Current Bootchart / breaking SD boot

Sander van Grieken sander at 3v8.net
Wed Jul 9 21:04:37 CEST 2008


On Wednesday 09 July 2008 12:58:15 Carsten Haitzler wrote:
> On Wed, 09 Jul 2008 07:54:00 +0100 Andy Green <andy at openmoko.com> babbled:
> > Did you see the last bootchart?  Is everyone focused on the 6 seconds
> > possible flab in kernel and kneecapping the device therefore because of
> > the sheer impossibility of doing anything else about the other two
> > minutes bringing userspace stuff up?
>
> yes - i did. say both of them. our kernel takes as long to just start init
> as my motorola rokr e6 (also linux using qt embedded) takes to boot all the
> way to the gui. that alone says to me "my god we have a lot of fat to cut
> in the kernel). just putting everything in a monolithic kernel is a huge
> reason for this.

If breaking boot from SD support only gains us 6 seconds I'd vote no.

> of course we will look at the rest of userspace, but that doesn't mean we
> should just ignore the kernel.

I dont know the motorola rokr but a large part of the speed increase is 
probably because a lot of the base services and the GUI are thrown into one 
large statically linked binary, a static /dev, no dbus.. (correct me if I'm 
wrong)

> > I guess I failed to check if you did it before I started doing it months
> > ago and found it was nice.  I explained a very strong reason --->
>
> i know you do it. this is one of the reasons our production systems will
> never improve - you never feel the pain of them as you always are doing
> something different. if you had to suffer from the same boot time as the
> rest of us every day... many times a day, you'd be thinking differently
> about the sdio driver built into the kernel - along with everything else.
> i'm just trying to point out that we should be optimising for the
> production use-case, not for a debug/kernel hacker mode. if we can get sdio
> up in much less time, then it's not much of a harm to still be there.

A 'normal' user will probably seldom reboot. I assume most of the time they 
will suspend/resume, So is boot time really such a big issue?

grtz,
Sander



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