From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 1 Aug 2001 16:10:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 1 Aug 2001 16:10:26 -0400 Received: from quattro.sventech.com ([205.252.248.110]:16658 "HELO quattro.sventech.com") by vger.kernel.org with SMTP id ; Wed, 1 Aug 2001 16:10:12 -0400 Date: Wed, 1 Aug 2001 16:10:06 -0400 From: Johannes Erdfelt To: "Nadav Har'El" Cc: linux-kernel@vger.kernel.org, agmon@techunix.technion.ac.il Subject: Re: SMP possible with AMD CPUs? Message-ID: <20010801161005.B784@sventech.com> In-Reply-To: <20010801230441.A19396@leeor.math.technion.ac.il> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.12i In-Reply-To: <20010801230441.A19396@leeor.math.technion.ac.il>; from nyh@math.technion.ac.il on Wed, Aug 01, 2001 at 11:04:41PM +0300 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 01, 2001, Nadav Har'El wrote: > A Linux user in a local Linux club asked me whether Linux support SMP with > AMD (rather than Intel Pentium) CPUs. She said that a year ago she was told > Linux 2.2 couldn't, and that she was wondering whether the new Linux 2.4 can. > I didn't know the answer, so I started digging. > > I tried looking with various search search engines, but found nothing about > this subject. Looking through the source code, it appears that SMP with AMDs > *might* be supported, but I couldn't find any comment confirming that. The > relevant FAQs, READMEs, and so on that I found are all from the 2.2 kernel > era. > > So, does Linux support SMP on AMD CPUs? Yes. In fact, recent 2.2 kernels (2.2.20 pre patches I believe) and all 2.4 kernels support SMP AMD systems. > By the way, here's a fragment from the outdated (1999) SMP-HOWTO at > http://www.phy.duke.edu/brahma/smp-faq/smp-howto-3.html explaining why SMP > wasn't possible in kernel 2.2 and contemporary AMD processors: > > 1. Can I use my Cyrix/AMD/non-Intel CPU in SMP? > > Short answer: no. > > Long answer: Intel claims ownership to the APIC SMP scheme, and > unless a company licenses it from Intel they may not use it. There > are currently no companies that have done so. (This of course can > change in the future) FYI - Both Cyrix and AMD support the non- > proprietary OpenPIC SMP standard but currently there are no > motherboards that use it. I don't know if this was true to begin with, but I know that SMP AMD systems use the APIC SMP scheme Intel defined and uses. JE