Re: [RFC PATCH 0/6] module, kbuild: Faster boot with custom kernel.

[Andreas Robinson]

On Fri, 2009-03-06 at 07:45 -0800, Arjan van de Ven wrote: 
> On Fri, 06 Mar 2009 16:15:43 +0100
> Andreas Robinson <andr345@xxxxxxxxx> wrote:
> 
> > On Thu, 2009-03-05 at 16:18 -0800, Arjan van de Ven wrote:
> > > On Wed, 04 Mar 2009 19:47:10 +0100
> > > Andreas Robinson <andr345@xxxxxxxxx> wrote:
> > > 
> > > the only thing I can say (the graphs are a bit complex to read) is
> > > that you are loading a LOT of very expensive modules that bring you
> > > no functionality.
> > 
> > Well, yes. It is the generic Ubuntu kernel booting in all its bloaty
> > glory. :) But this is what most users are stuck with. The distro
> > vendors won't change their ways because they want their stuff to run
> > on anything.
> 
> the problem is that you are also having things that just don't make
> sense; even for the generalized case...
> 
> but I guess that is for Ubuntu to resolve. I don't see the machines I
> run (with Fedora) exhibit this same issue; while there are a bunch of
> modules, none of the ones that are expensive-and-useless in your charts
> are there.

I think they will. Fast boot is one of the "essential" goals for Jaunty
and Karmic.

Anyway, attached is a bootchart for a cleaned up kernel with the
important (AFAIK) drivers built in.

>From this, I've found some tasks that I can set myself to. They would
obviously be the topic of other threads:

* Make the nforce2 ethernet driver (init_nic) initialize itself
  asynchronously, if possible.

* New config option: Separate initramfs decompression and
  file-system calls. Decompress as early as possible in a
  separate thread.

* Don't unpack initramfs twice. If CONFIG_BLK_DEV_RAM is
  set, the kernel decompresses the ramdisk just to see if
  it's a cpio archive or not, and then throws away the result.

* See what can be done about pci_init(), if anything.

If there's anything else regarding fastboot you think would make more
sense to work on first, please let me know.

Thanks,
Andreas

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