Quick LiveCD review

Matt Zimmerman mdz at ubuntu.com
Sat Jan 22 14:29:29 CST 2005

On Sun, Jan 23, 2005 at 06:50:35AM +1100, Jeff Waugh wrote:

>  * isolinux screens still display installer information

This is a debian-cd issue for Colin.

>  * kernel boots without quiet - will we switch to quiet and add usplash bits
>    to the livecd?

It depends on usplash progress.  If there is time to add a usplash-udeb, it
would be nice.

>  * waiting for fb message is a bit weird - could we kick udev to make the fb
>    devices appear earlier?

As discussed on IRC, I think a strategically placed udevstart (and possibly
delaying kernel.hotplug activation) might speed things up greatly.

>  * choose language dialogue string includes "for the installation process",
>    which is not (completely) true for either the installer or livecd - it
>    chooses the primary language for the final running systems, too. :-)

There are several templates which require similar changes.

>  * scanning cdrom stage took a long time on a couple of my machines (d-i)

It takes about three seconds on my laptop, and more than makes up for it in
the speed of unpacking udebs.

>  * network config still asks for my (dhcp-provided) hostname, but matt has
>    said that he has more love to give to the network configuration stage, so
>    this one will be fixed soon (better to document here than have everyone
>    else asking...)

The only reason this is still here is because it is a very convenient place
for me to switch consoles to make changes to casper before it starts up.  It
can be removed when I implement something else which gives me equivalent

>  * both detecting cdrom and detecting disks stage tried to load floppy.ko
>    when i don't have a floppy drive. we might not be able to detect this,
>    but can we avoid trying it twice? it takes a bit of time, at least on my
>    machines.

General d-i issue; loading floppy.ko seems to be slow on some systems and
very fast on others.

>  * preparing for live session stage was seeking quite a lot, and took a long
>    time to complete (as with the post-configuration boot process). could we
>    do some tricky file ordering when generating the image somehow? related
>    to readahead stuff thom's been doing, but a bit backwards ;)

The live image is an ext2 filesystem, so we don't have much control over
file placement.  readahead is a possibility, but this level of optimization
is likely going to be post-Hoary.

Consider (using my laptop as the test platform):

- The Warty live CD goes from power-on to full GNOME startup in 2:48

- The Hoary live CD does the same in 3:14

- The Hoary live CD is doing much more work, in terms of starting up
  services and configuring the system

- We haven't even exhausted the low-hanging fruit, in terms of performance

>  * "this system is going down NOW!!!" is not a good message to display when
>    starting the live image boot process ;-)

Cosmetic issues are at the bottom of my Hoary todo list, but they're on it.
Bear in mind that I was debugging init just yesterday, and _needed_ these

>  * will we have usplash for the live image bootup?

Again, depends on usplash progress.

>  * doing vile hdparm things with the livecd makes it significantly faster.
>    but i think we've pretty much determined that we can't do any of this by
>    default, right?

The best that we can do safely by default is to let the kernel handle it, I
think; it seems to be getting smarter about this as time goes on.

We could certainly create a "fast" mode which would try to enable more
hdparm parameters.  Given that, we could survey how many systems fail to
work properly when it is enabled, and possibly switch to "fast" as default
with a "safe" option.

> As a completely separate issue, the LiveCD tweaks update-notifier's Ubuntu
> CD detection, so it offers to do an upgrade with it. Oops. ;-)

This should be easy for mvo to fix; the Packages file on the live CD is 0

 - mdz

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