From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751248AbWFSIyk (ORCPT ); Mon, 19 Jun 2006 04:54:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751258AbWFSIyj (ORCPT ); Mon, 19 Jun 2006 04:54:39 -0400 Received: from mx2.suse.de ([195.135.220.15]:29900 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1751248AbWFSIyi (ORCPT ); Mon, 19 Jun 2006 04:54:38 -0400 From: Andi Kleen To: Zoltan Menyhart Subject: Re: [discuss] Re: FOR REVIEW: New x86-64 vsyscall vgetcpu() Date: Mon, 19 Jun 2006 10:54:29 +0200 User-Agent: KMail/1.8 Cc: discuss@x86-64.org, Chase Venters , Brent Casavant , Jes Sorensen , Tony Luck , linux-kernel@vger.kernel.org, libc-alpha@sourceware.org, vojtech@suse.cz, linux-ia64@vger.kernel.org References: <200606140942.31150.ak@suse.de> <200606170855.49123.ak@suse.de> <44966383.1030006@bull.net> In-Reply-To: <44966383.1030006@bull.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200606191054.29543.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Probably I have not explained it correctly: > - The "information page" (that includes the current CPU no.) is not a > per CPU page If it isn't then you can't figure out the current CPU/node for a thread. Anyways I think we're talking past each other. Your approach might even work on ia64 (at least if you're willing to add a lot of cost to the context switch). You presumably could implement vgetcpu() internally with an approach like this (although with IA64's fast EPC calls it seems a bit pointless) It just won't work on x86. -Andi