Date: Mon, 08 Jul 1996 13:42:12 -0700 From: erich@uruk.org To: Terry Lambert <terry@lambert.org> Cc: peter@spinner.dialix.com, freebsd-smp@freebsd.org Subject: Re: Running SMP Message-ID: <199607082042.NAA20837@uruk.org> In-Reply-To: Your message of "Fri, 05 Jul 1996 12:02:49 PDT." <199607051902.MAA15216@phaeton.artisoft.com>
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Terry Lambert <terry@lambert.org> writes:
> > Does anybody have documentation on the IO apic? I've got enough detail on
> > the local apic, but the IO apic is a real problem. We're stuck in the
> > painful "dumb" mode where all cpus get all interrupts in parallel with
> > each other until we can get some details on the IO apic. (somebody
> > pointed me to something from intel, but I can't find the reference anymore)
In the default modes ("PIC" or "virtual wire" for different architectures,
with the latter being more common as time goes on... i.e. pretty much all
new designs use "virtual wire" mode), external interrupts (those normally
routed via the 8259 PIC) are routed to the boot CPU only. Internal
interrupts (exceptions, etc) occur on the CPU causing the event.
> I thought I had pointed you to the www.intel.com page for the IO
> chip, and there's now a 1.2 MP document on their site, which goes into
> more detail on virtual wire (the mode I think we want to use to
> anonymize which procesor has to take which interrupt).
Maybe I'm confused, but the documents I'm aware of are somewhat different:
-- Intel MPS 1.4 document pointer, which should point to updates as
well: "http://www.intel.com/IAL/processr/mpovr.htm"
-- 82489DX User's Manual AP-388, order number 292116-002, now part of
the "Pentium (tm) Processors and Related Products" boot, order
number 241732-002
The first document above has diagrams describing both PIC and virtual
wire modes, and how they would be set up using the BIOS.
The second document contains both a description of how to program the
local unit and the I/O unit. For local unit programming, the list of
changes in the Pentium and Pentium Pro programmer's guides are necessary
for correct operation.
--
Erich Stefan Boleyn \_ E-mail (preferred): <erich@uruk.org>
Mad Genius wanna-be, CyberMuffin \__ (finger me for other stats)
Web: http://www.uruk.org/~erich/ Motto: "I'll live forever or die trying"
This is my home system, so I'm speaking only for myself, not for Intel.
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