Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757117AbZFISHW (ORCPT ); Tue, 9 Jun 2009 14:07:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751537AbZFISHL (ORCPT ); Tue, 9 Jun 2009 14:07:11 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:51426 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751158AbZFISHK (ORCPT ); Tue, 9 Jun 2009 14:07:10 -0400 Date: Tue, 9 Jun 2009 11:06:10 -0700 (PDT) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: "H. Peter Anvin" cc: Ingo Molnar , Nick Piggin , Rusty Russell , Jeremy Fitzhardinge , Thomas Gleixner , Linux Kernel Mailing List , Andrew Morton , Peter Zijlstra , Avi Kivity , Arjan van de Ven Subject: Re: [benchmark] 1% performance overhead of paravirt_ops on native kernels In-Reply-To: <4A2E7B40.4070608@zytor.com> Message-ID: References: <4A0B62F7.5030802@goop.org> <200906032208.28061.rusty@rustcorp.com.au> <200906041554.37102.rusty@rustcorp.com.au> <20090609093918.GC16940@wotan.suse.de> <20090609111719.GA4463@elte.hu> <4A2E7B40.4070608@zytor.com> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1302 Lines: 30 On Tue, 9 Jun 2009, H. Peter Anvin wrote: > > A major problem is that distros don't seem to be willing to push 64-bit > kernels for 32-bit distros. There are a number of good (and > not-so-good) reasons why users may want to run a 32-bit userspace, but > not running a 64-bit kernel on capable hardware is just problematic. Yeah, that's just stupid. A 64-bit kernel should work well with 32-bit tools, and while we've occasionally had compat issues (the intel gfx people used to claim that they needed to work with a 32-bit kernel because they cared about 32-bit tools), they aren't unfixable or even all _that_ common. And they'd be even less common if the whole "64-bit kernel even if you do a 32-bit distro" was more common. The nice thing about a 64-bit kernel is that you should be able to build one even if you don't in general have all the 64-bit libraries. So you don't need a full 64-bit development environment, you just need a compiler that can generate code for both (and that should be the default on x86 these days). Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/