Faster login

[Alex Thomsen Leth]

great job. gdm shows really fast. but of course it takes a while for
login.

lør, 13 11 2004 kl. 21:24 -0500, skrev David Zeuthen:
> Hi,
> 
> So I had a brief look at shortening startup/login time and tried
> disabling rhgb in favor of starting gdm early. It looks pretty
> promising; here are some wall-clock numbers from two runs of each
> configuration:
> 
>                        |   gdm_early  |   rhgb+gdm   |
>  ----------------------+------+-------+-------+------+
>  GRUB timeout          | 0:00 | 0:00  |  0:00 | 0:00 |
>  Starting udev         | 0:13 | 0:13  |  0:13 | 0:14 |
>  HW init done          | 0:25 | 0:25  |  0:26 | 0:26 |
>  rhgb visible          |  N/A |  N/A  |  0:36 | 0:35 |
>  gdm login visible     | 0:43 | 0:44  |  1:25 | 1:26 |
>  gdm login entered     | 0:52 | 0:52  |  1:31 | 1:32 |
>  GNOME banner visible  | 1:13 | 1:14  |  1:40 | 1:41 |
>  Nautilus Background   | 1:33 | 1:32  |  1:51 | 1:52 |
>  Panel visible         | 1:43 | 1:43  |  2:02 | 2:02 |
>  HD activity off       | 1:59 | 1:56  |  2:13 | 2:14 |
> 
> The milestones should be pretty self evident. This is on a stock FC3
> system running on a IBM T41 1.6GHz (running on AC power), 512MB RAM
> without any services manually disabled. 
> 
> In addition to starting gdm early, the modifications also start up a few
> services, D-BUS, HAL and NetworkManager, that is critical to the GNOME
> desktop.
> 
> Some random thoughts/observations:
> 
>  - We get the gdm window 40 secs faster 
> 
>  - The 12 secs from "Starting udev" to "HW init done" can be mostly
>    shaved away/run in parallel
> 
>  - Kernel bootstrap time (13 secs) can probably be much shorter
>    (that's what some kernel guys say anyway)
> 
>  - With this hack we shave twenty secs of the booting time (e.g. from
>    GRUB until you can use your PC) but booting still feels much quicker
>    because of the interaction with gdm in the middle (YMMV; e.g. placebo
>    effect etc.)
> 
>  - rhgb+gdm spawns an X server each which is sort of stupid and unsafe
>    (or so some Xorg guys tell me). This solution, per design, avoids
>    doing that
> 
>  - we don't get the kudzu screen nor the fsck screens or any other
>    console interactions. However, IMHO, such screens are not good UI
>    in the first place - we should instead have GUI replacemnts that
>    possibly notifies you when you log into the desktop session (stuff
>    like NetworkManager and HAL alleviates such problems for networking
>    and storage devices)
> 
>  - we don't get service startup notification, but, uhmm, is it really
>    useful learning that the "Console Mouse Service" or "Printing Sub-
>    system" have started? Instead, this stuff could just be put in gdm
> 
>  - it could be interesting to make /sbin/init own a D-BUS service that
>    gdm and other stuff can query and interact with. Could also be fun
>    to completely replace it with something a'la the SystemServices
>    prototype that Seth did last year; links
> 
>    http://www.osnews.com/story.php?news_id=4711
>    http://www.gnome.org/~seth/blog/2003/Sep/27
> 
>  - Could be interesting to instrument the kernel with some pagefault
>    counters etc. and attempt do more readahead on e.g. the GNOME libs
>    (both Windows XP and Mac OS X does all that; I think we do too but
>    I've been told it can be improved)
> 
> So, anyway, I think it could be interesting to discuss starting gdm
> instead of rhgb. If you want to try out my crude hack, grab the file
> here
> 
>  http://people.redhat.com/davidz/newinit.sh
> 
> put it in on your system as /newinit.sh, chmod a+x it and change this
> line /etc/inittab
> 
>  si::sysinit:/etc/rc.d/rc.sysinit
> 
> to these two lines
> 
>  #si::sysinit:/etc/rc.d/rc.sysinit
>  si::sysinit:/newinit.sh
> 
> and you should be set to go! If it breaks you get to keep both pieces;
> e.g. try this at your own risk [1].
> 
> Cheers,
> David
> 
> [1] :if it doesn't work you can boot your kernel with init=/bin/sh, do a
> 'mount -n -o remount,rw /' and edit your /etc/inittab file to point to
> the original sysinit.
> 
>