Testing fast parallell boot with Debian?
Jonathan Ballet
jon at multani.info
Tue Apr 11 19:37:29 UTC 2006
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
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