Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756216AbYGJVgn (ORCPT ); Thu, 10 Jul 2008 17:36:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752955AbYGJVge (ORCPT ); Thu, 10 Jul 2008 17:36:34 -0400 Received: from terminus.zytor.com ([198.137.202.10]:55863 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752205AbYGJVgc (ORCPT ); Thu, 10 Jul 2008 17:36:32 -0400 Message-ID: <48767F4F.1010209@zytor.com> Date: Thu, 10 Jul 2008 17:29:51 -0400 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Christoph Lameter CC: Jeremy Fitzhardinge , "Eric W. Biederman" , Ingo Molnar , Mike Travis , Andrew Morton , Jack Steiner , linux-kernel@vger.kernel.org, Arjan van de Ven Subject: Re: [RFC 00/15] x86_64: Optimize percpu accesses References: <20080709165129.292635000@polaris-admin.engr.sgi.com> <20080709200757.GD14009@elte.hu> <48751B57.8030605@goop.org> <48751CF9.4020901@linux-foundation.org> <4875209D.8010603@goop.org> <48752CCD.30507@linux-foundation.org> <48753C99.5050408@goop.org> <487555A8.2050007@zytor.com> <487556A5.5090907@goop.org> <4876194E.4080205@linux-foundation.org> <48761C06.3020003@zytor.com> <48762A3B.5050104@linux-foundation.org> <48762DD2.5090802@zytor.com> <487637A1.4080403@linux-foundation.org> <487639ED.7000502@zytor.com> <48763CA6.9030802@linux-foundation.org> <487647EF.5010609@goop.org> <48764A01.1070402@linux-foundation.org> <48764C7C.5010309@goop.org> <48767692.4080504@linux-foundation.org> <487677F0.4000404@goop.org> <4876799B.7010204@linux-foundation.org> In-Reply-To: <4876799B.7010204@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1078 Lines: 26 Christoph Lameter wrote: > Jeremy Fitzhardinge wrote: > >> Percpu on i386 hasn't been a point of discussion. It works fine, and >> has been working fine for a long time. The same mechanism would work >> fine on x86-64. Its only "issue" is that it doesn't support the broken >> gcc abi for stack-protector. > > Well that is one thing and then the scaling issues, and the support of the new cpu allocator, new arch independent cpu operations etc. > >> The problem is all zero-based percpu on x86-64. > > The zero based stuff will enable a lot of things. Please have a look at the cpu_alloc patchsets. > No argument this work is worthwhile. The main issues on the table is the particular choice of offsets, and the handling of the virtual space -- I believe 2 MB mappings are too large, except perhaps as an option. -hpa -- 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/