Date: Mon, 11 Jun 2012 15:51:50 -0700 From: Garrett Cooper <yanegomi@gmail.com> To: Brandon Falk <bfalk_bsd@brandonfa.lk> Cc: freebsd-hackers@freebsd.org Subject: Re: FreeBSD Boot Times Message-ID: <CAGH67wSZpFFS9wYmauhDtQmrJaF2DK01vLTy927b8d68y429Uw@mail.gmail.com> In-Reply-To: <4FD66F7E.2060404@brandonfa.lk> References: <4FD66F7E.2060404@brandonfa.lk>
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On Mon, Jun 11, 2012 at 3:21 PM, Brandon Falk <bfalk_bsd@brandonfa.lk> wrote:
> Greetings,
>
> I was just wondering what it is that FreeBSD does that makes it take so long
> to boot. Booting into Ubuntu minimal or my own custom Linux distro,
> literally takes 0.5-2 seconds to boot up to shell, where FreeBSD takes about
> 10-20 seconds. I'm not sure if anything could be parallelized in the boot
> process, but Linux somehow manages to do it. The Ubuntu install I do pretty
> much consists of a shell and developers tools, but it still has a generic
> kernel. There must be some sort of polling done in the FreeBSD boot process
> that could be parallelized or eliminated.
>
> Anyone have any suggestions?
>
> Note: This isn't really an issue, moreso a curiosity.
The single process nature of rc is a big part of the problem, as
is the single AP bootup of FreeBSD right before multiuser mode. There
are a number of threads that discuss this (look for parallel rc bootup
or something like that in the current, hacker, and rc archives -- the
most recent discussion was probably 6~9 months ago).
Given past experience, a big part of getting past the parallelized
rc mess would be to make services fail/wait gracefully for all their
resources to come up before proceeding. It's not easy, but it's
possible with enough resources.
HTH,
-Garrett
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