*BSD News Article 62859


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From: julian@mailhub.tfs.com (Julian Elischer)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Threads
Date: 5 Mar 1996 07:47:48 GMT
Organization: TRW Financial Systems, Oakland, CA
Lines: 29
Message-ID: <4hgrj4$6se@times.tfs.com>
References: <4h167r$j9j@the-fly.zip.com.au> <4he825$5rk@bone.think.com>
NNTP-Posting-Host: mailhub.tfs.com

In article <4he825$5rk@bone.think.com>,
Tony Kimball <alk@lion.think.com> wrote:
>Is there a plan for any BSD to incorporate kernel-schedulable threads
>in the forseeable future?

yes and no.
in -current there is a threads package derived from the MIT pthreads package.
it is hoped that the original MIT pthreads package will also become available
as a standard module.. (the uthreads package in -current has some
slight differences in how some situations are handled).

there are plans to use the 'rfork()' call (from plan 9) 
to implement "shadow processes" which is another way of
achieving the same thing as kernel threads except that each kernel
thread has it's own PID.. (but in reality all the address space etc. is
shared, so it looks like a thread of the same process).
abut the only way you can tell if you have standard "threads"
or shadow processes, is that you get a different response to getpid().
so "Yes" we are planning on supporting "threads" over the top
of shadow processes. 

rfork is now in -current, but does not yet support all the features
needed for this.. the uthreads package however
is worth having a look at even without it, though
the documentation hasn't arrived yet....

julian