[LinuxBIOS] Boot Time

Stefan Reinauer stepan at openbios.org
Tue Apr 5 21:47:09 CEST 2005

* Jun OKAJIMA <okajima at digitalinfra.co.jp> [050405 18:31]:
> Then, how fast it is? The top page of the Wiki says 3 sec, 
> and "7/25/01: Dual Athlon update " issue says about 2 sec to
> boot a kernel. But this log shows it took 20 sec.
> http://www.carbotpc.com/linux/boottiming.log.txt
> It is too big difference between 2 sec and 20 sec, dont you?

>From the log you can see that Linux starts booting after 13.252secs.
This is the value the above 2-3 seconds have to be measured against.

Another thing that is needed to get to 2-3secs is to disable most 
With serial speed at 9600 you will spend an extra second for
each kilobyte of debugging output. Go disable serial POST.

Disabling sound support in filo might be a win, I have not checked

4 seconds are spent in the Linux kernel for IDE probing. There are
better mechanisms to probe for IDE devices than what Linux does. 
OpenBIOS and filo are two examples of how to do it a lot quicker. I
think some of this went into kernel 2.6, or at least I saw patches
floating around that pushed IDE probing below 1s.

> Especially, I would want to know the figures on VIA mini-ITX
> mothres with USB memory booting. It is very good that if I could
> get /bin/init started within 3 sec or such.
Use an initrd and remove the IDE driver completely from Linux. That will
speed things up a lot when using 2.4


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