Re: [Etherboot-developers] Re: TCP and HTTP support

[<ebi...@ln...>]

ke...@et... (Ken Yap) writes:

> >> if you patch against 5.3.0 (5.1.10 is close enough) and remove all the
> >> large buffers from the stack
> >
> >I had been wondering how to do that best. I don't really need much 
> >space. The only large structures are the ones that hold the current HTTP 
> >header/state (about 100 bytes), any URL found in redirects (80 bytes), 
> >and the buffer used for assembling outgoing packets (1500 bytes). The 
> >latter is the problem. I know that none of my packets are large, so I 
> >guess I could just shrink this buffer (576 would make a lot of sense), 
> >and impose a maximum segment size for outgoing TCP packets. Would that 
> >be acceptable?
> >
> >Alternatively, I could allocate the buffer in the BSS.
> >
> >What is the prefered solution?
> 
> Put large objects in the BSS, there's no ROM space penalty for that and
> I'm less concerned about footprint now that Etherboot runs relocated.  I
> don't mind a full size packet buffer. The size should be configurable as
> I suspect somebody called Eric may want to use Etherboot across media
> with larger frame sizes someday. :-)

I just might.
 
> What I think will be interesting is learning how well it plays with
> server TCP stacks, whether breaking off a boot will leave dangling
> connections which have to timeout, and that sort of thing. And of
> course, if 50 clients all boot at once, the web server will think it's
> under attack. Anyway Jim's mob will do this testing for us. :-)

50 clients all at once...
A bitty box of a cluster :)

I have been brainstorming now that we have multicast support working
pretty well in etherboot. 

There is an alternative to multicast that in some circumstances
may be prefered.  (Say when your switch does not provide a good 
implementation of multicast).  That alternative is to build a tree
of machines where the root only transmits the image to some of them.

Does any one know a way for a machine to tell an http server it
wants to be a proxy/caching server for it?  If so I have a very
novel use of http support.  As a machine comes up it can temporarily
be an http cache for a particular boot file.

If nothing else there are some nics (like the tg3) where streaming data
works much better than a tftp ping pong because of chipset/driver
bugs.  Although tftp has always been latency limited.

Eric