Replacing rc(8) (Was: FreeBSD Boot Times)

[Brandon Falk]

As the original poster of this thread, I can also say that Doug is 
correct. The issue is not rc, it is the actual kernel boot process. 
Maybe I could see rc becoming an issue in a massive server environment 
where there are a lot of userland processes to start, but that delay 
would most likely be in the programs themselves and not rc (I think of 
rc as more of a dispatcher).

When it comes to a desktop/laptop/simple server and all you do with rc 
is configure a static IP, start dbus/hal/sshd, and maybe launch a few 
jails... at least 90-98% of the boot process is spent doing the kernel work.

-Brandon

On 6/18/2012 6:53 PM, Doug Barton wrote:
> It's unfortunate that this thread evolved into a discussion about
> replacing rc.d, since that's almost certainly not relevant to the
> original topic of improving the overall boot time.
>
> If you analyze the boot process thoroughly you should see that out of
> the total time taken to boot, nearly 0 is spent by rc.d actually doing
> something. Almost all of the actual time is spent waiting for other
> stuff, either the kernel (primarily) or the services that the system is
> running actually starting up.
>
> The latter item is the only place where making changes to rc.d is going
> to help, and only then by parellelizing, and even then you are not
> really going to gain much since most things at boot time are serial.
>
> So while talk of how to get your favorite boot-time manager into FreeBSD
> may be entertaining, it's not likely to be productive, and almost
> certainly isn't going to help the goal of actually making the boot time
> faster.
>
> But, I'm willing to be proven wrong by someone who actually _implements_
> one of these systems and can demonstrate, in a statistically rigorous
> fashion, how much the boot time is improved.
>
> Doug
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