From owner-freebsd-hackers@FreeBSD.ORG Wed Mar 19 07:27:20 2008 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D37D01065671 for ; Wed, 19 Mar 2008 07:27:20 +0000 (UTC) (envelope-from tataz@tataz.chchile.org) Received: from smtp5-g19.free.fr (smtp5-g19.free.fr [212.27.42.35]) by mx1.freebsd.org (Postfix) with ESMTP id 83DB38FC19 for ; Wed, 19 Mar 2008 07:27:20 +0000 (UTC) (envelope-from tataz@tataz.chchile.org) Received: from smtp5-g19.free.fr (localhost.localdomain [127.0.0.1]) by smtp5-g19.free.fr (Postfix) with ESMTP id 0009E3F62B6; Wed, 19 Mar 2008 08:27:19 +0100 (CET) Received: from tatooine.tataz.chchile.org (tataz.chchile.org [82.233.239.98]) by smtp5-g19.free.fr (Postfix) with ESMTP id B4B353F626A; Wed, 19 Mar 2008 08:27:18 +0100 (CET) Received: from obiwan.tataz.chchile.org (unknown [192.168.1.25]) by tatooine.tataz.chchile.org (Postfix) with ESMTP id 903309BF12; Wed, 19 Mar 2008 07:26:16 +0000 (UTC) Received: by obiwan.tataz.chchile.org (Postfix, from userid 1000) id 7F118405B; Wed, 19 Mar 2008 08:26:16 +0100 (CET) Date: Wed, 19 Mar 2008 08:26:16 +0100 From: Jeremie Le Hen To: Jordan Gordeev Message-ID: <20080319072616.GB20579@obiwan.tataz.chchile.org> References: <47DBC800.8030601@dir.bg> <160451205650165@webmail50.yandex.ru> <47DCEBA1.8040503@dir.bg> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47DCEBA1.8040503@dir.bg> User-Agent: Mutt/1.5.15 (2007-04-06) Cc: freebsd-hackers@freebsd.org, "Andrey V. Elsukov" Subject: Re: vkernel & GSoC, some questions X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Mar 2008 07:27:20 -0000 On Sun, Mar 16, 2008 at 11:42:57AM +0200, Jordan Gordeev wrote: > > vkernel is similar to User Mode Linux technology. You can boot vkernel as a > > user mode process. I think it will be good to have similar in FreeBSD. > > There are several links: > > http://leaf.dragonflybsd.org/mailarchive/users/2007-01/msg00237.html > > http://www.dragonflybsd.org/docs/articles/vkernel/vkernel.shtml > > > > > The two links that Andrey posted are very good. I just want to add a short > summary: > A vkernel is a kernel running as a user process under a real kernel. The > vkernel runs in the CPU's priviledge ring 3. It services its child processes > like a normal kernel, but whenever a page table needs to be modified, > context switched, or some other privileged operation needs to be executed, > the vkernel asks the real kernel through a syscall interface. True, but ISTR that contrary to User-Mode Linux, the virtual memory operations are handled by the host kernel, which should increase speed. I have no pointer for this, I've got this information on #dragonflybsd. Regards, -- Jeremie Le Hen < jeremie at le-hen dot org >< ttz at chchile dot org >