From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757386AbXK0ET0 (ORCPT ); Mon, 26 Nov 2007 23:19:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755221AbXK0ETT (ORCPT ); Mon, 26 Nov 2007 23:19:19 -0500 Received: from qmta07.westchester.pa.mail.comcast.net ([76.96.62.64]:46203 "EHLO QMTA07.westchester.pa.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755204AbXK0ETT (ORCPT ); Mon, 26 Nov 2007 23:19:19 -0500 X-Greylist: delayed 420 seconds by postgrey-1.27 at vger.kernel.org; Mon, 26 Nov 2007 23:19:18 EST X-Authority-Analysis: v=1.0 c=1 a=PGn15t7drhMA:10 a=GG0w21oKAAAA:8 a=pQs5aej7AAAA:8 a=Cl1uwOHQh07nyNwJ_2kA:9 a=RF9A9rAkMEI3anD7jCLicO-t0KkA:4 a=c5zHXd76wwQA:10 Message-ID: <474B9944.5050804@comcast.net> Date: Mon, 26 Nov 2007 23:12:52 -0500 From: John Richard Moser User-Agent: Thunderbird 2.0.0.6 (X11/20071022) MIME-Version: 1.0 To: Andi Kleen CC: Christoph Lameter , akpm@linux-foundation.org, travis@sgi.com, Mathieu Desnoyers , linux-kernel@vger.kernel.org Subject: Re: [rfc 08/45] cpu alloc: x86 support References: <20071120011132.143632442@sgi.com> <200711200416.32954.ak@suse.de> <200711201301.25373.ak@suse.de> In-Reply-To: <200711201301.25373.ak@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: > On Tuesday 20 November 2007 04:50, Christoph Lameter wrote: >> On Tue, 20 Nov 2007, Andi Kleen wrote: > You could in theory move the modules, but then you would need to implement > a full PIC dynamic linker for them first and also increase runtime overhead > for them because they would need to use a GOT/PLT. On x86-64? The GOT/PLT should stay in cache due to temporal locality. The x86-64 instruction set itself handles GOT-relative addressing rather well; what's a 1% loss on x86 is like 0.01% on x86-64, so I'm thinking 100 times better? I think I got this by `-fpic -pie` compiling nbyte benchmark versus fixed position, each with and without on 32-bit (which made about a 1% difference) and on 64-bit (which made a 0.01% difference). It was a long time ago. Still, yeah I know. Complexity. (You have the ability to textrel these things too, and just rewrite non-PIC, depending on how you feel about that) -- Bring back the Firefox plushy! http://digg.com/linux_unix/Is_the_Firefox_plush_gone_for_good https://bugzilla.mozilla.org/show_bug.cgi?id=322367