[Fontconfig] Re: severe performance regression when global fonts.cache-2 files are missing

[Mike FABIAN]

Patrick Lam <plam at MIT.EDU> さんは書きました:

> Mike FABIAN wrote:
>> Tested with a CVS snapshot of the fontconfig 2.4 branch from
>> yesterday.
>> 
>> I noticed that if the global fonts.cache-2 files are out of date,
>> applications using fontconfig take a long time to start.
>> 
>> I understand that this happens once because the user cache file
>> ~/.fonts.cache-2 has to be generated. But if this file has been
>> generated, subsequently called applications should start fast.
>
> I've experienced problems like this before but I can't reliably
> reproduce it on my system right now.  Can you see if it happens if you
> erase your ~/.fonts.cache-2 and start again from scratch?

After erasing ~/.fonts.cache-2, the problem was gone:

mfabian at magellan:~$ time fc-list "Luxi Sans" ; ls -l --time-style=full-iso .fonts.cache-2
Luxi Sans:style=Bold
Luxi Sans:style=Regular
Luxi Sans:style=Oblique
Luxi Sans:style=Bold Oblique

real	2m17.041s
user	0m50.395s
sys	0m2.880s
-rw-------  1 mfabian suse 4555986 2005-10-20 23:43:55.000000000 +0200 .fonts.cache-2
mfabian at magellan:~$ time fc-list "Luxi Sans" ; ls -l --time-style=full-iso .fonts.cache-2
Luxi Sans:style=Bold
Luxi Sans:style=Regular
Luxi Sans:style=Oblique
Luxi Sans:style=Bold Oblique

real	0m4.089s
user	0m1.096s
sys	0m0.168s
-rw-------  1 mfabian suse 4555986 2005-10-20 23:43:55.000000000 +0200 .fonts.cache-2
mfabian at magellan:~$ time fc-list "Luxi Sans" ; ls -l --time-style=full-iso .fonts.cache-2
Luxi Sans:style=Bold
Luxi Sans:style=Regular
Luxi Sans:style=Oblique
Luxi Sans:style=Bold Oblique

real	0m1.519s
user	0m1.108s
sys	0m0.128s
-rw-------  1 mfabian suse 4555986 2005-10-20 23:43:55.000000000 +0200 .fonts.cache-2
mfabian at magellan:~$ time fc-list "Luxi Sans" ; ls -l --time-style=full-iso .fonts.cache-2
Luxi Sans:style=Bold
Luxi Sans:style=Regular
Luxi Sans:style=Oblique
Luxi Sans:style=Bold Oblique

real	0m1.284s
user	0m1.140s
sys	0m0.108s
-rw-------  1 mfabian suse 4555986 2005-10-20 23:43:55.000000000 +0200 .fonts.cache-2
mfabian at magellan:~$

This is very strange, certainly there is a bug but it appears to be
not easy to reproduce.

-- 
Mike FABIAN   <mfabian at suse.de>   http://www.suse.de/~mfabian
睡眠不足はいい仕事の敵だ。