parallel booting init in C - even larger speedup

[Petter Reinholdtsen]

[Olivier Sessink]
> if that fits the needs the best, GPL is fine with me

Thank you.  I'll wait for a fixed version with the license info
included, and look at testing the speedup after this.

>>, but I
>> am not sure if I want to use your program or the startpar code to
>> start scripts in parallel. :)
>
> what is the 'startpar' code?

It is a script I found in SuSe, running scripts in parallel while
serializing the output.  The source is in the sysvinit debian package
source, and upstream is <URL:ftp://ftp.suse.com/pub/projects/init/>.
My initial tests with qemu ran into a problem with complete hang after
a while.  I suspect the problem is related to adjusting the hw clock.

> yes, it should for example buffer the standard output, and when a
> complete line is received, output that full line. Or perhaps even
> buffer 100% of the output..

The startpar program will buffer the output until the script ends, or
a timeout trigger, whatever happen first.  It seem to work fine when I
test it manually, but as I said above, it hangs the boot some times.

> a bigger issue might be if scripts require user input. For example
> fsck might need that. So perhaps the init.d dependencies should
> allow a "don't run in parallel" option too.

Yes, this is also an issue.  Not sure how startpar handle it.  There
is an interactive flag used by insserv and possibly also startpar, but
I have not investigated it yet.  I've focused on getting the
dependencies documented so far.