Re: TOE brain dump

Ihar 'Philips' Filipau
2003-08-04T08:54:52Z

Werner Almesberger wrote:
> Ihar 'Philips' Filipau wrote:
>
>> Modern NPUs generally do this.
>
>
> Unfortunately, they don't - they run *some* code, but that
> is rarely a Linux kernel, or a substantial part of it.
>

Embedded CPU we are using is based MIPS, and has a lot of specialized
instructions.
It makes not that much sense to run kernel (especially Linux) on CPU
which is optimized for handling of network packets. (And has actually
several co-processors to help in this task).
How much sense it makes to run general purpose OS (optimized for PCs
and servers) on devices which can make only couple of functions? (and no
MMU btw)

It is a whole idea behind this kind of CPUs - to do a few of
functions - but to do them good.

If you will start stretching CPUs like this to fit Linux kernel - it
will generally just increase price. Probably there are some markets
which can afford this.

Remeber - "Small is beatiful" (c) - and linux kernel far from it.
Our routing code which handles two GE interfaces (actually not pure
GE, but up to 2.5GB) fits into 3k. 3k of code - and that's it. not 650kb
of bzip compressed bloat. And it handles two interfaces, handles fast
data path from siblign interfaces, handles up to 1E6 routes. 3k of code.
not 650k of bzip.