# to udev or not to udev?

## Koda

Hello!

I've been tuning the kernel lately and i'm using a module approach, that is, make the kernel as small as possibile and keep what needed as module

however i-ve noticed that udev always loads the module needed at boot time when the device is detected, and this take a good part of the boot process

my question is: is it better to include needed stuff in kernel (marked as *) like agp, e100 etc, or to reduce the kernel size under the 1MB to speed up the boot process?

thanks a lot!

bye

Koda

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## PaulBredbury

 *Koda wrote:*   

> is it better to include needed stuff in kernel (marked as *)

 

Yes. Otherwise, you just make udev do more work at bootup.

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## Koda

thanks for your reply

i noticed that a big kernel takes quite a lot of time to boot so i decided to remain to the modular one

however i noticed that if instead of udev i load the modules manually (i mean in the /etc/modules,autoload/kernel-2.6) the loading process is much faster than udev

is this the right approach?

thanks a lot!

bye

Koda

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## PaulBredbury

If you're compiling the monolithic kernel with just what you need, then the kernel size after udev has loaded the modules should be the same as with your monolithic kernel anyway.

Slow boot, or slow udev loading - make your choice. A "slow boot" is preferable, because udev doesn't have the opportunity to load the wrong modules or miss out modules you wanted/needed, and you can't make a mess of the files in /lib/modules/ if they are already compiled-in.

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## Koda

ok, i'll test both methods to see which suits best, thank you

now i'm testing small kernel + many modules, and i still see that udev is stalling when looking for possible modules to load

since udev populates /dev (correct me if i'm wrong), is it possible to skip the module loading part?

thanks

bye

Koda

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## Koda

i seem to have found a solution

you can disable the slow letting udev process events by turning off RC_COLDPLUG in /etc/conf.d/rc

now my boottime is only of 20s

next target: putting the modules in ram for an even faster boot  :Very Happy: 

bye

Koda

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