From owner-freebsd-questions@FreeBSD.ORG Thu Oct 30 23:06:41 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 966311065678 for ; Thu, 30 Oct 2008 23:06:41 +0000 (UTC) (envelope-from fbsd06+3G=26745d50@mlists.homeunix.com) Received: from fallback-in1.mxes.net (fallback-out1.mxes.net [216.86.168.190]) by mx1.freebsd.org (Postfix) with ESMTP id 682448FC12 for ; Thu, 30 Oct 2008 23:06:41 +0000 (UTC) (envelope-from fbsd06+3G=26745d50@mlists.homeunix.com) Received: from mxout-08.mxes.net (mxout-08.mxes.net [216.86.168.183]) by fallback-in1.mxes.net (Postfix) with ESMTP id 49C29164717 for ; Thu, 30 Oct 2008 18:50:27 -0400 (EDT) Received: from gumby.homeunix.com (unknown [87.81.140.128]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.mxes.net (Postfix) with ESMTP id 1D67BD05A1; Thu, 30 Oct 2008 18:50:24 -0400 (EDT) Date: Thu, 30 Oct 2008 22:50:22 +0000 From: RW To: freebsd-questions@freebsd.org Message-ID: <20081030225022.3a6d5b46@gumby.homeunix.com> In-Reply-To: <539c60b90810301508q32d6d920re36177450954e902@mail.gmail.com> References: <539c60b90810301128j2493c4c1wc9519a6fef834490@mail.gmail.com> <539c60b90810301129x58a6e5des56c062ecbb262663@mail.gmail.com> <44iqr9rfz0.fsf@be-well.ilk.org> <539c60b90810301508q32d6d920re36177450954e902@mail.gmail.com> X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.11; i386-portbld-freebsd7.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: stevefranks@ieee.org Subject: Re: kqemu runs 2x faster on i386 than amd64!? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Oct 2008 23:06:41 -0000 On Thu, 30 Oct 2008 15:08:51 -0700 "Steve Franks" wrote: > > "Steve Franks" writes: > > > >> Guess I should've mentioned the target is 32-bit win2k... > > > > If the target isn't the same as the host, I think it's going to have > > to use (at least partial) emulation instead of direct execution... > > Yes, but isn't that the same for win2k regardless of wether the host > is fbsdamd64 or fbsdi386? Or are you talking 64 vs. 32 bit? As I understand it, the performance advantage of kqemu over ordinary qemu, comes from running many of the instructions in the emulation directly on the host cpu. An amd64 compatible processor can't run 32-bit code in 64-bit mode and vice-versa, so it's either doing some emulation or switching back and forth between 32/64-bit modes.