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

[Lennart Poettering]

On Tue, 10.05.11 17:34, Koen Kooi (koen at dominion.thruhere.net) wrote:

> 
> 
> Op 10 mei 2011, om 14:14 heeft Lennart Poettering het volgende geschreven:
> 
> > On Tue, 10.05.11 14:11, Harald Hoyer (harald.hoyer at gmail.com) wrote:
> > 
> >> 
> >> Am 10.05.2011 14:09, schrieb Lennart Poettering:
> >>> On Tue, 10.05.11 13:47, Koen Kooi (koen at dominion.thruhere.net) wrote:
> >>> 
> >>>>> What udev version is that? I'm running current -git, maybe something
> >>>>> was broken, don't know it though.
> >>>> 
> >>>> [  122.891967]<27>udevd[88]: unable to receive ctrl connection: Function not implemented
> >>>> 
> >>>> Time to rebuild eglibc I guess.
> >>> 
> >>> Hmm, does your kernel lack AF_UNIX/SOCK_SEQPACKET support?
> >>> 
> >>> Lennart
> >>> 
> >> 
> >> Might be time, for a .config list of required features :-)
> > 
> > Neither accept4 nor AF_UNIX/SOCK_SEQPACKET are optional kernel
> > features. However, they are relatively new kernel features and some
> > archs had trouble keeping up in enabling them even though the code
> > exists in the kernel.
> > 
> > Currently our README mentions that we need kernel >= 2.6.30. It might
> > make sense to include another line mentioning that on ARM/MIPS/others
> > you need an even newer one.
> 
> So after rebuilding eglibc against 2.6.37 headers and udev from git:
> 
> root at beagleboard-systemd:~# time ( udevadm trigger ; udevadm settle )
> 
> real    0m10.475s
> user    0m0.000s
> sys     0m0.133s
> 
> And the matching systemd-analyze plot: http://dominion.thruhere.net/koen/angstrom/systemd/git-with-accept4.svg

Seems the triggering takes a about a second. Which is not particularly
good, but I guess not the most pressing issue.

It seems the devices are probed very slowly, and even the tty devices
take ages to complete. i.e. between most VC tts to showing up almost a
second passes.

Might be useful to run bootchart on this to get a more finegrained idea
what udev is doing there.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.