Subject: bug#2184: 23.0.60; performance issue since CVS 2009-01-30

From: poppyer <[email-masked]>
Date: Wed, 04 Feb 2009 21:53:25 +0800

Adrian Robert <[email-masked]> writes:

> I have not noticed performance problems here but there have been
> significant changes from 01/28 through today 02/04 and it is possible
> there are problems under some usage conditions.  First, could you
> test again using current CVS (including 02/04 changes)?  Also, is
> there an easy way to obtain the 100% CPU usage cases in a mode that
> comes with emacs?  What OS X version are you on?

Yes, today 02-04 is the same, and I am using OSX 10.5.6.

I am sorry but I am unable to reproduce it in other simple setup.

However, we seem to trace down that the issue is about regular
expression matching, as also mention in:
http://lists.gnu.org/archive/html/emacs-devel/2009-02/msg00012.html, 
there are some clue about function "re-search-forward"

I profile in my w3m case, with exactly the same procedure here comes:

Function Name                                      Call Count Elapsed Time Average Time
====================== with 2009-02-04 Emacs executable =======================
regexp-opt-group                                    2668        2.5593199999  0.0009592653
re-search-forward                                   730         1.4294740000  0.0019581835
run-hooks                                           38          1.3881749999  0.0365309210
regexp-opt                                          162         0.8015100000  0.0049475925
regexp-quote                                        1650        0.0171659999  1.040...e-05
remove-text-properties                              506         0.0074000000  1.462...e-05
====================== with 2009-01-19 Emacs executable =======================
regexp-opt-group                                    2668        0.4568619999  0.0001712376
regexp-opt                                          162         0.1268280000  0.0007828888
re-search-forward                                   730         0.0308000000  4.219...e-05
run-hooks                                           37          0.029099      0.0007864594
run-at-time                                         41          0.0009150000  2.231...e-05
regexp-quote                                        1650        0.0008870000  5.375...e-07
remove-text-properties                              506         0.0007210000  1.424...e-06

Is there any specific changes in regular expression part in 2009-01-30
(not about lisp but the Emacs executable)?

> thanks.