From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 3B6121381F3 for ; Thu, 1 Aug 2013 21:38:35 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id E36D6E0AE0; Thu, 1 Aug 2013 21:38:28 +0000 (UTC) Received: from ironport2-out.teksavvy.com (ironport2-out.teksavvy.com [206.248.154.182]) by pigeon.gentoo.org (Postfix) with ESMTP id D56F0E09A2 for ; Thu, 1 Aug 2013 21:38:27 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av4EABK/CFG4rxNq/2dsb2JhbABEvw4Xc4IeAQEEATocKAsLIRMSDwUlN4gLBsEtjWGCSGEDjX6IDoV+iHCBXoMT X-IPAS-Result: Av4EABK/CFG4rxNq/2dsb2JhbABEvw4Xc4IeAQEEATocKAsLIRMSDwUlN4gLBsEtjWGCSGEDjX6IDoV+iHCBXoMT X-IronPort-AV: E=Sophos;i="4.84,565,1355115600"; d="scan'208";a="20379429" Received: from 184-175-19-106.dsl.teksavvy.com (HELO waltdnes.org) ([184.175.19.106]) by ironport2-out.teksavvy.com with SMTP; 01 Aug 2013 17:38:19 -0400 Received: by waltdnes.org (sSMTP sendmail emulation); Thu, 01 Aug 2013 17:38:20 -0400 From: "Walter Dnes" Date: Thu, 1 Aug 2013 17:38:20 -0400 To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Recommendation for CPU type in QEMU? Message-ID: <20130801213819.GA30464@waltdnes.org> References: <20130731101124.GB26440@waltdnes.org> <51F8EADC.1010006@fastmail.co.uk> <20130801010232.GC27364@waltdnes.org> <51FA0334.8050105@hadt.biz> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51FA0334.8050105@hadt.biz> User-Agent: Mutt/1.5.21 (2010-09-15) X-Archives-Salt: 9b14d7db-d79a-4dba-a625-5538b462f49e X-Archives-Hash: 925c9cc91980ca40b378ca6cc6fec800 On Thu, Aug 01, 2013 at 08:41:56AM +0200, Michael Hampicke wrote > You can use march=native on your gentoo hosts, that's no problem, as > long as you don't use it on your guests. That's the hole idea of VMs: > being able to move the virtual machine to another machine, that might be > completely different in terms of hardware. The goal is, to be machine > independent. I want to clarify one item, so please pardon me if it looks like I'm asking the same question over again. Assume that I launch QEMU with "-cpu core2duo" and set "-march=native" in the guest's make.conf. My understanding is that the gcc compiler on the guest will see a core2duo, not the physical i5 cpu on my desktop. We may be looking at different ways of doing the same thing. You're suggesting "-march=core2" in the guest's make.conf. I'm suggesting "-march=native" in the guest's make.conf, which would pick up the cpu type that QEMU sets (cor2duo). I'm trying to make things simpler, by only having to specify the cpu type once, on the QEMU commandline, and leaving gcc to adapt to the QEMU-specified cpu. -- Walter Dnes I don't run "desktop environments"; I run useful applications