Saving 10 seconds on boot

[Graeme Gregory]

On Thu, Jun 12, 2008 at 02:58:04PM +0100, Graeme Gregory wrote:
> Thanks to some hints I got on #oe I think I have a method of saving us
> 10s of boot time.
> 
> The method is quite simple, we pre-fill the /dev directory with the
> static devices built into the kernel that we know are there.
> 
> We then dont run udevtrigger/udevsettle in the init script.
> 
> The downside to this method is SD driver needs to be modular otherwise
> we lose hotplug detection of the card/partitions. This of course means
> root on SD cant be supported in this setup.
> 
To reply to my own post, you get the same time saving with populating
/dev by using the busybox applet mdev.

The only issue here is mdev by default doesnt do the renaming the
same way as udev does. But I think this should be fairly easy to fix
in mdev.conf and possibly with patches to mdev.

The only final issue I forsee here is we use a bit of udev fanciness to
create a link from touchscreen0 to the correct event device. But its
this kind of fanciness that slows udev down. So we would need to make
this link another way (without knowing in advance which eventX interface
was a touchscreen).

Graeme