[Sbcl-help] Re: SBCL threads

[William H. N. <wil...@ai...>]

On Wed, Apr 25, 2001 at 09:50:17PM -0400, Ben <be...@me...> wrote:
> i was wondering if SBCL supported threads (green or native) on
> x86 platforms (i think CMUCL does.)  if so, what's the
> interface?  symbolics?

(I much prefer to conduct discussions like this on an archived mailing
list, so I've sent this reply to sbcl-help as well as directly to
Ben.)

Stock SBCL doesn't support threads. Raymond Wiker reported just a few
days ago on the sbcl-devel list that it's surprisingly easy to get the
old CMU CL code working again, at least a little (enough to run the
old demos). I'm not motivated to work on them myself, but if there's
sufficient interest from other developers, support might be restored.

I'm sorry to say I don't know what the CMU CL interface is modelled
after. If it's anything reasonable, I'd expect the SBCL code will be
the same.

It looks to me as the threads not only will be non-native but also
will be non-preemptively-scheduled (i.e. "cooperative multitasking"),
either permanently or at least for quite a while. Little or no work
seems to've been done on locks around all the shared resources (symbol
tables, memoization caches, etc.) the system uses, which AFAIK is a
prerequisite for preemptive multitasking.

-- 
William Harold Newman <wil...@ai...>
software consultant
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