DragonFly kernel List (threaded) for 2004-04
Re: New brainfart for threaded VFS and data passing between threads.
Matthew Dillon wrote:
: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.
Have you read any papers on 'container shipping'? This sounds
alot like the stuff that a friend of mine did for his thesis.