f29c342d85960a65c0bd992fee7c87850da5

Best,

-- 
 Bastien