bug#3441: 23.0.94; *compilation* long lines painfully slow

bug#3441: 23.0.94; *compilation* long lines painfully slow

[Marshall, Simon]

Guys, this is a follow-up to
http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=2223.  It
might not have anything to do with that bug at all - I was just going
back and seeing if that bug had been fixed.

Create a Makefile with the contents:

all:
	@echo [insert 5000 chars]

Run emacs -Q and do Tools > Compile... RET and I see Emacs create the
*compilation* window and insert chunks of the echo output.  23.0.94
takes 20+ seconds to complete it and is pretty much unusable during that
time.  22.3 takes 1 second.  Looking back at earlier pretests, this also
applies to 23.0.91.

Thanks, Simon.

In GNU Emacs 23.0.94.1 (sparc-sun-solaris2.8, Motif Version 2.1.0)
 of 2009-06-01 on risksun2
Windowing system distributor `Hummingbird Ltd.', version 11.0.100015
configured using `configure
'--x-includes=/usr/openwin/include:/usr/dt/include:/usr/local/include:/u
sr/local/X11/include'
'--x-libraries=/usr/openwin/lib:/usr/dt/lib:/usr/local/lib:/usr/local/X1
1/lib' '--with-x-toolkit=motif' '--with-jpeg=no' '--with-gif=no'
'--with-tiff=no' 'CFLAGS=-g''

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

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-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


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bug#3441: 23.0.94; *compilation* long lines painfully slow

[Chong Yidong]

> Create a Makefile with the contents:
>
> all:
> 	@echo [insert 5000 chars]
>
> Run emacs -Q and do Tools > Compile... RET and I see Emacs create the
> *compilation* window and insert chunks of the echo output.  23.0.94
> takes 20+ seconds to complete it and is pretty much unusable during that
> time.  22.3 takes 1 second.  Looking back at earlier pretests, this also
> applies to 23.0.91.

This is due to the following in compilation-error-regexp-alist-alist:

  (maven
   ;; Maven is a popular build tool for Java.  Maven is Free Software.
   "\\(.*?\\):\\[\\([0-9]+\\),\\([0-9]+\\)\\]" 1 2 3)

which was added here:

2007-07-25  Joakim Verona  <joakim@verona.se>  (tiny change)

	* progmodes/compile.el (compilation-error-regexp-alist-alist):
	Add support for the Maden build tool.

This regexp is pathologically slow on long lines.  Since the performance
impact is quite serious, and this bug has affected more than one user, I
went ahead and commented out this line in compile.el.

Joakim, could try to come up with a faster regexp?

bug#3441: 23.0.94; *compilation* long lines painfully slow

[joakim]

Chong Yidong <cyd@stupidchicken.com> writes:

>> Create a Makefile with the contents:
>>
>> all:
>> 	@echo [insert 5000 chars]
>>
>> Run emacs -Q and do Tools > Compile... RET and I see Emacs create the
>> *compilation* window and insert chunks of the echo output.  23.0.94
>> takes 20+ seconds to complete it and is pretty much unusable during that
>> time.  22.3 takes 1 second.  Looking back at earlier pretests, this also
>> applies to 23.0.91.
>
> This is due to the following in compilation-error-regexp-alist-alist:
>
>   (maven
>    ;; Maven is a popular build tool for Java.  Maven is Free Software.
>    "\\(.*?\\):\\[\\([0-9]+\\),\\([0-9]+\\)\\]" 1 2 3)
>
> which was added here:
>
> 2007-07-25  Joakim Verona  <joakim@verona.se>  (tiny change)
>
> 	* progmodes/compile.el (compilation-error-regexp-alist-alist):
> 	Add support for the Maden build tool.
>
> This regexp is pathologically slow on long lines.  Since the performance
> impact is quite serious, and this bug has affected more than one user, I
> went ahead and commented out this line in compile.el.
>
> Joakim, could try to come up with a faster regexp?

Ok, I will give it a shot.

-- 
Joakim Verona