[systemd-devel] device units rely on udev rules?

[Lennart Poettering]

On Mon, 09.05.11 21:51, Koen Kooi (koen at dominion.thruhere.net) wrote:

> >> This means there are a large number of devices already known to the kernel
> >> at the point that systemd starts, especially if you build the drivers into
> >> the kernel for those devices. It's possible to get going straight away with
> >> those devices. But relying on udevd tagging them means you end up waiting
> >> around for udevd to start, and worse! since udevd doesn't apply rules to
> >> existing devices on startup, you have to wait around for "udevadm trigger"
> >> to be run.
> > 
> > That's actually dead fast
> 
> It's still in the 10 second range on a 600MHz cortex-a8 machine
> booting from an SD card. I need to dig out my 400MHz arm920t to see
> how long it takes there. So having udev-less operation in systemd
> would be nice, even if it's only used on 'embedded'

Have you checked what precisely takes so long? My guess is that some
driver has a slow sysfs uevent trigger callback, and that might be
fixable in the driver. You might want to use strace with timestamps to
figure out why udev trigger might be so slow.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.