Re: Make ipconfig.c work as a loadable module.

Bogdan Costescu [off-list ref] writes:

On Fri, 7 Mar 2003, Russell King wrote:

quoted

Which version is overly bloated?
Which version is huge?
Which version is compact?

... and the size is not important only because we want to make everything 
smaller, but because of how it's commonly used (at least in the clustering 
world from which I come):

the mainboard BIOS or NIC PROC contains PXE/DHCP client; data is 
transferred through UDP, with very poor (if any) congestion control. 

Only because the implementations suck.  See etherboot.

Congestion control means here both extreme situations: if packets don't 
arrive to the client, it might not ask again, ask only a limited number of 
times or give up after some timeout; if the server has some faster NIC to 
be able to handle more such requests, it might also send too fast for a 
single client which might drop packets. In some cases, if such situation 
occurs, the client just blocks there printing an error message on the 
console, without trying to restart the whole process and the only way to 
make it do something is to press the Reset button or plug in a keyboard... 
When you have tens or hundreds of such nodes, it's not a pleasure !

But this is all before the kernel is loaded.  Having booted a 1000 node
cluster with TFTP and DHCP.  From a single host with even being in the same
town, I think I have some room to talk.
 

Booting a bunch of such nodes would become problematic if they need 
to transfer more data (=initrd) to start the kernel and so network booting 
would become less reliable. Please note that I'm not saying "ipconfig has 
to stay" - just that any solution should not dramatically increase the 
size of data transferred before the jump to kernel code.

Right.  But I would suggest fixing your NBP (what PXE load) which must
be < 64K anyway if you have noticeable reliability problems.  Not that
I even suggest using PXE for production use anyway.  But sometimes
you are stuck with what you can do.

Eric