Boot Time Optimization

[Marc Andre Tanner]

On Thu, Jan 07, 2010 at 01:48:32AM +0100, Petr Vanek wrote:
> MAT>  http://www.brain-dump.org/tmp/uImage-GTA02-bootmenu.bin 
> MAT> 
> MAT> I use a slightly modified version of Qi which I also uploaded
> MAT> although it isn't strictly necessary.
> MAT> 
> MAT>  http://www.brain-dump.org/tmp/qi-s3c2442-bootmenu.udfu
> 
> 
> wow, this is really much faster! i tried it with standard qi and also
> with yours, couldn't see a difference, but considering the hour now...

The difference is minimal yes. My Qi has lpj= preset in kernel command
line (something standard Qi probably also should add?) and it doesn't 
probe all SD partitions but directly jumpes to NAND flash if AUX is 
pressed which could have a small gain if you have lot's of partition on
your SD card. 

> i am not sure whether it has autodetection of systems, i only have NAND
> system right now and it didn't show it. i could only get the power off
> line :)

It has autodetection but I have disabled the NAND partition for now
(should probably make it configurable via a kernel command line option)
because I don't really use it and mounting the jffs2 filesystem was
just too slow for me. Don't know if this is to be expected or some error
on my side...

    root at om-gta02 / $ time mount -t jffs2 /dev/mtdblock6 /mnt/mtdblock6/
    real    0m 6.46s
    user    0m 0.00s
    sys     0m 6.32s

Ubifs should help here, I will have to read up on the recent mails
regarding the topic.

 http://wiki.openmoko.org/wiki/UBIFS 

Another idea would be to add the flash partition as a 'static' entry in
the menu and just mount it once the user presses the coresponding menu
entry. It would still take ages to mount but not for the case where you
want to boot from the sd card. However at this point we might find out
that there is no kernel stored in flash so we had an item in the list
which in fact doesn't work. Anyway because I personally use different
systems on the sd card I just disabled autodetection of NAND for now. 

> speed and need for special zimage had been blocking me from a boot menu
> system, now this is very usable (when the menu items get filled :)
> 
> keep going on, most of the work has been done already,

Yes, I will continue to play around with it if time permits.

Thanks,
Marc

-- 
 Marc Andre Tanner >< http://www.brain-dump.org/ >< GPG key: CF7D56C0