Interaction of udev with the init subsystem

["Ozan Çağlayan" <ozan@pardus.org.tr>]

Hi,

I'm maintaining the udev package for Pardus, a GNU/Linux distribution
mainly developed in Turkey.

After doing some investigations of the startup time on our distribution,
I've figured that udev related invocations takes a lot of time.

1) The startup of the daemon is quick enough, no problem here,
2) The first trigger+settle takes ~4.5 seconds to complete.

We're currently using udev-126 but I also tried 137, and the performance
is quite the same.

I wonder what are the points that a distribution packager/maintainer should consider
when starting/stopping udev for having the best startup time.

My second question is about the orphaned rule files left in /dev/.udev
after triggering the event processing on a read-only root filesystem. I'm succesfully
collecting those rules, moving them into /etc/udev/rules.d and recalling trigger
after mounting the root filesystem read-write. If I don't retrigger,
no dvd, cdrw, etc. symlink are created in /dev if the optical drive contains
a media during boot. Retriggering here takes ~0.11 seconds.

It would be very nice to have a detailed documentation for udev beside rule writing stuff.

Thanks,

-- 

Ozan Çağlayan
<ozan_at_pardus.org.tr>