From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cthulhu.engr.sgi.com (cthulhu.engr.sgi.com [192.26.80.2]) by neteng.engr.sgi.com (980427.SGI.8.8.8/970903.SGI.AUTOCF) via ESMTP id KAA35826 for ; Fri, 17 Jul 1998 10:47:34 -0700 (PDT) Return-Path: Received: (from majordomo-owner@localhost) by cthulhu.engr.sgi.com (980427.SGI.8.8.8/970903.SGI.AUTOCF) id KAA19730 for linux-list; Fri, 17 Jul 1998 10:47:11 -0700 (PDT) mail_from (owner-linux@relay.engr.sgi.com) Received: from xtp.engr.sgi.com (xtp.engr.sgi.com [150.166.75.34]) by cthulhu.engr.sgi.com (980427.SGI.8.8.8/970903.SGI.AUTOCF) via SMTP id KAA82271 for ; Fri, 17 Jul 1998 10:47:09 -0700 (PDT) mail_from (greg@xtp.engr.sgi.com) Received: by xtp.engr.sgi.com (950413.SGI.8.6.12/911001.SGI) id KAA18722; Fri, 17 Jul 1998 10:47:02 -0700 From: "Greg Chesson" Message-Id: <9807171047.ZM18720@xtp.engr.sgi.com> Date: Fri, 17 Jul 1998 10:47:02 -0700 In-Reply-To: "William J. Earl" "Re: What about..." (Jul 17, 7:11am) References: <9807162230.ZM17359@xtp.engr.sgi.com> <199807171411.HAA11412@fir.engr.sgi.com> X-Mailer: Z-Mail (3.2.3 08feb96 MediaMail) To: "William J. Earl" , Alex deVries , Igor Loncarevic , SGI Linux Subject: Re: What about... Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux@cthulhu.engr.sgi.com Precedence: bulk Bill is, of course, quite correct. In addition to the observations about the scale of the system, realize also that a ccNUMA machine has a memory system for each cpu node in the system. The physical base addresses of these blocks of memory are aligned on multi-gigabyte boundaries. The high-order bits of the address designate the cpu node, the rest address the physical memory, etc etc. What this means is that physical memory space has many "holes"... The idea of a simple buddy-system allocator as is ingrained in the Linux kernel falls apart completely in the face of this kind of architecture. I suppose you could run a copy of Linux on every node, but I consider that an excuse rather than a solution. g -- Greg Chesson