Re: proc fs and shared pids

Peter Eriksson (peter@ifm.liu.se)
Fri, 9 Aug 1996 09:36:10 +0200

> On Wed, 7 Aug 1996 20:45:04 -0400, "Theodore Y. Ts'o" <tytso@mit.edu>
> said:
>
> > From: peter@ifm.liu.se (Peter Eriksson)
> > I see one problem with this 16bit "thread-ID" idea - it's not
> > impossible one would need more than 65536 concurrent threads,=20
> > and what would one do then? Let's try to avoid stepping into the
> > 640KB-is-more-than-anyone-would-ever-need trap again...
[snip]
> > I can think of bad design decisions that result in needing more than 64k
> > threads; what I'd like to see is a legitimate example which doesn't
> > involve a bad design decision. :-)

I don't have such an application here right now. However, I can imagine that
in a couple of years from now there might very possible be one. (For
example, a Financial Stock Exchange system, processing buy/sell/statistics
calculations on a 64 processor UltraSPARC-2 multiprocessor server, while
talking to other institutions all over the world :-)

> Yup. There are applications where you can imagine a great many
> threads of context, but you can always multiplex application threads
> onto a smaller number of kernel threads.

Sure, that is how (for example) Solaris 2 does it.

However.. - I thought that Linus idea was that there shouldn't be
any separate application threads - Ie all threads should be kernel threads!

- Peter