5 sec boot

[Jeremy Katz]

On Fri, 2008-10-03 at 11:32 -0700, david at lang.hm wrote:
> On Fri, 3 Oct 2008, Mitch Bradley wrote:
> > david at lang.hm wrote:
> >> On Fri, 3 Oct 2008, Mitch Bradley wrote:
> >> if you don't need modules to boot, why do you need initrd? you should be 
> >> able to just do everything from the main partition.
> >
> > Our activation security system is in an initrd so that the firmware can check 
> > its signature before booting it.  The whole security thing adds a bunch of 
> > interesting wrinkles.
> 
> ouch. try to make the initrd do as little as possible.

The use of an initrd shouldn't have a substantial impact on boot time.
There should not be a significant fundamental difference in how long it
takes between booting into a userspace that happens to be from an
initrd, does a little bit and then switchroots vs booting into a
userspace off of a disk[1]

Jeremy

[1] With the one[2] obvious exception of "whatever is done in the initrd
takes time" -- but if those things are moved later, they still take the
same time.  And if they're not needed, don't do them.
[2] Also, there might be a tiny amount of time needed to uncompress the
initrd and un-cpio, but that really should be nominal.  If not, it means
other problems later in the boot sequence