Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754851AbZFGAxU (ORCPT ); Sat, 6 Jun 2009 20:53:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754073AbZFGAxL (ORCPT ); Sat, 6 Jun 2009 20:53:11 -0400 Received: from ozlabs.org ([203.10.76.45]:47733 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754038AbZFGAxL (ORCPT ); Sat, 6 Jun 2009 20:53:11 -0400 From: Rusty Russell To: Linus Torvalds Subject: Re: [benchmark] 1% performance overhead of paravirt_ops on native kernels Date: Sun, 7 Jun 2009 10:23:02 +0930 User-Agent: KMail/1.11.2 (Linux/2.6.28-11-generic; KDE/4.2.2; i686; ; ) Cc: Ingo Molnar , Nick Piggin , Jeremy Fitzhardinge , "H. Peter Anvin" , Thomas Gleixner , Linux Kernel Mailing List , Andrew Morton , Peter Zijlstra , Avi Kivity , Arjan van de Ven , Gerd Knorr References: <4A0B62F7.5030802@goop.org> <200906051416.19311.rusty@rustcorp.com.au> In-Reply-To: MIME-Version: 1.0 Content-Disposition: inline Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200906071023.04789.rusty@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1019 Lines: 25 On Sat, 6 Jun 2009 12:24:43 am Linus Torvalds wrote: > On Fri, 5 Jun 2009, Rusty Russell wrote: > > Distributions don't ship UP kernels any more; this shows what that costs > > if you're actually on a UP box. If we really don't care, perhaps we > > should make CONFIG_SMP=n an option under EMBEDDED for x86. And we can > > rip out the complex patching SMP patching stuff too. > > The complex SMP patching is what makes it _possible_ to not ship UP > kernels any more. "possible"? You mean "acceptable". Gray, not black and white. 1) Where's the line? 2) Where are we? Does patching claw back 5% of the loss? 50%? 90%? No point benchmarking on my (SMP) laptop for this one. Gerd cc'd, maybe he has benchmarks from when he did the work originally? Thanks, Rusty. -- 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/