Testing fast parallell boot with Debian?

[Jonathan Ballet]

Le Tue, 04 Apr 2006 22:40:42 +0200,
Petter Reinholdtsen <pere at hungry.com> a _crit :

> 
> Here is a summary on what to do to test parallel booting with
> Debian/unstable.
> 
>  - Install the bootchart package to get a graph of the boot process.
>    Do a test boot passing init=/sbin/bootchartd to the kernel during
>    boot to activate it.
> 
>  - Edit /etc/default/rcS, insert CONCURRENCY=startpar to enable
>    parallel init.d script execution with serialized output.
> 
>  - Install the insserv package, run update-bootsystem-insserv to
>    reorder the boot scripts for maximum parallel execution based on
>    dependency information.  Review the order in /etc/rc*.d/ to check
>    that it look sane.  This step can be undone using
>    'update-bootsystem-insserv restore'
> 
>  - Edit /etc/default/rcS, switching DELAYLOGIN from yes to no, and
>    thus allow kdm/gdm/xdm to log in users while the machine boots in
>    the background.
> 
> There are also a few tests I have not tried myself:
> 
>  - Install the preload package to enable readahead at the end of
>    rc2.d/.  Not sure if this will speed up the boot or not.
> 
>  - Install the readahead package from Ubuntu,
>    <URL:ftp://ftp.ubuntu.com/ubuntu/pool/main/r/readahead/>.  The
>    files to load should probably be adjusted for Debian, but it might
>    speed up the boot nontheless.
> Does this work for anyone else but me?
> 
> Friendly,

Hi,

I just try your tips, to see if it changes something on my machine.
You can find the different bootcharts on
http://multani.info/debian/bootchart/

As you can see, my boot time is pretty high (:p), and using all of the
tips you provided didn't do anything (at least, it seems)

I (very) briefly explain what change between each chart in the url
given above :
 - the first one show "normal" boot, without doing any kind of
optimisation
 - in the second one, I added "quiet" to the boot command line. I use
framebuffer, and i noticed that it takes some time to display a lot of
text. In this case, I wanted to see if hiding all the text which is
displayed at boot speed up it a little bit ...
 - on the third one, I added the "startpar" option
 - on the fourth, I sue the update-bootsystem-insserv script (which
move all my link in /etc/rc5 to lower starting numbers ; they were from
10 to 99 before, now, they are from 0 to 20)
 - on the fifth, I move the preload startup link to be the first to be
run after switching to init 5.

I should add that in the first test, it seems that ntpdate script was
slower than usual (maybe 5+ sec. instead of 1+ sec.)


I think the beast here is checking and mounting filesystems. From this
point of view, reseirfs doesn't play very well (at all)
Dhcp configuration is quite slow too ... 


Voilà, I hope it could be useful ... Feel free to ask if you have
questions.

Regards,
	Jonathan