Ubuntu 11.04 boot time is 80 seconds 67 of which belong to the udevd process. Here's what dmesg shows:
[ 6.534288] EXT4-fs (sda5): mounted filesystem with ordered data mode. Opts: (null)
[ 73.216006] udevd[399]: starting version 175
What udevd does and is it possible to reduce the time of its work?
The required device information is exported by the sysfs file system. For every device the kernel has detected and initialized, a directory with the device name is created. It contains attribute files with device-specific properties.
Every time a device is added or removed, the kernel sends a uevent to notify udev of the change. The udev daemon reads and parses all provided rules from the /etc/udev/rules.d/*.rules files once at start-up and keeps them in memory. If rules files are changed, added or removed, the daemon can reload the in-memory representation of all rules with the command udevadm control reload_rules. This is also done when running /etc/init.d/boot.udev reload.
To know how to optimize a boot time please see this pdf file
This also would help you
If you want to check if there is a device stoping udev use this command
udevadm trigger -v
