Re: Detecting SMP

From: Tigran Aivazian (
Date: Wed Feb 21 2001 - 13:01:46 EST

On Wed, 21 Feb 2001, Jeff Garzik wrote:

> On Wed, 21 Feb 2001, Tigran Aivazian wrote:
> > yes, just run the famous mptable program. If the machine is SMP then it
> > will have a valid Intel MP 1.4 configuration tables so the program will
> > show meaningful output.
> Does that allow you to detect multiple processors... or just an SMP board?

the answer is in section 4.1 of the Intel MP 1.4 spec:

   "An MP-compliant system must implement the MP floating pointer
    structure, ..."

So, one would normally expect this to mean an SMP board rather than
multiple processors, _HOWEVER_, I can imagine a very clever MP-aware BIOS
implementation which detects that there are many processors and prepares
MP floating config table and does _not_ prepare it otherwise. So, it all
depends on the BIOS implementation.

Actually, I never tried unplugging all-1 processors from my SMP machines
and seeing what sort of MP table is left...


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This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 21:00:25 EST