Graphical boot issues: a.o. graphical boot twice slower then text boot!!!

[Owen Taylor]

[ CC'ing and setting Reply-To to fedora-devel ]

On Sun, 2003-10-05 at 07:47, Jaap A. Haitsma wrote:

> I've installed Severn including all the updates (except Mozilla because
> mozilla mail seems to freeze according to all the posts on this list
> after updating) on my laptop (A Dell Latitude C600).
> 
> First thing I noticed that booting was a lot slower (I even thought the
> init script was frozen). Then I changed the GRAPHICAL_BOOT variable in
> /etc/syconfig/init to no. Booting time reduced from 2 minutes till 1 minute.
> 
> The problem seems to be the kudzu service, which probes for new devices.
> If I disable the kudzu service a graphical boot takes also 1 minute.
> 
> Anybody experiencing the same thing?

The problem is likely that kudzu thinks your hardware has changed and
is patiently waiting on the other screen waiting you to press a key.

This will add 30 seconds to the boot time. Then by disabling kudzu
you gain another 8-10 seconds.

Jonathan and Bill are working on a fix for this; if kudzu wants to 
interact with the user, a vte terminal will appear on the graphical
boot screen.

I did some timing of booting with and without rhgb this evening and
the conclusion is that rhgb slows the entire boot 
(on a PIII-700 with a similar-era hard drive) by about 20 seconds,
from ~1:00 to ~1:20.

This slow down is virtually all in starting up rhgb ... from the
point where X takes control to the point where rhgb appears on the
screen is just about 20 seconds; likely this time is mostly spent
simply reading in libraries from disk, though there are some puzzling
factors:

 - When booting up without rhgb, starting gdm (X => appears on screen)
   takes around 10 seconds. But gdm uses all the libraries that 
   rhgb uses and more.

 - gdm is no faster to start when rhgb has started before, even though
   many of the libraries that gdm needs should already be in ram.

 - Running rhgb from runlevel 3 "hot" takes about 4 seconds from 
   X => appears on screen.

 - Running gdm from runlevel 3 "hot" takes about 5 seconds from 
   X => appears on screen. 

Possible explanations of these facts that really don't convince me:

A) Many of the libraries used by rhgb and gdm are used by various
   bits of the init process and are loaded parallelized with 
   other tasks between the point that rhgb starts and the point
   that gdm starts. (This only makes sense if most of the load time for
   rhgb was non-GUI libraries. Which I don't believe.)

B) One of the init steps that runs *after* we start rhgb speeds up
   the system by a large factor. (What? /etc/sysconfig/harddisks
   is run later but does nothing on this test system)

Next thing I want to do is to boot into runlevel 3 and see how long
rhgb takes to run cold there. 

(Both A) and B) predict that it should take around 9-10 seconds, so it
can't distinguish between them. But if it takes much longer that would
tend to disprove both of them.)

Regards,
						Owen