Re: Multithreaded /sbin.init? Is it possible?

[Tabris <tabris@tabris.net>]

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On Sunday 14 September 2003 01:40 pm, Eric wrote:
> Hello,
> 	I have an interesting theory. I have beginning programming expereice
> and would like the input of those that have more expereince than me.
> Please don't flame if this is a waste of time. Rather I would like an
> open discussion on the why's and why nots of this.
> 	Wouldn't the Linux Boot process be speeded up if the init program was
> multithreaded? I know a little about threads.. and I think there might
> be some complication of PPID assignment coming from the threads which
> would probably terminate instead of having a PPID of 1 which is init
> and will never terminate. (i think?). Should init scripts have a parent
> PID of 1? Does this even matter?
> 	If I am correct, whenever a programs parent dies, its parent becomes
> init anyways. So when the thread finishes execution of the script, then
> its parent would become init just as if it had started sequentially and
> directly from init.
> 	The script links in /etc/rc.d/x.d/ would be grouped according to their
> S and K numbers. That is, if you have 5 scripts that are S5, each would
> be given to a thread to execute and there would be 5 threads. The init
> process would wait for each thread to clean up before proceeding to the
> next group. I know this would happen in an undefined order, but if you
> want, for example, DHCPD to start after network then you would assing
> S5network and S6dhcpd. There would still be a defined order for
> differently numbered scripts, just the bootup process wouldnt have to
> wait for each script to terminate sequentially. Each group would only
> take as long and the slowest script instead of the sum of the execution
> time of the scripts. The init would start with the S1 scripts and maybe
> fork 3 times, wait for each to finish...., then fork maybe twice for
> the S2 group if there are two scripts, wait for them to
> finish...etc....
> 	Is this even possible?
> ----------------------
> Eric Bambach
> Eric (at) CISU (dot) net
> ----------------------
Fwiw, there is a project ongoing with this very concept in arklinux, and 
it HAS shown some improvements in boot speed. I don't know exactly how 
much, but the goal is to boot (get to a login screen) in under 30 seconds 
on a desktop type system.

cc:d to the current project maintainer.

- --
tabris
- -- 
Space tells matter how to move and matter tells space how to curve.
		-- Wheeler
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