From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263448AbTJBSjZ (ORCPT ); Thu, 2 Oct 2003 14:39:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263464AbTJBSjZ (ORCPT ); Thu, 2 Oct 2003 14:39:25 -0400 Received: from opersys.com ([64.40.108.71]:56077 "EHLO www.opersys.com") by vger.kernel.org with ESMTP id S263448AbTJBSjI (ORCPT ); Thu, 2 Oct 2003 14:39:08 -0400 Message-ID: <3F7C7180.2020404@opersys.com> Date: Thu, 02 Oct 2003 14:42:08 -0400 From: Karim Yaghmour Reply-To: karim@opersys.com Organization: Opersys inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 X-Accept-Language: en-us, en, fr, fr-be, fr-ca, fr-fr MIME-Version: 1.0 To: Keir Fraser CC: "Theodore Ts'o" , xen-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Jacques Gelinas Subject: Re: [Xen-devel] Re: [ANNOUNCE] Xen high-performance x86 virtualization References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Keir Fraser wrote: > Full recursion needs full virtualization. Our approach offers much > better performance in the situations where full virtualization isn't > required -- i.e., where it's feasible to distribute a ported OS. I noticed that the SOSP Xen paper briefly mentions Jacques Gelinas' work on VServers (http://www.solucorp.qc.ca/miscprj/s_context.hc). While Jacques' work hasn't attracted as much public attention as other Linux virtualization efforts, I've personally found the approach and concepts quite fascinating. Among other things, most of the code implementing the contexts is architecture-independent (save for a few syscalls added to arch/*/kernel/entry.S). So, thinking aloud here, I'm wondering in what circumstances I'd prefer using something as architecture specific as Xen over something as architecture independent as Jacques' VServers? (Granted VServers can't run Windows, but I'm asking this from the angle of people looking for resource isolation in the Linux context.) Among other things, VServers are already in use by many ISPs to provide simultaneous hosting of many "virtual machines" on the same box while maintaining strict separation between machines and still providing a secure environment. Karim P.S.: For those who aren't familiar with Jacques' stuff, have a look at this document here: http://www.solucorp.qc.ca/miscprj/s_context.hc?prjstate=1&nodoc=0 The actual concepts implemented in VServers are here: http://www.solucorp.qc.ca/miscprj/s_context.hc?s1=2&s2=0&s3=0&s4=0&full=0&prjstate=1&nodoc=0 -- Author, Speaker, Developer, Consultant Pushing Embedded and Real-Time Linux Systems Beyond the Limits http://www.opersys.com || karim@opersys.com || 514-812-4145