Re: Performance issue with pango ?

[Owen Taylor <otaylor redhat com>]

"jagadeesh banavara " <jagadeesh bana wipro com> writes:

> Hi,
> 
> "Please 'group reply' to this mail as I am not yet 
> subscribed to this mailing list"
> 
> I am working on performance issues of gnome 'login'.
> 
> >From my basic experiments :
> During splash screen creation, a gnome canvas is
> created. As part of this, the pango call 
> pango_layout_get_pixel_size() seems to be taking lot
> of time. In fact, about 70% of the splash screen creation
> time is consumed by this pango call.
> 
> Anybody has thoughts about how to improve performance
> of this pango call ?

The splash screen doesn't have very much text on it...

I think what you are seeing is not slowness in measuring
text, but slowness initializing the font system.

In fact, what you are seeing isn't just the overhead
of initialign the font system, but the overhead of
initializing the font system for the _first_ app on
the display; the X font backend for Pango caches 
information about font coverage for the display.

This is something specific to the Pango-X backend, and
really can't be improved much other than switching
to better font technology. 

Regards,
                                        Owen

[
 It's possible that you are instead seeing startup
 time problems for the FT2 backend; if this is
 the problem, the solution is to switch to
 FreeType-2.0.9 or better. fontconfig and Pango-1.2
 will improve the FT2 startup times even more.
]