[Cooker] ANNOUNCE : Speedboot, phase 1, has landed on cooker

[Frederic Crozat]

Hi everybody,

just in time for beta 1 of 2009 Spring, I've finished pushing support
for phase 1 of speedboot feature.

What do speedboot :
Speedboot is trying to start first all needed actions for the graphical
system (display manager) to be able to start and then, continue all
other actions needed for a full boot, in background.

How is it implemented ?
We are reusing techniques which have been used already on some of our
OEM products, with finit, but with more standard implementation, keeping
current initscripts.

To be able to start minimal services needed for display manager to
start, we introduced S runlevel (with only 5 services : acpid, dbus,
hal, syslog and dm). Unfortunately chkconfig code only likes numeric
runlevels, so runlevel S is implemented as runlevel 7 (both represent
the same runlevel, but 7 is the one to be used in initscripts).

When booting in speedboot mode, a lot of actions which were done in
initscripts are ignored. This is why speedboot might not work on your
system. 

For phase 1 of speedboot, I disabled as much actions as possible in
rc.sysinit. Some actions just need to be delayed after display manager
is started, so I'll try to defer some of the currently disabled actions,
for phase 2 of speedboot.

In phase 2 (or 3) of speedboot, we will automatically enable speedboot
if some criteras are met and if no conflicting features are enabled on
the system, such as crypto FS, raid, network authentication. If
speedboot fails, the system will automatically fallback to standard boot
and will not retry speedboot by itself.

Currently, readahead has been completely disabled when using speedboot.
Our measures showed regressions when using either readahead or
sreadahead but they were not done on SSD drives.

How can I use speedboot ?

By default for beta 1, speedboot is DISABLED. If you want to enabled
speedboot, add speedboot keyword to your kernel commandline and reboot.

Of course, we would like to collect as much bootchart data as possible,
both when speedboot is enabled and when it is not.

If speedboot is failing on your system, we are interested too.

Enjoy

-- 
Frederic Crozat <fcrozat@mandriva.com>
Mandriva