Problem booting l4linux

Adam Lackorzynski adam at
Wed Feb 28 15:33:14 CET 2007


On Tue Feb 27, 2007 at 22:12:33 -0500, Eduard Benes wrote:
> I'm newbie in this area, and I would like to ask for help with some
> problems I run into (hope this is the right place).

It is.

> I've finally build l4linux following instructions in the
> "L4/Fiasco/L4Linux Kickstart". (please let me know if there is better
> document to start with)
> I had some problem finding out the right configuration of the
> l4linux-2.6.19-l4 kernel (could someone provide example of the .conf
> file).  Right now I'm trying to run it on real hw (How to make it run
> under qemu?)

Conceptually QEmu is the same as native, i.e. there's no difference in
the configuration.

> but when I try to boot DOpE using patched grub, it hangs
> when (at least I assume) trying to enter graphic mode. The screen
> shows this:
>   [VESA 2.0 info @ 0x75b5000, 0x2ff bytes] 
>  boot
> <blank>
> I've tried the L4Linux demo CD, but with the same result. Tried to
> boot into DOpE or console. I suspect that video card might not be
> supported.

Given it's a radeon based card I'd not expect that.

> But during many attempts, once the DOpE environment flashed
> for a second (before doing the restart routine accidentally) and that
> really surprise for me. The graphical user interface is not necessary,
> but I don't know yet how to run L4Linux in console. I'm able to get
> into kernel debugger, when I boot the L4Linux by remote serial console
> variant of grub menu.lst entries (based on the kickstart document
> mentioned above).

Good, serial console is good to have. If you want to do benchmarks on
L4Linux you should not use any graphical console but use plain PS2/VGA
with L4Linux.

> In the kernel debugger mode was logged one error:
>  [B.0] semaphore/lib/src/semaphore.c:500:l4semaphore_init():
>  Error: Missing 'deceit_bit_disables_switch' kernel feature!
>  Startup: semaphore lib initialization failed (-1)!  

You need to enable that feature in the Fiasco configuration.

> It is probably not related to the problem with video card, but might
> show some mistakes in my l4linux-2.6 kernel configuration. 

The above error message has nothing to do with L4Linux.

> My final goal is to compare performance of L4Linux and native Linux on
> real hw. I will appreciate any suggestions or study literature on this
> topic. 

Basically, make sure you do it right, i.e. only publish figures if
you're sure they are ok. Of course you should leave out debugging code
everywhere (Fiasco, L4Linux, etc.) and do the 'obvious' things right.
(Easy said, I know.)

> Other questions I would like to ask:
>  What is the right way to boot from serial console? 

You mean 'with' (instead of 'from')? You said that it already works for
you, so you are probably doing it quite right.

>  How can be achieved networking under L4Linux?

Several possibilites. First is using the network driver as in native
Linux, i.e. Linux drives the NIC. Then there's ORe, an L4 network server
that L4Linux may connect to. This server switches traffic for different
clients and may have or may not have network drivers on its own. ORe is
not very optimized right now.

Adam                 adam at

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