DragonFly kernel List (threaded) for 2004-03
Re: New brainfart for threaded VFS and data passing between threads.
:Matthew Dillon wrote:
:> The recent PIPE work adapted from Alan Cox's work in FreeBSD-5 has really
:> lit a fire under my seat. It's amazing how such a simple concept can
:> change the world as we know it :-)
:Out of curiousity, have you considered some of the ideas from exokernel
Not really. As far as I can tell, all exokernel does to get its
stated performance improvement is to vertically integrate everything,
e.g. such as the web server and TCP protocol stack, into what is
essentially a single execution context.
Well, I stopped doing that the day I set aside my Amiga for a PC running
Linux, and you won't see me going back. I don't see how such a system
could ever be used in a complex production environment.... it would be
nearly impossible to track down and fix bugs.
I will be frank... I could integrate a TCP stack into a web server and
fast-path the most common connection/data/disconnect situations, but the
resulting mess would be unsupportable. It might look good in a one-off
performance benchmark but the cost of trying to maintain such a beast
over time would be horrendous. The last embedded hardware project I wrote
was based on a 10MHz 68000, and even the little UDP stack I wrote for
that was message-based and protected (via a simple protection map tacked
on to the memory subsystem) rather then vertically integrated. So,
no, exokernel does not appeal to me at all.