From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757862AbXKTDal (ORCPT ); Mon, 19 Nov 2007 22:30:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755074AbXKTDad (ORCPT ); Mon, 19 Nov 2007 22:30:33 -0500 Received: from cantor2.suse.de ([195.135.220.15]:37285 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752872AbXKTDad (ORCPT ); Mon, 19 Nov 2007 22:30:33 -0500 From: Andi Kleen To: David Miller Subject: Re: [rfc 00/45] [RFC] CPU ops and a rework of per cpu data handling on x86_64 Date: Tue, 20 Nov 2007 04:25:34 +0100 User-Agent: KMail/1.9.1 Cc: clameter@sgi.com, akpm@linux-foundation.org, travis@sgi.com, mathieu.desnoyers@polymtl.ca, linux-kernel@vger.kernel.org References: <20071120011132.143632442@sgi.com> <20071119.175116.55102316.davem@davemloft.net> In-Reply-To: <20071119.175116.55102316.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200711200425.34849.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Although we have a per-cpu area base in a fixed global register > for addressing, the above isn't beneficial on sparc64 because > the atomic is much slower than doing a: > > local_irq_disable(); > nonatomic_percpu_memory_op(); > local_irq_enable(); Again might be pointing out the obvious, but you need of course save_flags()/restore_flags(), not disable/enable(). If it was just disable/enable x86 could do it much faster too and Christoph probably would never felt the need to approach this project for his SLUB fast path. -Andi