[Debian-eeepc-devel] 13 second boot documentation and why is udev so slow...

[Jelle de Jong]

Hi all,

The new kernel 2.6.30-1-686 came into Debian this last week and I got
the itches to do some fast boot testing. The result is still
disappointing for me, its still the same as a year back and the kernel
even got slower compared to 2.6.29-2-486 but there are some good points.

The parallel booting of script kind of works now. I added my results to
the wiki I hope that's ok:
http://wiki.debian.org/BootProcessSpeedup#Testsresultsofusers

purpose:
I build a lot of different linux systems, some just need fast bootup
like multimedia devices, easy internet devices, netbooks et cetera. one
of the requirements is maintainability and stability. I don't get
maintainability by recompiling my own software, so that is not an
option. What is an option is to tweak all the configuration systems I
can find, test them for stability and use them.

major issues:
the udev process takes an awful lot of time it just stays for more then
7 seconds in the "Waiting for /dev to be fully populated" state probably
caused by udevadm settle. We need to tune udev to become way faster and
keep the solution easy to use and maintainable.

I use grub2 and it has no behavior like hiddenmenu, you can see three
flashes during boot before it comes to the steady "loading system" state.

sometimes my asus eeepc 901 just won't turn off at the last stages of
halt. I got the feeling that some hardware (audio, network) is not
correctly deinitialized and makes the shutdown process hang. SySRq
doesn't react in this stage anymore so the kernel is probably down already.

result:
my boot process is around 13 seconds and 7 á 8 of them are caused by udev.

I hope somebody will pick this up and also improves there systems and
hopefully find some good way to speedup the hole udev stuff with good
maintainable solutions.

Best regards,

Jelle de Jong