[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: reducing equality tests in displaying text
From: |
Kenichi Handa |
Subject: |
Re: reducing equality tests in displaying text |
Date: |
Wed, 28 Jan 2009 16:03:01 +0900 |
In article <address@hidden>, YAMAMOTO Mitsuharu <address@hidden> writes:
>>>>>> On Tue, 27 Jan 2009 14:26:42 +0900, Kenichi Handa <address@hidden> said:
>>> 1. Each call of assoc_no_quit (charset,_encoding_charset_alist) in
>>> fontset.c can be replaced with assq_no_quit because
>>> Vfont_encoding_charset_alist is a symbol-keyed alist.
> > Yes, just fixed.
> There's another occurrence in font_for_char.
Oops, just fixed.
> > When font_group is Qnil, in most cases, SUB_CHAR_TABLE_P (table) is
> > zero. Thus the calculation of FROM and TO must not be that slow.
> > Did you really see the bottle-neck of the performance here?
> Below is a part of the result of an experiment (after your change)
> with Shark.app on Mac OS X 10.5.6. I scrolled up and down the Japanese
> tutorial. Emacs is compiled with Xft support and the default CFLAGS
> (-g -O2 -Wno-pointer-sign).
> 957.8 ms emacs mark_object
> 194.3 ms emacs mark_vectorlike
> 147.9 ms emacs Fgarbage_collect
> 145.3 ms libfreetype.6.dylib tt_cmap4_char_map_binary
> 108.9 ms emacs char_table_ref_and_range
> 98.8 ms emacs sub_char_table_ref_and_range
Are you sure that those calls mostly return nil? Could you
please check if this patch surely improve the performance?
*** fontset.c.~1.154.~ 2009-01-28 15:14:18.000000000 +0900
--- fontset.c 2009-01-28 15:50:37.000000000 +0900
***************
*** 470,476 ****
return font_group;
base_fontset = FONTSET_BASE (fontset);
if (c >= 0)
! font_group = char_table_ref_and_range (base_fontset, c, &from, &to);
else
font_group = FONTSET_FALLBACK (base_fontset);
if (NILP (font_group))
--- 470,480 ----
return font_group;
base_fontset = FONTSET_BASE (fontset);
if (c >= 0)
! {
! font_group = char_table_ref (base_fontset, c);
! if (! NILP (font_group))
! font_group = char_table_ref_and_range (base_fontset, c, &from, &to);
! }
else
font_group = FONTSET_FALLBACK (base_fontset);
if (NILP (font_group))
>>> 3. Despite its argument name, `has_char' functions in font backend
>>> drivers are mostly called for a font object instead of a font
>>> entity. Some font backend drivers could make use of this fact:
>>> e.g., ftfont_has_char can avoid frequent assoc_no_quit calls if
>>> struct ft_font has a reference to fc_charset in ft_face_cache.
> > I've just fixed ftfont_has_char to use FT_Get_Char_Index directly.
> But FT_Get_Char_Index is much slower than FcCharSetHasChar.
> `tt_cmap4_char_map_binary' in the above table is called from
> FT_Get_Char_Index.
Hmmm. I've just found that Xft has the function
XftCharExists now. I remember that it didn't exist in a
rather old vesion. Does your Xft library have this
function?
---
Kenichi Handa
address@hidden
- reducing equality tests in displaying text, YAMAMOTO Mitsuharu, 2009/01/22
- Re: reducing equality tests in displaying text, Kenichi Handa, 2009/01/27
- Re: reducing equality tests in displaying text, YAMAMOTO Mitsuharu, 2009/01/27
- Re: reducing equality tests in displaying text,
Kenichi Handa <=
- Re: reducing equality tests in displaying text, YAMAMOTO Mitsuharu, 2009/01/28
- Re: reducing equality tests in displaying text, Kenichi Handa, 2009/01/28
- Re: reducing equality tests in displaying text, YAMAMOTO Mitsuharu, 2009/01/28
- Re: reducing equality tests in displaying text, Kenichi Handa, 2009/01/28
- Re: reducing equality tests in displaying text, Jason Rumney, 2009/01/28
- Re: reducing equality tests in displaying text, Kenichi Handa, 2009/01/28