Re: Low memory hacks

[Brian Nitz <Brian Nitz Sun COM>]

Behdad Esfahbod wrote:
> On Fri, 2008-02-29 at 13:32 +0000, Brian Nitz wrote:
>   
> > For example, launching eog in the "C" locale (Solaris Nevada build
> > 82, 
> > GNOME 2.20.2)  opens font files for many other locales.  These may be 
> > mapped into physical memory at times, regardless of your locale. :
> >
> >   4302 eog           18 
> > /usr/openwin/lib/locale/zh/X11/fonts/TrueType//fonts.cache-1
> >   4302 eog           -1 
> > /usr/openwin/lib/locale/zh_CN.GB18030/X11/fonts/75dpi//fonts.cache-1
> >     
> [...]
>   
> > This might make sense for a browser or email client, but if there is
> > a 
> > performance and memory impact, it would be nice to have the option to 
> > disable loading of fonts from other locales.  Some GNOME users are 
> > running on thin client kiosks on isolated networks (banks...) where
> > they 
> > are unlikely to need all of these fonts.
> >     
>
> This makes zero sense.  First, those are caches, not actual fonts.
> Second, they are mapped into the address space readonly, not "read", so
> they don't consume per-process memory.
Good point.  The opens of so many (often unnecessary) font cache files 
during every application launch may impact performance if not memory but 
that's another topic.

>   Third, there's no such thing as
> locale-specific fonts.  If a font happens to cover Chinese only, so be
> it.  Finally, if you don't need those fonts, simply don't install them
> (or uninstall them).  
>   
I know it doesn't make sense from a developer's point of view, but it 
has been a request for end users, "We don't ever use (X language) fonts 
in our  Hospital/Bank/University/Government Office, why are we 
installing these fonts?"  It may be a distribution specific issue, but 
it's probably an issue with nearly every distribution.
> If a font is installed, it HAS to be noted in the
> cache somewhere to be discoverable by apps.
O.K. but opening and mapping these files on every application launch 
even when the associated fonts may _never_ be read for a particular user 
doesn't seem to be the most efficient thing to do.
> Ok, now looking at your list again, you are running an old version of
> fontconfig that does in fact read those caches into memory for each
> process.  Use a newer fontconfig, and that would save you some 100k per
> process, or more.
>   
Thanks for this information.  This will be useful.