From owner-freebsd-amd64@FreeBSD.ORG Mon Apr 3 21:23:21 2006 Return-Path: X-Original-To: freebsd-amd64@freebsd.org Delivered-To: freebsd-amd64@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8371816A420 for ; Mon, 3 Apr 2006 21:23:21 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id E047043D46 for ; Mon, 3 Apr 2006 21:23:20 +0000 (GMT) (envelope-from scottl@samsco.org) Received: from [10.10.3.185] ([69.15.205.254]) (authenticated bits=0) by pooker.samsco.org (8.13.4/8.13.4) with ESMTP id k33LNHai041584; Mon, 3 Apr 2006 15:23:18 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <44319240.8070203@samsco.org> Date: Mon, 03 Apr 2006 15:23:12 -0600 From: Scott Long User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.12) Gecko/20060206 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Steve Kargl References: <44301C6D.3010206@rogers.com> <200604031442.43477.jhb@freebsd.org> <44318E3F.6080808@rogers.com> <20060403211943.GA99241@troutmask.apl.washington.edu> In-Reply-To: <20060403211943.GA99241@troutmask.apl.washington.edu> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=0.0 required=3.8 tests=none autolearn=failed version=3.1.0 X-Spam-Checker-Version: SpamAssassin 3.1.0 (2005-09-13) on pooker.samsco.org Cc: freebsd-amd64@freebsd.org Subject: Re: Status of NX bit support. X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 Apr 2006 21:23:21 -0000 Steve Kargl wrote: > On Mon, Apr 03, 2006 at 05:06:07PM -0400, Mike Jakubik wrote: > >>John Baldwin wrote: >> >>>On Sunday 02 April 2006 14:48, Mike Jakubik wrote: >>> >>> >>>>I was wondering what the status of the NX bit support is. Is the pmap.c >>>>code still broken or is support enabled and functioning by default? >>>> >>> >>>I don't think the status has changed. >>> >>> >> >>Well that sucks.. I guess then there really is no reason for someone to >>run in amd64 mode unless you need more than 4GB of ram. >> > > > You're joking, right? How many registers are available for the > i386? How many registers are available to an AMD64 cpu in > 64-bit mode? > You also get less efficient cache utilization due to the wider data types that are in use. It seems to be mostly a wash between the advantages of more registers and the cost of lower cache efficiency. amd64 is nice when you need more kernel address space and/or more process address space. Scott