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Date: Mon, 14 Jul 2003 17:50:06 -0400 (EDT)
From: John Baldwin <jhb@FreeBSD.org>
To: "Cagle, John (ISS-Houston)" <john.cagle@hp.com>
cc: freebsd-smp@freebsd.org
cc: =?iso-8859-1?Q?Patrik_Vesel=EDk?= <veselik@ssakhk.cz>
Subject: RE: maximum of CPUs
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On 14-Jul-2003 Cagle, John (ISS-Houston) wrote:
> If you enable hyperthreading on an 8-way server, you'll end up with 16 logical processors (and a
> *whole bunch* of APIC's) -- a scenario that is not comprehended by FreeBSD.  In other words,
> there needs to be some more engineering done on FreeBSD to support more than 8 processors
> (AFAICT).

Well, the problem is that the original APIC's only supported 15 physical
APIC IDs.  The (x)APIC's from Pentium4+ support 255 physical APIC IDs.
If the BIOS does the right thing as far as providing ID's for the I/O
APICs in the mptable and/or ACPI MADT, future versions of FreeBSD should
work just fine.

-- 

John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/