Bug#477083: grub-pc: Is excruciatingly slow when compared to grub (legacy)

[Frans Pop]

Package: grub-pc
Version: 1.96+20080413-1
Severity: important

I have tried grub-pc a few times during my installation tests and
noticed that it is really significantly slower than grub "legacy".
This may or may not be very visible on real hardware, but in Virtualbox
(running on a fast, modern host system) the difference is 30 seconds.

With grub I am looking at the grub menu 4 seconds after I start the
virtual machine (which includes ~2 seconds of allowing to select a
different boot medium by the VM's "bios").
With grub-pc this is 34 (!) seconds.

You can clearly see the different stages too, even of the menu being
built up (numbers are seconds:
 0- 3: start virtual machine and BIOS stuff
 3   : "Welcome to GRUB!" is displayed
 3-28: occasional disk activity, but display remains the same
28   : "GNU GRUB  version 1.96" is displayed
30-32: slooowly the border is built up from top to bottom and the help
       text below is displayed
32-33: no visible action
33-34: menu items are shown and the blue background is filled in

Note that there's also #476479 ("takes 10 seconds to get to the menu")
which is currently assigned to grub-common. I'm willing to bet that report
is about grub-pc too, and not about grub "legacy".

Also, scrolling through the menu is quite slow and there's "flashing" of
the (previously highlighted) menu item line while scrolling. This is
different from the flashing mentioned in #437275.

With grub "legacy", the menu appears almost instantaneously and the
scrolling is fast and smooth.

>From my PoV as one of the core D-I developers this is a major usability
issue which would need to be resolved before I personally would consider
allowing grub-installer to install grub-pc by default.

This testing was done on an em64t dual core 3.2MHz host running Debian
amd64/unstable. Virtualbox VM had cleanly installed i386/lenny (which
also means that this should be trivial to reproduce ;-).

Cheers,
FJP