Date: Mon, 2 Mar 2009 08:20:03 -0800
From: Arjan van de Ven <arjan@infradead.org>
To: Andreas Robinson <andr345@gmail.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>, Rusty Russell <rusty@rustcorp.com.au>,
       sam@ravnborg.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/6] module, kbuild: Faster boot with custom kernel.
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> A monolithic kernel with parallelized initcalls is better - about 200
> ms faster than parallel insmods on my test system. However, it comes
> with a fairly large set of changes:
> 
> * First, you need a 200-line patch in init/main.c (do_initcalls() and
> friends)

why?
We already have async function calls; and those speed up my boot (when
enabled) significantly, by doing much of the kernel/driver init in
parallel.

My server box boots the whole kernel (including all drivers; I build
verything in) in 0.56 seconds, and my net books do it in around 1.0
seconds.

> 
> * Then the built-in module dependencies must be calculated properly,
> eg with a modified depmod, and added to the build process.

nope not if done right

> So, what do you think, should I keep going? IMHO, the slower userspace
> implementation is acceptable since it's so much simpler.

I would strongly suggest that you turn on the async function calls and
look at the boot graph of the resulting kernel boot... if you send
that to me I can also take a look and make suggestions....

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