very common kernel modules slow down the boot process

Harald Hoyer harald at redhat.com
Wed Apr 2 07:15:24 UTC 2008


Harald Hoyer wrote:
> 39 seconds normal boot time on my system with modprobe of all modules.
> 
> Now a measurement without modprobe:
> 
> # mkinitrd -f  $(/sbin/lsmod |while read a b; do echo --preload 
> $a;done|fgrep -v Module) /boot/initrd-$(uname -r).img $(uname -r)
> 
> initrd now loads all used modules and we can disable modprobe:
> 
> # mv /etc/udev/rules.d/80-drivers.rules 
> /etc/udev/rules.d/80-drivers.rules.bak
> 
> Now the boot time is 36 seconds.
> 
> So, you can shave off a maximum of 3s with modprobe optimization on my 
> system. Also a "small" performance boost.
> 

Also very interesting: if I turn on modprobe again, it takes 38 seconds.
So 2 seconds for already loaded / non existent modules.




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