Date: Sun, 05 Dec 1999 19:19:17 -0700 From: Wes Peters <wes@softweyr.com> To: Nick Hibma <hibma@skylink.it> Cc: Doug Barton <Doug@gorean.org>, freebsd-hackers@FreeBSD.ORG Subject: Re: Basic question about threads and SMP Message-ID: <384B1D25.DFAF198E@softweyr.com> References: <Pine.BSF.4.20.9912051047400.297-100000@henny.jrc.it>
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Nick Hibma wrote:
>
> Being multi-threaded has almost nothing to do with being
> multi-processor. Multi-threading means that your application has
> multiple threads of execution that are able to run simultaneously.
>
> The multi-processing capability of your box means that 2 threads of
> execution, be it a process or a thread within a process, are executed
> _literally_ at the same time, and not in simulated concurrency like it
> happens on a UP box.
Note that this happens ONLY if both threads of execution are processor
mobile. If your system supports user-space threads as part of a
process and the process can't be split across CPUs, you might as well
have a UP system. (Except everything else can run on the other
processor, so SMP is still a small win.)
This is the situation with threads and SMP in -current.
--
"Where am I, and what am I doing in this handbasket?"
Wes Peters Softweyr LLC
wes@softweyr.com http://softweyr.com/
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