[Debian-eeepc-devel] Boot time and module-init-tools 3.4 and 3.5

[Santi Béjar]

Hi *,

  I've been testing how the boot time can be improved, this time with
the help module-init-tools 3.5[1] which has some performances changes.
I have not teste with a newer udev because I haven't seen performances
changes since the version in Debian. And here are the results[2]

For the testing kernel (2.6.26-1-686):

module-init-tools [ time ]
3.4          [   22.236454]
3.5          [   16.819960]
3.5 + depmod [   14.813826]

as you can see just upgrading to 3.5 the boot times decrease 5.5
seconds, with 5 additional seconds when using binary dep files
(rerunning depmod).

So in total we gain 7.5 seconds just upgrading to 3.5.

The same with 2.6.28-rc5 (everything builtin, no initrd, + a patch to
no longer need the pciehp):

notes                  [       time ] [ w/o pre-dev]
coldplug               [   16.112153] [   15.963127]
usb and input coldplug [   12.173776]
m-i-t=3.5 coldplug     [   12.883749]
above + depmod         [    9.342581] [    9.190434]

As you can see there is also a big improvement (6.5 seconds) and in
fact a prepopulated /dev (in /lib/dev/devices) is slower than a normal
one.

Also notice that the difference between all modules and all builtin is
about 5 seconds (although it should be test with the same kernel
version...)

HTH,
Santi

[1] I've compiled the 3.5 locally, just with the upstream tarball, +
the debian diff for 3.4-1.

[2] I measure the time until one of the init.d scripts is executed, in
particular avahi because it throws a warning in the dmesg output. Also
notice that this is on top of other performances changes already
explained in other post in this list and the wiki.