Re: How many pentium-3 processors does SMP support?

[Christoph Hellwig <hch@ns.caldera.de>]

On Wed, Jul 11, 2001 at 02:16:39AM +1200, Chris Wedgwood wrote:
> On Tue, Jul 10, 2001 at 04:12:00PM +0200, Christoph Hellwig wrote:
> 
>     Why limit the user?  There are more than enough Linux system that
>     have more than 32 CPUs (SGI, DEC, Sun).
> 
> The limit is architecture dependant, for ia32/i386 is it 32.

The number of CPUs is currently globally limited to 32 by NR_CPUS in
include/linux/threads.h.

>     Making it a per-architecture value or even a config option make a
>     lot more sense.
> 
> It turns out I was full of it, you can buy off the shelf 32-processor
> systems.

You can.  But you cannot buy 32-processor PII (-Xeon) systems that are
supported by Linux.

> In anyone from Compaq is reading this, you should send me a 32-way
> Xeon ASAP just to prove they really work :)

It doesn't.

	Christoph

-- 
Of course it doesn't work. We've performed a software upgrade.