X.org idle for ~6 seconds on startup

[Lorenzo Colitti <lorenzo colitti com>]

Hi,

as part of my work in looking at gnome login times I instrumented the 
whole process of loading gnome from gdm starting from when gdm starts up:

http://www.gnome.org/~lcolitti/gnome-startup/bootcharts/instrument-gdm.png

One thing I don't understand is why the XOpenDisplay() call from gdm 
takes so long (11 seconds!). Granted, for the first 5-6 seconds the X 
server is pegging the CPU, but after that the system seems mostly idle 
for about 6 seconds.

gdm is completely idle during that time (it's sleeping in a select() if 
I remember right). I have tried stracing the X server and it seems that 
some of it is waiting for the font server, which I'm not running. But 
even after I took commented out FontPath "unix/:7100" from xorg.conf 
there are still 3-4 seconds in which the system is mostly idle that I 
cannot account for.

Any ideas?


Cheers,
Lorenzo